Day 2: Workshop on Tipping Points, Cascading Impacts, and Interacting Risks in the Earth System

Alright, alright, welcome everyone, thank you for joining us for the second day of our

workshop

on

tipping

points

,

cascading

impacts

and

interacting

risks

in the Earth

system

. The first day was very rich in the information that was shared and presented. I want to thank yesterday's presenters and all the participants who shared their ideas and also asked fantastic questions. I'm going to turn it over to Patricia to share information to help us get off the ground and then she will guide us through today's agenda. thank you Kristen, so next slide, hello everyone, thank you so much for joining us this morning, afternoon or evening, wherever you are, before we begin the section sessions, I wanted to acknowledge that although we are gathered here today virtually, staff. and the building and facilities of the national academies where the staff is located today are located on the traditional land of the nakachth tank or the past and present of the anacostin and piscataway people.

We want to gratefully honor the land itself and the people who have stewarded it through the generations. we honor and respect the enduring relationship that exists between these peoples and nations and this land and we thank them for their resilience in protecting this land and we aspire to fulfill our responsibilities by their example a quick logistical note here all questions and answers and part of the discussion will be done via solido, so to access solido you can go to solido.com and enter the code 178311 or if you are on your mobile device you can scan the QR code and it will take you to the solido website . event and with that I'll hand it over to Kristen for today's agenda thanks Patricia okay so what we're going to focus on today are the regional perspectives of climate

tipping

points

and

cascading

impacts

and their interactive

risks

and we.

We're going to do this with plenary sessions for the first half of today and then opportunities for participants to provide broader input through breakout sessions and solid input, and we value all that input, so thank you for that, we'll have presentations. that highlight different geographic regions that will include, let's look at here First, the coast, then we'll think about the American West, then we'll look after the break, we'll look at the outlook on change in the Arctic and then also. change in the Great Plains, so with that I'll hand it over to Simon, who is the moderator for our first session, Kristen, thank you very much, um, good morning, good afternoon, good evening everyone, my name is Simon Dietz.

I am a Professor at the London School of Economics and it has been a pleasure for me to be part of the planning committee for this

workshop

, so it is a pleasure for me to moderate this first half of session two on Regional Perspectives on Climate Tipping Points and cascading impacts, as Kristen mentioned. We are going to cover two regions of the US in this session, firstly, the coastal US and secondly, the western United States. We have until 11:30 Eastern, so we're going to split the session roughly in half and talk about the US coast in the first half and the American West in the second half, as Patricia mentioned, we'll ask questions through the solido platform so that during the talks and afterwards they can write their questions in solido and can also vote on other people's questions. and as moderator I will answer the questions and read them to the speakers.

Well, for the first part of the session we are going to discuss the American coast and that is why I am delighted to have Kurt with me. store, let's see uh Kurt is a senior research geologist in the United States Geological Surveys Coastal and Marine Hazards and Resources Program uh Kurt welcome um uh, you've kindly offered to talk for about 15 minutes, so I'll hand it over to you now. Thank you, thank you, and let me continue with this, so today I'm going to talk about, uh, not the general coast of the US, but specifically the tropical islands, the ones where I'm primarily going to focus on the atolls. of the Pacific, this work was funded by the US Department of Defense and the US Geological Survey with several partners, as it is great science and I want to recognize those groups, including Noah Del Taurus, Delph Technical College, University of California, Santa Cruz and U. of Hawaii, so my tolls are low, usually ring shaped, built with several islands on that carbonate edge and all of these are built on coral reefs, so it's actually a biogeomorphic

system

where you have organisms that produce rocks that form these lands now in the United States in the Pacific Ocean we have a map here basically the northwest islands of Hawaii everything beyond Kauai all the outlying islands of the US Wake Johnston Canyon Reef Palmyra Jarvis Allen Baker and then um basically the Republic of the Marshall Islands and the Federal Islands in the eastern parts of the federal states and Micronesia, which, through our pact of free association with RMI and FSM, but also many other islands to the south, the Phoenix Islands, the Gilbert Islands in all of the Cuenca now those of the United States and those of free association of compactors we associate them through the office of insular affairs of the Department of the Interior and their and those small areas.

If we look at the new map in the lower right we see that the economic zones unique to Those small atoll islands are actually larger than the eastern US and the Gulf Coast combined, so when you think about the importance of this area, it is Department of the Interior lands on more than a dozen Department of Defense facilities, again there are large exclusive economic zones, so in terms of fishing, most of the canned tuna in the US comes from the South Pacific, there the minerals have become increasingly more in a study place for strategic minerals and, again, the United Nations that we have the defense pact with the Republic of the Marshall Islands of the third states of Micronesia.

The work we'll be showing today is based on research primarily here on Quasranatoll in the Marshall Islands, so one of the things about atolls is that they are unique and poorly understood environments. They have a very low topography, one to two. meters high elevations have very steep offshore bathymetry, meaning slopes greater than 45 degrees to 80 degrees, which compared to if you go to the East Coast and the US Gulf Coast, those are one in a hundred slopes, this is like one to one or two to one or three to one uh loose sediment and bedrock, so they're on a carbonate reef platform, so it's almost like a cemented base structure. with loose sediment on top again, it's being fed by living coral reefs, which grow and die, and most of the important thing about these islands is that they have a very limited freshwater lens, so if you look at a cross section, It basically rains on the island and that fresh water is denser than the seawater below the island and creates a layer of fresh water. a very limited freshwater lens that is the source of water for most of these island nations now they have a lot of things like housing and power plants and critical infrastructure airports they have a number of uh in the US a number of uh and critically threatened and endangered species such as pinnipeds, turtles, corals and birds, and although we focus on the atolls here, I just want to make it clear that many of these results can be translated to other areas of the high islands such as American Samoa , Guam, Puerto Rico, US Virgin Islands, because even on the high Islands most of the population infrastructure and critical habitats are located at extremely low elevations of one to two meters protected by coral reefs that are see here are those big light colored platforms when you see all the waves breaking more. on the high seas and protecting these large population centers and I would like to point out that these population centers are mainly inhabited by more than 85 percent by native Chamoro peoples, some more Samoans, Hawaiians and Marshallese, basically Micronesians and Polynesians and, in relation to the US overall, a much larger proportion than we would have.

Call at risk people under the age of 16 over the age of 65 low income, so the concern with this is the historically large waves during cyclones, which are hurricanes or typhoons every 20 or 30 years, would wash these atolls just as I would have done in Florida. or the Southeast with hurricanes damaging infrastructure, ruining freshwater supplies and destroying agriculture; However, what we are starting to see in the last decade are now those wave-driven OverWatch events that occur several times a decade and the reason that is happening is sea level. In the Western Pacific our rate has been increasing at two to three times the global average, resulting in more than a foot of net sea level rise since 1990.

Now, much of this is likely due to the Pacific Decadal Oscillation , but we know that overall sea levels continue to rise. will increase unless these islands average three to four feet above sea level, they will really be a bit of a canary in the coal mine and show what will happen to many of the similar Barrier Islands on the east coast and offshore of the Gulf. In the future, the big concern is that we think about sea level rise and we think, well, you know, sea level rise is rising at three or four millimeters a year and will increase to maybe seven or ten, but no.

It's just sea level rise. the interaction of that and waves, so the concern in coral reef environments is that protected rates of sea level rise through 2100 will be 2 to 10 times higher than how fast reefs can grow vertically and, therefore, the sea level will rise during the refloating that these. islands are built, we know that waves and shallow water break when their height is approximately equal to the depth of the water, the three meter wave can break will break in three meters of water depth, a one meter wave and a meter depth of water and we know that it runs up or how The amount of waves that run along the coast and cause flooding scales with the height of the waves, so to put this together in a diagram here, if we have our reef platform in gray, our island in orange on the right and in dark blue, showing our waves and our race.

So far, with the increase in wave height where sea level rises, we are going to have bigger waves with higher speed and less marine flooding and the resulting impact, so it is a non-linear interaction and, Therefore, with sea level rise, flooding is simply going to increase. are getting worse and worse, so sea level rise will exacerbate wage-generated flood dangers for freshwater supply infrastructure. Agriculture and habitats in those US and its affiliated islands. These are actually some images of the 2014 flood that actually occurred during our study. The objective of this work is to evaluate the resulting impact of sea level rise and its non-linear actions with storm wave-induced flooding on infrastructure freshwater availability under a variety of climate and sea level rise scenarios. to determine tipping points basically when those assets are no longer viable and for most of those islands, the lack of fresh water means there is no human habitation now on the large DoD bases.

Yes, they can afford to build $10 million and $20 million desalination schemes on many of the other islands. although we don't have the capacity to do that, therefore we are seeing that the tipping point is the availability of fresh water or simply when half the island is washed away annually, simply seawater does a lot of bad things to the infrastructure more critical, so what we did We took a bunch of global climate models and then we used them to drive global wave models and then coastal flood models that drive waves, so by putting water on the islands, we took global customer models that they dynamically reduced climate precipitation evapotranspiration and things like that. to then look at the availability of fresh water because basically you put salt water on top of the island, it contaminates that fresh water lens, you no longer have drinking water until enough new rain falls and it flushes it out, so in terms of the scenarios of climate change that we use, uh ipcc ar5 the representative profile of the country 4.5 and 8.5 type of our carbon emissions reduced by mid-century and carbon emissions without decrease again there is the ipcar5 in terms of sea level rise we use RCP 4.5 8.5 and a projection based on 80.5 plus ice sheet collapse and these are from the Department of Defense Coastal Assessment Regional Scenarios Working Group.

I will note that my esteemed colleagues have pointed out that some of these sea level rise projections are high. The Department of Defense did it because it has hundreds ofbillions of dollars. of critical infrastructure, so some of these values ​​will appear to be on the higher end of um uh compared to others, but I'll show you that that probably doesn't change the results much, where we did this study specifically for you. I need a place to calibrate and validate all of your models, um, so that we know that our models are within limits and our results before we take them to future mode.

We did this in Roy, no more about quasanat, they said in the Republic of the Marshall Islands, this is part of the Department of Defense's space and missile defense command is Ronald Reagan's ballistic missile defense test site and what we did was to turn this atoll island into the most equipped in the world with a lot of oceanographic sensors, hydrogeological sensors, neurological sensors, so again we want to capture field data to calibrate and validate our numerical models because without showing that the models work now again we will not we feel comfortable pushing them into the future.

One of the scientifically sad good things, personally, is that we actually had a big storm event in 2014 that caused significant surge and flooding, so again I said it happened, but it allowed us to really calibrate and validate our data models, so The first thing in terms of climate is that Kwajalein is located here like on the right side of the globe, more or less right where these clouds are to be exact and it's where most of the cyclones in that area that we call typhoons nucleate first. to appear. Typhoon alley hits Japan and the Philippines in the Marianas. and what we see is that historically they had about 1.5 typhoons a year in the Marshall Islands.

What we are showing with the dynamically downscaled cyclone models is that it is actually going to decrease in this area, so there will be fewer typhoons than the ones. However, the shape will be more intense and what that means is less rain and more waves. small in the future, so in terms of wave-driven flooding, what we did was we ran our future wave models with that and we did it across several different seas. surge scenarios and so what we did was basically analyze what is this storm, what is not the 20 year storm, but what is the one that will happen annually and what I am showing here is a model simulation of an annual winter storm . approximately 16 feet of highways in 15 seconds with a half-meter rise in sea level and what we are doing is watching waves that come impacting the northern north side of the island driving water over the island and covering it, which then we understand how that affects the freshwater lens so we can model the water on top of the island, then we need to look at the impact that is flooding the groundwater and what we have is where the image on the right is, we are looking north with the ocean on At the top, the lagoon, at the bottom, the island water, sorry, the model simulation is a little rotated, so now the ocean, um, if we're looking to the left, the oceans to the right, the lagoons to the left, and what happens?

We have floods, so you will see that the fresh water is in blue, the salt water is in red, we flood the northern third of the island and it runs there, we have this fresh water and what happens is that over time new rain falls on the island and slowly push that salt water that looks like yellow green water slowly down out of the freshwater lens and we will have a full recovery of that freshwater lens within about 15 months so remember we said that in the future we will have fewer typhoons in the future, which is a decrease in precipitation, we know.

In the future, these freshwater lenses will take more than 15 months to recover, so what we did then was basically model wave-driven flooding that is projected to occur once every 12 months on average for several different climate scenarios. so the top row is RCP 4.5 the middle rows 8.5 the bottom 8.5 plus the collapse of the ice sheet and what you are seeing is The bluer blue is the water that adapts and so on as we move and then from right to left are time slices, so 20 35 to 2085 So as you can see, as we move from right to left with higher sea level rises, we get more and more wage-driven flood water depths over the top of the islands and if we go from RCP 4.5 up to 8.5, then again we are Having these higher rates of sea level rise and greater flooding, now remember when we were trying to compare with our lo What we said is that with the groundwater models, if we have about a third of the island flooded, it takes about 15 months to fully recover.

We're simulating flooding every 12 months and what that means is we have to basically find out whether we're flooding one island every 12 months or a third of the island every 12 months and we're not going to get a full freshwater recovery. Now Dickinson looked at the height of the core of these islands throughout the Pacific, so these are all these atoll islands and what we see is that in the Marshall Islands the magnitude of the high sea level is about 2.4 meters, which is one of the highest in the Pacific and that means that the base reef on which the islands were built is much higher and makes it more resistant.

What we see is that most of those other atoll islands are much lower and that means that the results that we get We are fighting for the Marshall Islands is probably the best final estimate, most of the other islands will be susceptible to these types of processes long before, so what is the tipping point for these islands? Again, if it's RCP 4.5 where we see that. In a type of match where wave flooding will occur more frequently than aquifers recover, it is around 50 to 60 years for RCP 8.5, 20 to 30 years and with a potential collapse of the ice in the next decade or two, so let me remind you.

Compared to the mainland United States, these people cannot evacuate further inland, this is when there is water and when the coastal floods will occur, they will flood the island half a third of the islands annually and make there no fresh water, so that these projections project typhoons. or it becomes less frequent and brings less rain in smaller waves on the annual scales, some of the ones that happen will be much more intense, but again try to look at that tipping point where we lose fresh water, it's like that on the annual type, uh , annual. On various time scales, sea level rise will increase the magnitude of the frequency of floods caused by weight, so the islands are not likely to be very sustainable starting in the coming decades without significant investments because, let's be Honest engineers can build everything I want to say I have.

There's no doubt about that, but these islands don't have a very large GDP to build dikes to raise their structures and build desalination plants, so you know if that violence is not sustainable and they have to be evacuated, which can potentially result in some significant damage. geopolitical issues because we are not talking about something that is happening in someone else's life, these children now is when we talk about 20 to 50 years in their lives and one of the big questions and in fact I am working on an international project now is that if the islands disappear between the rise and the capture, it is still a nation, a nation and this is something that goes to the international quartz is what defines its exclusive economic zone, if those islands descend below sea level, does it lose that exclusive economic zone and What we're trying to do now is try to determine which of them can go first to best direct management actions or restoration scenarios or even the plan for evacuations in the future.

That's my presentation. If you have any questions, please let me. I know, thank you current, thank you very much, that was really fascinating as someone who was interested in sea level rise from an economic standpoint, so just a reminder to everyone that if you have a question for Kurt, please write it in solido um, I have a question from John, which is a broad question, so John describes it. The question is in terms of minimizing the cascading impacts from sea level rise to social problems. Mitigation or adaptation is preferable. Well, first I can play on my USGS.

That I don't do any policy I mean agency just science um I can say it personally just as a geoscientist in uh so I think to be honest we're too far down the road I think it's necessary to do both things. Again, rich, industrial first world nations have the ability to adapt, um, but we also control admissions, so, you know, I think they have to go hand in hand, but that's just my personal opinion, okay, We won't tell you. I also have a question from David Duncan. The question is: is it feasible to treat military base wastewater into drinking water for the native population until the groundwater recovers from wave-induced saltwater intrusions?

I do it right, they have a desalination. plant on the main island of Kwajalein, so yes, there is clearly the ability to do wastewater reclamation, and that is an option in many places, but again, there is a cost. Let's be honest, the US Department of Defense has much deeper pockets, so they are going to be able to adapt and design something longer, the concern is the outer islands, the smaller island nations, the Republic, the Marshall Islands, people like the one where there's not a big GDP, um, and you know, that's the biggest concern, but yes, the wastewater can be reused, they can also what they do, what they can also do is take that reclaimed wastewater, pump it to the top of the island and help increase the expulsion of that salt water, so they are looking at different management scenarios like that, but again, the concern in my mind as a member of this planet it's those people who can't, don't have the infrastructure to do those things, thank you, okay, the questions are coming in pretty quickly now, so the next question is from Matthew's state, so it's a scenario question.

The question is: should we look for tipping points in the most likely climate projections, i.e. ssp2 4.5 ssp4 6.0 or SSP 3 7.0? So I think 4.5 was the correct part of your analysis, but I guess the question generally asks you to comment on what are the appropriate scenarios to use in this type of analysis, well again, I apologize for putting on the USGS hat, but we ran the scenarios that managers ask us to run, and you know, like for the Department of Defense, where again you have hundreds of billions. of infrastructure dollars, they will likely look toward more advanced scenarios that may be less likely but with much greater impact.

And to me, what scenario to use is guessing how humans are going to interact with each other and with natural systems. I wouldn't put money on either of them or feel comfortable saying one is more likely than the other. Let me emphasize that, so if I use my moderator privilege to ask for a follow up on that, um, we talked yesterday. a bit about using story lines or plausible worst-case scenarios as a way to help understand these issues and perhaps plan for adaptation. Do you have any reflections on your experience in the studio about what you learned? or I didn't learn from the very high sea level rise scenario you used well, what do you mean by what?

Oh, you mean how people took that, um, yeah, so the thing is, I think they have a much better Pacific. The islanders understand this much better because it is not something theoretical in their minds, they see it and live it. You know, we talk a lot about traditional ecological knowledge or you know about traditional knowledge and they themselves can say that, oh my God, you know? My dad, my grandmother didn't see this happen that often, so when they see it, I think they see those high-level projections and it's given them great motivation and if you look at the last two appearances from the Marshall Islands, it have said during the Police, they know that we are on the front lines of climate change, so I think that those higher projections, because they potentially show the fate of their nations, are very shocking, but again I think that as pure scientists, we must provide the complete set of scenarios. because again, different people are going to plan on different timelines and we as scientists, I think it's best to give all of those options to managers so they can make the most informed decisions, so the next question is from Rich Blaustein, so uh me too.

This may take it a little outside his area of ​​expertise, but the question is: has he raised geopolitical issues? Are you aware of any climate litigation cases involving these atolls? I am aware that in the Sorry, I am going to use theWrong term, but somewhere in the United Nations is the appeals court there are many who are trying to develop lawsuits against some of the industrialized nations for basically causing emissions, so yeah. They're active, uh, lawsuits, okay, the next questions are coming incredibly fast, it's going to be an exhausting 13 minutes for you, Kurt, but the next one is from Gabrielle Dreyfus, the question is how does this information mean your research? is shared with the islands given their limited research and analysis capacity and resources, does the project include priority actions that the islands can take now to build resilience?

Well, there are two questions, one communication. Yeah, we've done everything from talking to say, the military on the base, we've talked to the Marshall Islands government, uh, we've talked to the Lenser Affairs office and, in fact, the results of this study actually caused the US government and the Martial Islands government to develop something called the Kwazulin Atoll Sustainability Lab. a place basically for Brill to bring together traditional native knowledge and Western science to help develop, so figure out how to do the adaptation, and it's a very important thing, you know, we, like we, as scientists, generally in areas where they would be , normally Think of these places as tourist places, there's always the worry of us, just, you know, the science of the resort, you know, we parachute in and do a project, write our newspaper article and go, and that is one of the parts of this project and the USGS in general. that we want to make sure that this science is used and that we need to be able to translate and communicate through all those different paths to international science through journal publications through briefings with local, territorial and national people, and then get it back .

In those users it is very important because otherwise our science, I am not saying it will be wasted, but it must be available to everyone because at the end of the day it is their land and they need to have the information in their hands. to make your management decisions, so I have a question from Isabel Varela. Isabelle asks what mitigation strategies are possible for these islands, i.e. adaptation strategies, assuming they had the resources for implementation to prevent flooding in the first place, barriers, etc., so yes, very. Good question and again you know that engineers can build anything pretty if they have the funds to do it, one of the big concerns is that they first think about putting walls on the side to stop flooding, the problem is that the reef is like a block of Swiss cheese, water flows in.

That's why again there is fresh water and salt water under the islands so you can build a wall and this is what they have done in Malaysia, the capital of the Maldives, which are our atolls, however the salt water will just float upwards. Sea level rises within that wall. So eventually you're going to have to do one of two things: raise all of your infrastructure, you know, put it on columns, or raise the island itself, and those are two of the main things that these lagoons tend to have shallower. a lot of sediment, all the sediment that is pushed over the edge of the atoll into the lagoon, there is a lot of potential material that you could dredge on the island, but again, you already have infrastructure there, so you need to move the infrastructure up and place it. remove the sand underneath it or remove the infrastructure, build the island vertically and build new infrastructure on top of it, or that will bring huge disruption and costs, but effectively, that's the right thing to do, so I'm just going to do that .

My little follow-up question to Isabelle's question, have you seen any analysis of the cost-benefit ratios of this type of adaptation strategy compared to something like a Managed Withdrawal, and in regards to the Managed Withdrawal, you raise these very important questions? of the fact that some of these islands are nation states, so Kurt, I'm wondering if you feel able to comment, do you know what the best adaptation strategy is probably going to be for this kind of thing, well, I don't know. I don't want to say which is the best type. I will lay out the options.

One is to just drop out to say Hey, listen, you know we can't hold on to all these little islands. We will bring people back into existence in higher, more defensible, or more places. Adaptive islands, you can try to hold the line everywhere, but again you have , in terms of what those cost-benefits are, I know some groups are starting to do that, you know, the World Bank and the Asian Development Bank are doing some of those studies in places like Majuro, which is the capital of the country . Marshall Islands, you know, is one end of the spectrum.

I would like to say that you know it can be done and if you look at what the People's Republic of China did in the sprotleys in the South China Sea, they basically took a bunch of small atoll islands and made them very large high islands, now they have a Very big GDP and there are a lot of geopolitical things in the situation, but we know it can be done, but again, at what cost?, but some places are already tuvalu in the South Pacific are already, as I understand it, they are starting to buy land in New Zealand, understanding that they might have to evacuate people or not correct sorry, short-term evacuation.

I don't remember the correct term for you know? migrating those people to new higher lands, the same goes for the US, you know, potentially buying places in Hawaii and things like that, so there's a whole range of possibilities, but it's those people's decision, so I don't want to speculate what the right decision is. or the best option to do it, it's actually a good segue into a question from Marianne. So Marianne asks how those places that are already experiencing impacts are doing, how they are adapting. You give some examples and then cut them up, but maybe you could put them in order. to put it together and characterize the different ways that these communities are already adapting well, one thing is that a lot of these places have agriculture like tarot, where you need some fresh water because they grow there. some little fresh water basins in the middle, they're starting to make basically like concrete bathtubs that are, you know, half a meter or a meter high and they're growing their tarot in that to be able to handle minor flooding, um, you know, They are starting to do it again. create at least a seawall around your airfield so that it reduces the amount of when there is a flooding event at least it's not dumping more sediment on the runway.

They are trying to increase the number of basically cisterns to collect more rain. move that rain and that water into tanks instead of storage tanks just above the ground instead of just keeping it in the freshwater lens, so there are adaptive measures again, increase a lot of coastal armoring to try to reduce the overwashing, again, tuvalu, you know? we are already designing again we are already looking to identify sand resources in the lagoon to start dredging and placing on the islands, so there are several ways to adapt the big problem is again salt water or it does not work wonders for the majority of man or It is created by man. things in critical infrastructure, so the concern is all that underground infrastructure, usually you put water pipes, sewage pipes underground, electricity, you can go up pretty easily, but the biggest concern is those and I haven't seen them very good.

Personally, I haven't seen anything on how to deal with them. a lot of that underground infrastructure and how to adapt it, so would it be fair that a lot of the examples you gave sound like, you know, people making small investments in their own properties? Would it be fair to say that most of the infrastructure is underground and how to adapt it? The adaptation that's happening right now is of that nature and not just a big public goods adaptation or it's a complete suppression that I got. I think that's false because again, bigger things like rain catchments and bigger infrastructure, I mean, they're more public again. some of the things like you know raising your beds and you know making your raised beds Terra and I guess maybe to some extent the shielding sometimes is a house you know property by property, but these again, these island nations are in the On the front lines, they are seeing it, their governments are trying to take action and, again, larger groups, the Asian Development Bank, the World Bank and others, are putting significant resources there to help them at least get started on their path. along the paths of adaptation.

I have a few minutes left, I have some questions here. I think we've covered several of them, so I'm just going to do one or two more, so I have a question from Sarah G. The question is: Do you have or plan to include elements of environmental justice in future research? Well, that's a great point and, um, I'm really sorry and this is just my own perspective. I feel like a lot of environmental justice is a problem. because often to scale, as a perfect example here, we did this study on this DoD island and not on adjacent wholly native-owned islands, so one of the things it's about is scaling this up and we're doing that and extrapolating to those other places that again are primarily native and again at-risk people, so yeah, we're trying to do that in the continental United States, we're definitely doing that, you know, it's not like we're just looking at those rich houses in Cape Cod, but When we do regional studies along the entire southeast coast of the US, the entire coast of California, right now we are finishing work on the main islands of Hawaii, American Samoa, Guam, and again there are between 80 and 90, 84 and 98 native peoples again at risk, so Yes, we are developing that sea level rise impacts the science that addresses these environmental justice issues.

One thing I would also like to point out is that one of the adaptation measures I forgot to talk about is growing those reefs. faster to provide more protection to break those waves and make the islands grow bigger. The Department of Defense has a new $120 million program called reefense to develop advanced corals to grow faster. Become more resilient to reduce coastal flooding. With that done, we've done some theoretical calculations in Florida and Puerto Rico that show that, going back to some of your cost-benefit questions, there will be benefit-cost ratios greater than one and that's really interesting because that means we could use pre-mitigation funds. disaster or post-disaster restoration funds to restore coral reefs and protect coastal communities.

The good thing is that we also get all those other benefits from fishing tourism and other things that aren't even included in those cost-benefit complications, but the other thing that comes out of those studies is that it shows that restoring coral reefs to reducing coastal hazards disproportionately but largely protects native and at-risk people, children, the elderly, and low-income people at a rate almost twice as high as the general population, so we have Some of these adaptation options will be provided to help address or could help address environmental justice issues. Thanks now. I'm going to ask. I have a couple questions about sea level rise projections and possible collapse of the majors. ice sheets in relation to that, so I'm going to group these questions together.

Kurt, make that your last question, so the first part of the question is if you can comment on the robustness of the sea level rise projections and whether they are robust enough to make investment decisions and the type of second The question is: Do you know in your projections if you are taking into account the collapse of ice sheets, for example, the melting of the Thwaits Glacier? Well, first of all, it's not my predictions that are impactful. science, uh, those projections were the ones you use, yeah, I know, I just want to make it clear, hey, but where are the skill sets?

We rely on those federal academic and research partners to develop them, so again, they were all ar5. kind of era projections plus additional ideas that the department offended the task force and took, I will say they were all developed in the mid-2010s, you know, I think every new study that seems to come out of Antarctica shows that. There's more warm water under those glaciers, um, and I think we're learning more and more that that's more likely than previously thought. Now you talk about robustness, which one will be more accurate again. I can not talk about that.

I'm just saying that I think we're understanding thatthat's a much bigger concern than we ever thought. Okay, Kurt, thank you very much. I really enjoyed your talk once again and thank you for answering all these many and varied questions like the first time we have done so. I had a session in exactly this format and what I can think of is that it's a really good time for Q a, so you've done a turn there, thank you very much, thank you for the opportunity to share. Science appreciates it, so now we will move on to the second part of the session.

It will be about the American West. I am pleased to introduce you to Gordon Grant. Gordon is a research hydrologist with the U.S. Department of Agriculture Forest Service at the Pacific Northwest Research Station in Corvallis Oregon and also a courtesy professor in the College of Atmospheric and Oceanic Earth Sciences at Washington State University. Oregon Gordon, thanks for joining us, you've got about 15 minutes and you've got your slides. so please take it, thank you very much Simon and good morning to you wherever you are and thank you to the committee, the panel and the staff for inviting me to participate in this, all of us who talk about regions and consequences.

Inevitably we are going to have to reduce our scope, quite dramatically, the regions are big places, so today what I am going to focus on with respect to the American West is the issue of water, obviously one that is prominent in this region, but more specifically I'm going to focus on the availability of water in the summer and the motivation for this is perhaps well understood as the water paradox in the west, which is that water arrives in the winter as we have been seeing in California during the last weeks, but many of the fishing demands of cities for agriculture occur in the summer, so this lag between when the precipitation arrives and when the demand is greatest led the famous American hydrologist Mark Twain a Just keep in mind that the solution to our water problems is more rain.

Only a fool would edit Mark Twain, but I've done it and the focus of what I'd like to point out is something that's a little more manageable than simply praying for more rain. But the real key water questions in the West often revolve around the question of storage, that is, how do we take the water that arrives in the winter and translate it into availability in the summer, which of course raises the question of where it is stored? stores water. the landscape and it is stored in different places, of course, it is stored, uh, first of all, it has snowed and this is a layer of snow, it is stored as dams and reservoirs that are kind of built for the purpose, it is stored as groundwater and groundwater as we will.

There are different types of Valley groundwater systems, perhaps better recognized, like what we've seen in the San Joaquin Valley of California, but there is also mountain groundwater and I'm going to talk about that towards the end of the talk because I think it plays a particularly important role in the future of water in the West, so the reason I've conjured up this whole setup is that I think there's a veritable Buffet of Tipping Points and cascading impacts that come with it. to this whole issue of storage in these different parts of the landscape, a combination of that in the past there was a sort of at least relative balance, which is or at least a recognized relationship between snow groundwater and then as humans reservoirs were developed but of course the first and perhaps the most significant impact and the turning point in the future is the fact that as the temperature increases we know that the snowpacks are decreasing and this is happening at a remarkably fast pace, so when you come up with any kind of modeling uh, that takes us only 25 30 40 years and compare the results of that modeling exercise, even in medium scenarios, the snow layers are decreasing noticeably and this has multiple consequences, as we'll talk about in a minute, the problem is quite simple, it results from a phase change as temperatures increase, which takes you from solid to liquid forms of water and basically it is a classic in a sense, a tipping point because as the temperature increases, you literally march the snow line out of the landscape, but this does not occur at the same rate or in the same way in different landscapes and a recent paper that I really recommend and encourage the committee to Take a look at the spatial distribution of how these low or no snow scenarios are likely. manifest as you shift your focus from the Pacific Northwest to California to the Great Basin to the Colorado River, and what you see in these panels is that over time, even for a medium ensemble scenario, over time and generally in the 2050s to the 2060s, literally in almost all of these cases, the persistent snow completely left the basin and this is a dramatic change, not only for the ski areas but for all of us who live in the west and The implications of this are just beginning to be seen, so I'll be all over these examples.

I'll be pointing in the direction of the research questions, since the motivation for this entire exercise is to provide some level of guidance for the National Institute. Science Foundation I'm just going to highlight what I consider to be some of the most prominent research questions that arise around these different topic areas, so in the case of snow, which I just referred to, I think it's become some attention, but it probably deserves more as we think about these spatio-temporal relationships, since temperatures change at different rates in different places, it goes against topography, which has different elevation characteristics, but this, as I say , is something that is already being done on a landscape scale, a less appreciated aspect.

The important thing about this is that snow, the pattern of snow accumulation and melting, is not just a simple function of the hum of winter precipitation coming out of the snow, but the fact that snow interacts with other atmospheric phenomena, including atmospheric rivers, so we're seeing these. Warm rivers coming out of the South Pacific, these subtropical excursions have the potential to melt snow early in the season, so actual snow cover will be a consequence of this. From this combined, we have some interesting questions about how we monitor snow at the landscape scale and historically we've done that using point measurements or snow surveys and so on, but being able to build the city's ability to generate integrated snow estimates using satellite imagery and of other types.

I think that's another key research question, but perhaps the most fundamental and most relevant thing in light of this committee's charge is what are the consequences of this change in snow cover, which are countless consequences across the entire scope of the landscape and human use of water. These include interactions between changing snow cover and changing vegetation. the snowpack and the feedbacks to the atmosphere itself the consequences obviously through the surface and subsurface water and and in the consequences require how a snowpack that melts earlier Prepares the forest for uh for further disturbance through fire or mortality um so all of these An integrated set of questions are fundamental and really lead us to the next cascading impact, which is how this change in the set of snow processes leads to changes in the way we manage our reservoir system, the second largest department of water storage and obviously as snowpack has decreased the potential to change reservoir storage and as we saw until very recently California reservoirs were always at low levels which really raised all kinds of questions about long-term water availability and supply.

I draw your attention to the graph on the bottom left, it's not a channel, it's what's called a rules curve, which is basically the rules by which individual reservoirs are managed, and in many cases certainly for federal reservoirs. operated by the Corps of Engineers or the Bureau of Land Management. They are congressionally mandated herds that came with the authorization of the dam in the first place and any changes to the rules curve similarly have to be congressionally mandated, which encodes a certain inflexibility in how we respond to the reservoir management and, of course, how we look to the future and see climate change and the changing availability of war.

We are starting to look again at the spatio-temporal dimensions of this problem and so a recent paper pointed out the chain of what are likely to be differences in inflows both in the peak Inflows shown in the left panel and Low flow inflows to these reservoirs are shown again on the right for a set of mid-range, mid-century climate change scenarios, and what you're seeing is that at least at the national level. scale there are likely to be significant changes in the availability of flowing water much of this in the west is around the low flow there will be a significant decrease in flows under four reservoirs operating with four different objectives, as shown throughout the bottom panel, so this raises a key question: will we need to change the rules by which these reservoirs are paired?

In other words, how do we introduce this non-stationarity in the climate signal into our reservoir management strategies? The strategies that are already being employed that you would think would have already been developed, but in fact, at a fairly early stage, is this idea of ​​using forecasts to inform reservoir operations and I'll show you an example shortly. Wait, but this is certainly a management strategy that deserves attention. What it leads to is thinking that if we have problems with winter flooding and summer, the need for summer storage, how do we trade these things off against each other and that is the challenge that dam operators face and of course, that plays out against a very large and complex legal and institutional environment, water rights, water supply and the whole question of environmental flows for fish, temperature and light.

This is just an example of what I was referring to. earlier of these forecast-informed reservoir operations that are being experimented with, so to speak, and it's an example of how in a flood that occurred in February of '96 on the west coast, how if some advance forecast had been used to drive releases from in this case, Lake Mendocino which at the end of the storm is shown in blue and red on the right, more water would be retained as storage that would then be available during the summer, so I think this type of thinking is hardly I'm just starting to get into the realm, but as I say, it's going to face some legal and even political challenges, I want to focus my attention on something that I think is going to be of increasing importance as we think about Western water and we're certainly coming to tipping points, they are likely to arise, that is the whole issue of groundwater and as I said before, groundwater comes in these different flavors, it comes as groundwater from the Valley and as groundwater from the Mountain, uh, from the Mountain.

I'm going to talk to the valley's groundwater first. I think it is not a surprise to most of us that the intensive utilization of the valley's aquifers primarily for agriculture has resulted in dramatic depletion that is particularly significant during droughts, which is why Jfama Yeti and his colleagues work using the grace . Satellite imagery has been able to document this depletion of what is often a rather cryptic and hidden resource, which is groundwater which we can now measure from satellites using gravitational potential, the differences over time and the dramatic change in the availability. of groundwater, particularly as I say during droughts, one can combine this not only with these volumetric measurements of the available groundwater, but we are also looking at the subsidence of the landscape accordingly, so the point here is that we have these new methods to detect this problem, but that doesn't tell us what to do about it.

It just reports the fact that the rates and the time trajectories of it, so the kinds of questions that this raises, of course, are your problems. How do we think about extraction in its spatial and temporal dimensions? How much water is available? What are the consequences for the substance and what are in some sense the long-term water availabilities that we continue to use? for various purposes, a question that has arisen a little more recently is the question of whether we can do something about it. Can we, in some sense, try to reconcile the problem that Mark Twain pointed out about this out-of-date balance by some kind of recharge of groundwater systems during the winter, when precipitation is abundant, making water available in summer and there are a variety of schemes that people have talked about, including the artificial recharged injection ofgroundwater back into the system and includes more passive, but attractive schemes. like Levy setbacks that would allow rivers to reoccupy their floodplains and, in principle, recharge groundwater during times like we're seeing now in California.

However, the effectiveness of this is not known and I think it is a key area for uh for research um, I haven't talked about it, but at the bottom of all of this are problems related to water quality, the salinization problems that have occurred, contamination from agricultural products and so on, and how do we think about this in the consequence of the depletion of the groundwater system and, of course, this branches out into a much broader social question about how we think about our agriculture in general , if we should grow almonds, for example, in water-challenged landscapes, and what does that mean and what are the adaptation strategies that we should employ in this, okay, so that's the valley system.

I want to draw attention to what I consider an underestimated component of the water situation in the West and which is a rather unusual presence of large volumes of water stored within the bedrock. Then the volcanic landscapes themselves, I think, have enormous consequences for how we look to the future and imagine water utilization and availability in the West. Here's the thing, while it's about those waterfalls which, in light of the title of this workshop, seem quite appropriate, the northwestern United States is a volcanic park that lies in the path of the prevailing westerly winds that They are loaded with humidity, the consequence of this is that we receive very high rainfall in a landscape that has very young volcanic rocks.

Layers that in some cases can be kilometers deep. This is a region that extends ignoring the border fault that between the United States and Canada stretches from Canada to northern California and the consequence of this in a certain volcanic sense. sponge, so to speak, is that there are very large quantities of water and we are talking here about cubic kilometers of water that are stored at altitude in the mountain range of that, as I say, particularly from northern California to Oregon and mainly then towards the South. Washington and this is the water that feeds the rivers of at least this region and drains the Cascades, which includes some of the major rivers in the system, so if you look at the pre-dam unregulated flow into the Port of Portland .

Let's say in Oregon about 95 percent of the August flow comes from this deep volcanic system that is primarily late in the season the result of very large cold water springs, as you saw on the previous slide, so what you're seeing Here is the proportion of the flow into Poland Harbor that comes from these different tributaries and that, in a sense, the greater Willamette River system is almost entirely a spring-fed river at this time of year, giving it a sense of the importance of this volcanic aquifer, but it's not just the Willamette, if you go down to the Sacramento River, the same story applies to a lesser extent, but almost 60 percent of the unregulated flow into the Sacramento Delta comes from a few rivers.

Pit River, Fall River, uh, which have their origin in this deep volcanic elevation, so there is a huge relationship between the presence of this volcanic aquifer and the availability of summer water and this is where Safi Khan in Merced has given us , and so on, if you look down the road where the snow has melted where the reservoirs are unreliable in their ability to supply water. I maintain that this is the future of at least some of the water in the West, we will see a shift and in a feeling almost like some kind of social tipping point where the northwest of the US is likely to be seen as the tower of water from the West because of this gift of volcanic system and you can see this comparison between the Southern California system and Northern California. the depth of water in the aquifer is pronounced and this has huge implications for where people are, for industries, for where the salmon are, and I think it's an underrated aspect of the future, which is that as other storage sources of water decrease this The geological water supply is going to be assumed with increasing importance, but it raises the whole set of questions that we are just beginning to answer, how much water is there and where it is stored, this is a cryptic resource, we cannot see it , we can only measure it where it appears as a screen flow, what are the The consequences of these other dynamics have referred to the change in snow cover.

The effects of vegetation on this deep groundwater resource. How many years even though we think there are years of stored water? What are the consequences of drought in such a deep groundwater system? The spring dynamics are likely to be, as these play an external role in supplying the rivers and one of the things I would point out in the same way that we are using remote imaging as a way to capture groundwater dynamics, the emergence of near-surface geophysics. As a tool, I think it's an extremely important and potentially revolutionary aspect of our ability to say and do science and answer some of these fundamental questions, and the ultimate question is the whole question of how these large groundwater systems interact. with vegetation, with fires, with other disturbances in the landscape, so what I want to leave you with is this notion that water in the West is not a simple problem, no one, no, I think even Twain would agree with that, but It is fundamentally a critical zone problem.

It involves interactions between different parts of the landscape between the atmosphere the water stored on the surface the water stored in the subsoil interaction between these storage reservoirs and the stress flows of evapotranspiration and that to understand the system we are in I am going to have to address it in its integrated and cascading sense and, if I do that, I will end with a request, which is that I think there is an opportunity here and I think that the work of the committee can help with this to promote the notion of regional centers where these types of issues, these integrated problems that include both the geophysical and biological dimensions, but also very clearly the social dimensions, can be brought together, studied, examined and engaged with uh for this critical resource that really affects us all thank you very much Gordon, thank you very much now I'm going to remind you participants that if you have a question for Gordon, write it in solido where you can also upvote other questions, so I have a few questions on the way to Gordon, the first is from David Duncan Doe.

Is there a role for restorative forestry in trapping more scarce water from snowmelt in the tree root fungal soil ecosystem, eh, the very interesting thing? a question I didn't address directly, but I hope Craig Allen maybe points it out because Greg, Naomi and I wrote an article more or less along these lines, which is true, we didn't answer it, but it raised the question of whether They could manage forest systems so that they don't produce chain flows, which is the way people exist, there is some kind of meme or catechism out there that you know that forests produce water, that's not true, forests consume large amounts of water, there is the largest. consumptive use, but what we don't know is whether there are strategies that could be employed to change the way water is stored in the landscape;

For example, could we cut down forests not for the purpose of producing more water downstream but specifically for the purposes of capturing snow which could therefore melt later and change the durability and sustainability of the forest during those long, slow summers? hot weather and changing the way we manage our road systems so that they intercept groundwater and convert it to surface water. We, by changing the availability, the place where the roads are located, can change the dynamics of the subsoil. The answer is that we don't know, we have never addressed this systematically. There has been some work in the early '70s in the Rocky Mountains that was actually an attempt to literally create more water by thinning and logging various types of forests, but I don't think we've ever addressed it specifically from the standpoint of and we manage the forest specifically to keep water in the forest landscape throughout it, that's a question, thank you, the next question is from John and John asks: have you seen changes in the probable maximum precipitation in the west and How does that affect water storage?

Could PMP changes be a game changer? I don't claim to know the whole story about changes in precipitation. I know where I live, the jury is out a lot on whether we're going to see anything, certainly, on the annual scale, it looks like there's more precipitation, you can, you can, you can put it, go either way depending. about how what model do you run um I don't think we're going to be I don't think Twain is going to be uh help us out here I don't think we're going to rain our way out of this problem um The southwest will almost certainly see more, sorry, see less rain. and the problem is not only the total precipitation, but when it arrives and the way in which it arrives.

I think those are the much more relevant parameters for thinking about the future okay, I have a question from Dipanjana Malik and Deepanjana asks if it is possible to have a faster and more extensive water recharge in areas of depleted aquifers to send the water back to the storage through better coupled modeling and geosensor based monitoring systems hmm, not sure I fully understand this. Capture the full dimensions of that. I'm imagining the question is if we were more intentional about monitoring and measuring water seepage over large areas we could affect recharge. I'm not sure. I'm understanding the question pretty well.

I think what we can say is that our understanding of how to recharge groundwater is in its infancy. I mean, we thought about artificial injection of groundwater, but we have all kinds of problems related to that. Stays? Is available? I mean, you know, and we put it in the ground and then we have to pump it. It is an energy-intensive operation. Do we have pollution problems? migrate who owns the water, I mean, these are all issues related to this recharge. There is a lot of interest, as I said before, in the art in a more passive loading through the Levy setbacks of allowing rivers to occupy floodplains that they once occupied but again did not really know and we would need a detection system to know if This is effective in producing water that is actually not available at the times we need it and one of the key points is that the water in the groundwater cleans the Valley.

The systems move quite slowly, so you can't just put a current into the ground and then take a current out again. Well, I have a couple of questions that I think are related to this. This is the idea of ​​recharging groundwater, so you've probably already covered this, but Matthew asks if it would be possible to replenish depleted deep aquifers using winter precipitation and Julie Brigham Grit asks: Does injecting water back into the ground increase the likelihood of

earth

quakes? , oh, let me take the first one first because it's easier to talk to, in principle, you can use reservoirs, you know, rock reservoirs as a storage compartment, the problems that one encounters and this.

I want to start all this off, but I think this is not my particular area of ​​knowledge, but just what I've read from others, you know, if you have sinking, if you actually buy the pump, the act of pumping water you create substance, which It means that now you have collapsed part of that. The reservoir is not the same but the volumes do not work in the same direction. The other problem you have and again this is a critical zone problem is that you pump water into the rock and the water has no particular allegiance to whom.

Put it there, I mean, it goes on and on faults and fractures and things like that, and we're learning a lot about nature, the importance of rock fracture as a control of where water goes, so you can put it in the ground, but you can't. That doesn't necessarily mean that it will be left for you later, which Julie asks, that's a very important question and of course you know we're seeing this issue being raised around the whole issue of fracking, and there certainly seems to be which, again, I'm not aware of this literature, but there's certainly a lot of evidence that in places where you didn't have

earth

quakes before, you're suddenly seeing a lot of earthquakes because of injections, relatively small scale things. a large-scale groundwater injection program could work in a tectonically active area.

I think it's a good question. We can't turn our backs on it, but I don't have a clear answer. It's good, awesome. thanks Gordon, I'm currently learning the consequences of selecting questions out of order in solido, so I'm trying to figure out which questions I've already answered and which I haven't, soI have a but but I think I have it under control, so I have a question from Rich Blythestein Blowstein, uh, what is for the future with mountain volcanic aquifers, what lessons could be learned from Ogallala and other situations that we perceive as not sustainable. are elements of sustainable management for the future of mountain aquifers, that's a great question, and even for someone who has thought a lot about this whole topic of volcanic aquifers and their future role, no, I don't really pretend to know.

I mean, I know what here are some things that I do know, we know that unlike the Ogallala aquifer, which was basically a Pleistocene water reservoir, it's mostly old water that doesn't recharge at any point. measurable rate, you know, relative to pumping the mountain systems that we've worked on in Oregon, we have water that on average is Decatur water, it's seven, ten to fifteen, twenty years old, what that means, that It is the water that is actively at play. we can measure isotopically as part of the cycle that ends up sending water to the streams, which tells you the time scales involved that we have to think about, that doesn't mean that you know if you turn off the water tomorrow that you have 10 years in the bank because, as we all know, water is driven by pressure and what drives the water coming out today is the pressure of the water entering the aquifer, uh, even if it's not the water itself, um, what does long-term sustainability look like? term here, I think it starts with trying to get an idea of ​​what the dimensions of the water are and, as I say, we're talking about cubic kilometers, we're talking about there being, you know, in order. 10 to 20 cubic kilometers, which puts it on the same scale as reservoirs like Lake Mead or large continental lakes like Salt Lake, so we are talking about a lot of water that, but is not stored as a lake, is stored as fractures and how that size volume of water is going to respond to, say, a five-year drought or a 10-year drought.

These are the kinds of questions we should address now. This is where I think being able to monitor this using remote control using geophysics using other techniques becomes very important and I know that NSF is thinking a lot about investing in near-surface geophysics. This kind of area, this regional focus would be a beautiful target for some kind of effort along those lines, so I won't answer the question. directly, but it gives us an idea of ​​what are the dimensions and the time scales that are attributed to it, yes, yes, no very interesting big comments on that, thank you, so the next question from Suzanne Smith, a short question, Do these mountain aquifers exist? other mountain ranges in the west, well, you know, certainly, in the limestone, in the automobiles, in the imprisoned terrain, there are some similarities, but I have searched long and hard to find analogues for the Pacific Northwest in other regions and I have to admit it.

I'm an understatement, the only place I feel pretty confident in seeing a comparable juxtaposition of high humidity, young volcanoes, you know, snow and so on, is Iceland and you see very similar spring systems in Iceland to those seen. You see in Oregon, but it's a very unusual combination of features and so there's groundwater, there's rock water that's stored even in places like the Sierras, but because the Sierras are granitic, they have a lot less fractures, the rock is much tighter, it's less porous because of everything. that there are real differences in the way mountains are stored, thank you, so obviously there has been a lot of interest in these mountain aquifers, but the next questions will change the emphasis a little, so Marianne asks how do these water systems Will they impact and interact with coastal water supplies and storage?

It's a good question and I don't think it has a good answer. I mean, I think the question points to the plea that I entered into the discussion in the In the end, you know that water is fundamentally an integrated problem and water finds its way from the mountains to the valleys to the ocean and the only way to Understanding how water will be available for any of a variety of purposes in the future is to conceive and build a scientific infrastructure that encompasses that scale and scope of water transit, so I don't have a simple answer, but I know and it will probably be in different places, I mean California, during For example, the problem of where the water comes out of these volcanic aquifers is why people are talking about putting water, taking water and moving it around the Delta and putting it into the San Joaquin system of the southern California.

I mean, there's some kind of redistribution of water, so instead of letting it out to the sea, putting it out into the building, there are plans afoot in the transbay delta that would literally take advantage of this volcanic aquifer, although I don't know if people recognize it as such and translates it to Southern California, where water is much scarcer, so the point is that it's a big question that needs to be incorporated into any effort to make sense of water. Regional okay, so I have a question about Bill Copeland Reservoir, so Bill asks how many western surface reservoirs can be considered expendable. and the rivers and Bill's question just jumped excuse me while I finish it how many how many reservoirs can be considered expendable and the opposite of the ones they affect can be candidates for restoration yeah that's a very interesting question uh what do we do with the infrastructure of our prey? and of course there is a wide range of thoughts, on the one hand it is clear that dams play a huge role in affecting the ecology of river systems, often affecting the geomorphology of urban systems, and if you really want to do back the systems a direction in which they might be more suitable for anatomical fishes, but probably for other resources as well.

Dam removal, which I think is what you're referring to, is becoming a strategy and is certainly being employed at an increasing rate in my opinion. it has to be balanced with some other thought. You know, I've come to this view later, which is that right now, you know, hydropower is a pretty low-carbon resource, even as we argue about the role that reservoirs play in methane production and you You know it raises the question for me whether we should be talking about taking hydroelectric capacity offline at a time when we're really trying to transition very quickly to a clean energy economy and electricity similarly if we're faced with a warming climate. and rivers that are warming dams represent the only opportunity you have to significantly affect temperature regimes on the scale of I mean, shading works to a certain extent, but with a big river you can't do that, so I think we need to rethink it. how the reservoirs are and not enter that discussion with predetermined agendas, but really look closely at what the future poses for us and where the reservoirs fit into that problem.

Okay, Gordon, thanks, that seems like a good kind of fundamental analysis. note on which to conclude this session because we are almost out of time. I know we have a few questions left on the slide, but I think it's time to wrap up the session, so first of all, I want to say thank you once again. Kurt and Gordon, thank you very much for your talks and for your answers to the many questions you've been asked and I just want to give you an overview of what's coming up, so I think we'll take 30 minutes now. break until noon Eastern time, if I did well, someone should shout if I didn't, but if I did well, then we will start again at 12 o'clock with the second part of the session at Regional. perspectives on climate tipping points and cascading impacts and that will be moderated by Dorothy Merits so join us again in 30 minutes thank you very much foreigner foreigner foreigner foreigner foreigner foreigner foreigner foreigner thank you foreigner foreigner thank you foreigner foreigner foreign foreign foreign foreign foreign foreign foreign foreign foreign foreign foreign foreign foreign foreign foreign foreign foreign foreign foreign foreign foreign foreign foreign foreign foreign foreign foreign foreign foreign foreign foreign foreign foreign foreign foreign foreign foreign foreign foreign foreign foreign foreign foreign foreign foreign foreign foreign foreign foreign foreign foreign foreign foreign foreign foreign foreign foreign foreign foreign foreign foreign foreign foreign foreign foreign foreign foreign foreign foreign foreign foreign foreign foreign foreign foreign foreign foreign foreign foreign foreign foreign foreign foreign foreign foreign foreign foreign foreign foreign foreign foreign foreign foreign foreign foreign foreign foreign foreign foreign foreign foreign foreign foreign thank you foreign foreign foreign foreign foreign thank you for joining us for the second part of the day two of our tipping points and cascading impacts Workshop um, today we're going to focus on the outlook Regional, this morning we heard about the US coast, the American West, this afternoon we will talk about the Arctic region and the Great Plains.

We have two speakers in the Arctic region for these regional climate perspectives. turning points and cascading impacts are Dr. Terry Chapin, professor emeritus at the University of Alaska and Fairbanks, will speak first for 15 minutes and then Dr. Michelle Mack, professor at Northern Arizona University for another 15, then we will take time for questions again using solido and after 20 minutes we will address Dr. Craig Allen, professor at the University of Nebraska-Lincoln in the Great Plains and then again a question and answer session at the end until 1 20. So we are, we are here. until 1:20 and then we will go to the break rooms where people can choose to go to the break room in the region of their interest so that they can select the break room they want, as a member of the work group. group committee that has organized this workshop.

I'm very pleased to hand it over to our first speaker, Dr. Terry Chapin, thank you Terry, thank you, let's see, can I have the first slide? As Dorothy mentioned, there are two of us talking about the Arctic today, so I would like to focus primarily on the social dimensions of the Arctic tipping point and Michelle will address more of the biophysical dimensions and I would also like to take this opportunity to think quite broad on turning points. What struck me in yesterday's session is that many of the tipping points we discussed appear to be unintended consequences that lead to bad outcomes for nature and society and what I would like to focus on are the ways in which where we could trigger positive tipping points that could allow society to transform towards more sustainable outcomes, so I'll talk about this in fairly general terms and then Michelle will apply some of these ideas to her talk on the biophysical dimensions, so the next slide Well, here we go, so the main drivers of recent changes and concern about tipping points are human drivers of global population changes in our use of resources and this has impacts on the global environment , for example, through changes in temperature and the conversion of ecosystems from relatively natural ecosystems to more managed systems and these, in turn, together have consequences for ecosystems, including things such as species extinction and exexploitation and overexploitation of fishing, now together changes in the environment and changes in ecosystems have changes in benefits to society, so if we think about about two dozen different benefits that society obtains from nature, most of them are declining in terms of their delivery to society, the only ones that are increasing are the ones that are actively managed, like agriculture and aquaculture, so for me the question in terms of tipping points is what? what society is going to do about it, because it is society's interventions that will probably change the nature of these feedbacks now in Alaska, for example. 90 percent of the state's revenue comes from oil, so there's enormous political pressure to keep drilling and extracting oil, but on the other hand Alaska is also on the front lines of climate change and seeing uh, rising impacts on the environment in ways that affect both nature and people, so the question for me is what are some of the ways we could change from a tipping point that contributes to the human drivers of environmental change towards a turning point.

Point out that it could lead to a more sustainable trajectory on the next slide please, so one framework to think about this is stewardship and by this I mean actively shaping Social Ecological Change Pathways to improve ecosystem health and human well-being, now the main The key features of this are, firstly, active intervention to shape change rather than passively responding to changes imposed on us, so it involves intentional transformation rather than transformations unintentional, as we have talked about for much of this workshop. It is also important to realize. that people are part of this system, an integral part of the system and therefore they are part of nature and another feature that I would like to emphasize is that there are two equally important goals: one is the health of the ecosystem for all reasons why I have spoken in this workshop about human well-being andThis is often framed as a choice between people and nature, but in my opinion it is really one and the same people will not benefit in the long term without interventions that support nature. next slide please, the two questions I would like to discuss today are: can we deliberately trigger tipping points that could lead to desirable changes in nature and society and, if so, what are some of those desirable characteristics that we could I would like to see the leakage and if so, what are the opportunities and risks of trying to deliberate to activate tipping points towards sustainability because there will be winners, losers, winners and losers in any type of transformation, so we must think carefully about the risks and opportunities of trying to trigger transformation, but as I think we'll see as we go forward, we know a lot about how to trigger transformation and how to shape it and that's what I'd like to talk about next. next slide please for Olson uh developed a good way of thinking about transformation strategies.

He divided the process into three different phases: a preparation phase, a change navigation phase, and then a new system resilience building phase, so in terms of preparation, the obvious first step is to ask how to transform what type of correct trajectory, so it is important to define the objectives and the strategic steps, and a lot is known, but through scenario analysis on how to look at the law, the possible consequence of different uh. scenarios, so this is a technology that is well developed in science, it is also important to identify the barriers that can trigger change and allies who might be interested in navigating the change, so all of this can be done as preparation, but it often takes a little time. particular set of circumstances to actually implement them and begin to navigate towards change, for example, recently, the war in Ukraine, which has had many bad outcomes, has also created an opportunity to create incentives to promote the development of renewable energy as a way to minimize the dependence of Europe and the rest of the world on Russian oil, so here we have the opportunity to do something that may not have been foreseen and, in navigating change, one of the important things about this is that it can occur in many different directions. directions, so it is important to be flexible in terms of strategy and it is also important to be transparent so that you can involve a large proportion of society in trying to do this and be positive and think about the opportunities that can be developed and the broader perspectives.

The more you engage in these efforts to move toward sustainability, the more likely you are to be successful, and since the new system will inevitably be built primarily with pieces of the old system plus some new elements, it is important to build the resilience of the new system. so that it does not return to a previous system and this involves promoting values ​​and creating incentives that support the development of a more sustainable trajectory and then also starting the mobilization of new social networks that can support this. For example, in Alaska there are concerns about, well, no, I'll say it on the next slide, please.

Donella Meadows had a good way of thinking about transformation in terms of potential levers that could allow transformation to occur and she identified a dozen or so different levers that could trigger transformation and one of the things she pointed out is that some of These levers can cause profound changes, but are often very difficult to implement, and other level levers are much more feasible to initiate, but are less likely to do so. They cause pronouns to change and we could consider them in three groups, one that has to do with visions, objectives and values ​​that are essential for a deep systemic change transformation towards sustainability and others could be policies and behaviors that could be easier to implement , especially and/or could be implemented at more local scales and then there are various system feedback systems that are also important, so all of these levers interact with each other and the next slide please, but one of the things that this suggests is that there are potentially multiple strategies to initiate social-political turning points. uh, some of these could be difficult levers, like broadening the vision of society, others could have to do with system design feedback and others to identify policies and agents that trigger change now because the context is going to differ from a place to place, there is no rest.

A simple recipe on how to start the transformation towards sustainability and each of these could be the most effective mechanism in a particular situation. Next, let me begin by thinking about how to broaden the view of society in the 19th and 20th centuries. It has focused predominantly on profit, wealth and material comfort, and in the framework of management, the objective could be to expand it from material wealth to a goal such as human well-being, which is not synonymous with material wealth, as well one might imagine, and this does not mean that material issues need to be eliminated, but simply that complementary dimensions of human well-being need to be developed more fully.

These include natural capital, the benefits we get from natural human capital through formal and informal education and social capital, which is the ability of groups to work together through collective action and another issue is that from there there will be winners. and losers caused by any change in the system, we must pay special attention to equitable distribution among all of society, so that if there are changes that are the ones we seek to initiate, these, at least, do no harm. to those people who are more vulnerable and preferably result in more equitable outcomes, then please, one of the things I think about a lot is is this plausible, are we close to a social tipping point and are surveys telling us? do you have an idea?

In addition to this, extensive surveys in developed countries show that there is substantial concern about the future of the planet. Most people believe that human actions are driving a global tipping point and what was perhaps most surprising to me is that most people are in favor of changing the social goal of benefiting the well-being of people in nature rather than prioritizing short-term jobs over nature protection, so there is a substantial area of ​​values ​​that are compatible with a more sustainable set of actions in social ecological systems and the problem appears to be deficiency. to be how to actually implement this so that people's values ​​are translated into actions next, please let's start here by thinking about how to shape the dynamics of the system.

There are two potential approaches to this: changing norms and behavior and this can often happen through changes and values, which I talked about before, but another approach is to add that one of the most important things that would have to happen here is reduce human consumption of resources. Another general approach is to incentivize sustainable production and consumption so this is both the demand side and the supply side of market economies so either can push or pull the other so you can start anywhere or in a particular scenario, but eventually both must change next please, so let's think of various ways to change social norms. one of them is to shape values ​​through formal and informal education and one of the things that has become really clear through educational studies is that core values ​​are often developed at a very young age, so when We think about education we must think about this.

In very general terms, we must think about the role of families, friends and social networks in the educational process and we must think about the communication process. I know that when I was a child my parents didn't talk much about deep values ​​and things that were important to them, but there is no reason why that has to be the case and in terms of more formal education it is important to think about education , particularly at early ages in primary schools and not just in the university system and So, a body of social science theory, the theory of value, is about what people should do and this depends largely on the values ​​they have.

Now another approach is to think about people's identity, why they choose to do things that people often choose to have. an identity with particular groups and some of these groups have a strong identity, they have an identity that is closely shaped by values ​​and I would like to give two examples in Alaska, something like 80 percent of the territory of Alaska has a predominantly indigenous population a even though he is indigenous. people represent only 20 percent of the total population, the rest of the people in the cities also have one and one of the things about indigenous people is that the values ​​of protecting nature and being closely linked to the land and the sea is a really important part of part of their identity and they are very concerned about their livelihood opportunities in the way that environmental change is affecting that in cities religious groups are often closely linked to values ​​and religious groups They often span a broad political spectrum that is now one of the most religious groups in the United States have national organizations that have strong climate action statements that support climate action, so here is another group that cares deeply about caring creation, caring for vulnerable people, this is another way of describing values.

What we talk about in terms of sustainability, it seems to me that there is another potential audience here that could be a strong ally in the movement towards sustainability. We also need to show good practice, so one way to do this is to make visible practices, like writing, writing, work. cycling or recycling, people are often likely to be aware of them and, if these practices are associated with the groups they identify with, they are likely to move in that direction, so it is often valuable to show the good practices and avoid bad ones. and even for people who don't know the people who are involved in this, uh, people are more likely to move towards those types of practices next, please and Terry, excuse me, we're a little bit out of time, is it close to the end?

Ok, I'm sorry. Yes, I will accelerate it to incentivize changes that can be made through taxes and subsidies, punishing those who break the rules, for example vested interest issues and improving the rules. I would like to skip the next slide and continue. to the next and here from one path to another is to think about empowering society for change. This can be done by engaging an influx of influential actors who are sometimes not the ones we usually think of, so in addition to social movements and NGOs, think about corporate citizenship. and ways in which this could be encouraged and then also think about new democratic institutions, for example, citizenship for nature instead of corporate citizen assemblies instead of party conferences to negotiate internationally, next slide please, and there are many places where these kinds of approaches can start and I think it often makes sense to start where we have the most traction with our own behavior in talking to neighbors and sharing the values ​​we care about about the world our children will live in, for example in our community, on the climate action planning committee that I am involved in.

I often emphasize the co-benefits, such as saving money by reducing energy use and improving safety in terms of reducing the risks of natural disasters, and since the US has a history of laws with large negative impacts on the climate I think a workshop on tipping points held here by the National Academy suggests that the United States would be a great place to start and push energy reduction to emphasize public concerns about energy costs and security and encourage us. a transition to sustainability thank you, thank you, it was a very timely presentation, we appreciate it and now we are back with Dr.

Michelle Mack, professor at Northern Arizona University, for her second presentation on the Arctic region, okay, can you see this first slide? Yeah, cool, okay. Well thank you very much. I'm going to talk about Arctic tipping elements on both a local and global scale and I just wanted to start with this recent figure as a touchstone for thinking about climate tipping elements. We know that these elements in the Arctic system. They are amplifying human-driven climate change and this rate of warming is actually driving these elementstowards tipping points where positive feedbacks are self-perpetuating both within the Arctic system and then cascading through the Earth system where they're going to drive fundamental changes in the Earth system, you're familiar with the collapse of sea ice that changes reflectivity.

Global heat transfer through the atmosphere and ocean or the melting of the Greenland land ice sheet that will affect sea level rise, but today I want to focus on terrestrial elements since I am a terrestrial ecologist and there are impacts on the climate through the carbon cycle, so we have permafrost soil thinking about boreal and arctic permafrost, so technically they are soils and sediments that have been frozen for more than two years, but in many cases these have been frozen for millennia and also the cold northern forests of the boreal biome now both elements of the Arctic system contain globally important organic carbon pools, so 10 to 15 grams of energy from these pools are shown here in carbon pedograms.

Carbon fixed by photosynthesis and the Pleistocene and stored in frozen permafrost soils could be released today through respiration as these cold soils warm due to photosynthesis and respiration, but as a formative characteristic of these cold ecosystems, Exchange flows have a huge time span. Because of the large size of these carbon pools, particularly their size relative to the atmospheric carbon pool, we know that small changes in the exchange rate can have globally important impacts on atmospheric carbon. These reservoirs are now sensitive to climate warming and governed by threshold behaviors. in the case of permafrost soil it is frozen versus thawed it is also ice much of this soil has a large volume of ice versus collapse of that ice melting of ice and collapse of materials in space as the ice melts now in the forests is a little different Old versus new forests, the disturbance score initiates succession processes, these forests are always dynamically in chains, although in slow changes, and their biome expands or contracts.

The forest expands or contracts. The thought of permafrost itself is really. I consider him to be the mastodon in the room as he has been identified. an element in the tipping framework that can vary from regional to global in its impact on greenhouse gas concentrations, um, and then the border forest, I think it's more of a regional tipping element, the threshold dynamics have the potential to have both forcing Regional forcing on climate, but They also have cascading interactions with permafrost because of these really unique system-level behaviors that I want to talk about today, so I'm going to talk about threshold dynamics in the cycle of Boyle Forest carbon and its cascading effects on permafrost.

Northern latitudes, it's part of the historical disturbance regime, it's climate-driven, it's increasing as the climate warms, and it's a climate-sensitive disturbance, so what we're seeing now with warming is that the footprint of the fire is growing, there is an increase in intensity, so the amount of energy released increases in severity, so the proportional change in ecosystems caused by fire and there has been a very dramatic increase in the area burned annually . Now, in the case of a warming-driven disruption, like a wildfire, we have the potential to increase. feedbacks between the biosphere and the atmosphere, so increasing temperature, warming and drying, increased lightning activity, which triggers more fires on the landscape, which then transfers carbon from ecosystems to the atmosphere, creating this immediate positive feedback to warming through carbon emissions, but we know that fire also alters these long-term controls on the Earth's carbon cycle, so it affects carbon inputs and outputs, and these factors control the carbon balance of the ecosystem during the fire cycle, between fires that in many areas of the boreal region are on the order of a hundred to perhaps a thousand years is fine, so in addition the fire can have other interesting effects that could reinforce or even balance that positive feedback from the initial combustion and is through the feedback of temperatures to atmospheric warming through albedo or evapotranspiration and through um effects on the fire activity itself through interactions between vegetation and fire that they could even accelerate in the landscape through more flammable vegetation or they could slow fire they could suppress fire in the landscape so this combination of positive and negative interactions really sets up a complex system of outcomes for the carbon cycle um well, So historic we currently think of these coniferous forests and the boreal biome as if they had been a carbon sink on a millennial scale and this is mainly due to the organic layer of the soil, this thick layer of peat now, in each fire cycle, part of this material has escaped the burn and moved into something we call legacy carbon, so it is a legacy of the pre-disturbance ecosystem, but we know that more severe fires have caused deeper burns and you can see the burn here burning deeper in this legacy pond and in this Imagine this artistic interpretation, we have human hands that are opening the vaults of this legacy carbon in the soil and releasing it into the atmosphere, so the combustion of this legacy carbon actually indicates that a unprecedented disruption to the ecosystem, so there is no Do you know that we have gotten rid of something that has been around in many cases for hundreds of years or maybe a millennium?

So this changes the forest in a fire cycle from a relatively atmospheric carbon sink to a carbon source, so there is a first threshold behavior and that is at the ecosystem scale, but this also has two really important impacts on the long-term recovery of the carbon cycle and the first is that this unlocks self-replacement patterns between forest tree species and the succession processes of historically dominant conifers that have self-replacement. -replaced for hundreds of years, well, they are replaced by alternative succession trajectories, so new species of forest trees, but also this unlocking can expose permafrost to contemporary air temperatures and can accelerate thawing.

What we see in Alaska is that the historically dominant coniferous forest has been changing to deciduous trees like Aspen and Birch, so there is a self-reinforcing plant-soil interaction that occurs after the change in successional trajectory toward deciduous tree species that actually increases carbon storage in surface pools, but may also decrease fire activity and emissions. because of the functional traits of these broadly deciduous species and these new forests tend to be highly resilient because of the life history traits of those plants, um if we look across the continental scale of the Royal Forest in the United States. and this is a synthesis of forest regeneration after the fire.

In some cases we see relatively similar patterns in about 50 percent of the sites where we have evidence of post-fire dynamics. We saw a return to black spruce, this historically dominant species and All of these are sites that burned lightly where there wasn't much burning of that organic soil later, but when the burning was severe, when these sites burned deeply and in In some cases, inherited carbon was lost. We see Transitions and in western Canada and Alaska these Transitions are deciduous species, but further east we see transitions to what we consider a recruitment failure or poor establishment, so on the one hand we have transitions to a forest less flammable and with greater carbon storage, but on the other hand we also have possible transitions to vegetation. that could be more flammable and could store substantially less carbon, so there will be more opportunity for complexity to arise in these systems, so here I want to step back thinking about permafrost in many permafrost soil regions.

Frozen ground and ice, well, it's a legacy of the past. The climate is not in balance with the current climate due to the thick organic insulating layer of soil we just talked about burning. We know there is gradual top-down melting associated with warming, but it is equally likely that abrupt melting will occur in these ecosystems as this large volume of land ice melts. Surfaces sink and that sinking drives the cascade of rapid events. The temperature moves or the heat moves and the flowing water emerges concavity and the water gets trapped as well as the snow, which leads to warming.

A positive warm-up feedback that perpetuates even if you know if it was the trigger for the initial warm-up. The atmosphere would be removed and on hill slopes this can lead to thermal erosion. Massive waste of deep soil and sediment exposure, further accelerating. It was thought to be okay, so this is probably familiar positive feedback to you. He thought that the decomposition of old permafrost carbon releases material or traces. gases into the atmosphere in terms of carbon dioxide and in some cases methane and once the snowmelt eruption is triggered, we have cascading effects that drive ecosystem change and further accelerate decomposition and we know that wildfires are likely to be a positive trigger for all this, there could be some cases. where changes in vegetation might dampen some of these positive triggers in this cycle, but for the most part, at least in the near future, in the next 100 years, we think it will be largely a positive feedback, so here there is a photo of Royal Forest. that burns and then goes through this post-fire subsidence associated with the loss of that thick insulating organic layer.

You can see severe burns, abrupt thaws, dead trees falling into standing water where the soils have calmed down. Substantial changes in controls over the carbon cycle. Apple's short-term and long-term timescales. Alright, from here I just want to move on to talk a little bit about the contribution of permafrost, that is, carbon emissions to the global climate, so here's a landscape or a plane to think about and when we think about the impact climate of carbon emissions from permafrost, We know that it is a combination of carbon dioxide and methane that is forcing the climate and we know that the response of permafrost will depend on our warming trajectories set by humans and here I am using concentration pathways representative and these human pathways actually relate to the additional amount of carbon that will be released from the Arctic in these increasing warming scenarios.

Well, here I show you in this little bubble this is the relative distribution of the forcing associated with carbon dioxide and methane and then that red number. Are those two numbers relative to carbon so that we can think of it as the amount of forced CO2 equivalent associated with the emissions of these two gases? Okay, so what you can see here are nine possible future emissions scenarios and these are assembled from the current Permafrost Carbon Network literature and from Ted sure um in a recent post this gives us nine possibilities for future emissions and, well, in a very well-behaved world, we might expect a linear increase in these increasing climate forcing scenarios, predictable, but I know that there are these threshold changes, these feedback possibilities in the system that lead to complexities, so I think The most interesting thing here to think about is what would drive future scenarios in different directions as we encounter carbon. axis of carbon dioxide emissions we can think about the impact of both human-caused warming and these nonlinearities in climate potentially on the drying of Arctic ecosystems and the changes in ecosystems that could occur with drier soils and less water reservoirs and then, on the other hand. the methane axis going through subsidence scenarios like I described above, but also these scenarios where thinning permafrost leads to geological methane sinks and methane crater bombs that you've probably heard about in the news.

Well, I just want to borrow briefly from Terry is here to conclude this and I've been thinking a lot about what I can do as an environmentalist to address the path forward. And I think I like this framework of thinking about broadening society's vision and then I've been thinking. a lot about modifying system design and feedback and I'll tell you a little moreabout this, well, certainly to broaden the vision of society, you know, the real and most important thing is to reduce emissions and decide on the trajectory of climate change that humans follow. they're actually pushing because that's going to determine the potential scenarios that we're going to encounter, particularly with the release of carbon from permafrost.

I think in the last decade, scientists and people who are involved in, for example, the Permafrost Carbon Network have really broadened society's view of permafrost carbon um it's become commonplace in newspaper headlines it came to the ar-6 of the ipcc um so it's great, it's moving forward people are understanding that this relatively remote arctic process can affect the rest of the world. I think Wildfire 2 is having more of a peak Siberian forest fire on permafrost soil appeared in the media in the fall and I just see it as an increase in understanding of the importance of forest fires and I think as scientists , we have to continue the rotten Vision by maintaining some of our global networks where We are trying to build a panboreal perspective of these important reservoirs and here I just want to emphasize that 70% of the terrestrial Arctic is in Russia, so we really need to restore diplomacy scientific as soon as possible and the need now is greater than It's always okay, so the last thing is to think a little about some designs or directions that involve both humans and nature, and you know, this is a heavy lift for someone like me, who entered this field to be in nature. pulling plants out of the ground in natural systems, but I believe cultural change is possible.

There is a cultural shift for empiricists who study natural systems because, in addition to empiricists as experimentalists, we have the tools to think about where, as Terry said, we might have levers. socioecological systems, so I'm just showing you some of the more interesting things that I think are happening right now. Here is first my Russian colleague Sergey Zemoff, who has been talking for several decades about the Pleistocene Park, the introduction of husbandry and grazing of animals that compress the snow in the winter, which decreases winter insulation, so summer heat is lost and could potentially keep the permafrost cool and stable.

How this will expand is anyone's guess, but it's still an example of a place where, as environmentalists, we are thinking about the levers we pull. could exert on this permafrost fire climate warming system the second is thinking about fighting the fire to keep boreal carbon in the soil this is a work by Carly Phillips and Brendan Rogers at the Woodwell Institute The current attack and suppression of fires in Alaska and Canada really focus on life and property. What if we extended this to carbon? By suppressing fire, we could affect old carbon by keeping it on the surface longer and maintaining that insulating layer in the permafrost soil.

I think this is another really interesting idea for further exploration and experimentation. interested now in engaging the fire suppressive effects of deciduous trees to engineer what we consider to be living fuels. hundred-year fuels for rural communities. It is the correct scale of processes. to protect rural communities that are at increasing risk of loss of property and life as fires increase across the landscape and then the last thing I like to think about is directing the regeneration of boreal forests after the disturbance. You know there's a whole forestry industry in both North America and North America. Eurasia that focuses on changing the composition of forest stands, well, what have we thought about changing the composition to dampen fire in the landscape and get some of those cold benefits of the change to deciduous species?

Reduction of fire activity. Increased carbon storage and other kinds of social benefits that come from some of these Florence, okay, so just to summarize, I've shown you that climate-sensitive disturbances are accelerating changes in Arctic and boreal carbon. Dynamic perturbations that are outside the historical range of severity are triggering changes in the thresholds we know for future permafrost emissions. Carbon, which is really the big global tipping point, really depends on where we're going with our climate change path and these cascading effects that I've described and ultimately I like the idea that we need to invest in broadening our vision, But we also need to face the challenge of thinking more creatively about how we can use our ecological understanding together with social understanding to drive these systems to design new systems that have elements of feedback and cascades that are desirable and that achieve some of those values ​​that Terry you raised in your previous talk thank you, thank you Michelle and I like the overlap between the two talks we just heard.

We have about 10 questions and we'll probably have time for two or three of them before we move on to the Great Plains. first the one who has gotten the most votes and please all of you go to solido and vote on a question if you really want to hear it discussed in the next few minutes one of Kristen asks when trying to change social norms what strategies does Terry use I suggest addressing the misinformation and disinformation and I would open it up to you two if you both have comments on that, but we'll start with Terry Foreign, that's a good question.

I don't have a simple answer for that, it seems like there's one thing that What the scientific community can do very effectively is provide information that is compelling and, uh, also provide information that relates directly to the solutions so that people see the potential benefits of moving towards sustainability. Thanks, Terry Michelle, do you have anything you want? Add to that, yeah, I just thought I was thinking that there's language that's used to describe well, for example, the permafrost carbon feedback, the methane pump, for example, or the compost pump, um, and I think scientists have consistently rejected that, um, and yet.

It's still making headlines, so I think it's something really interesting to think about. Maybe the scientific message is too subtle and maybe a little boring. How can we overcome that to really capitalize on people's attention? at the same time not not creating, you know, a climate of fear about the future, yeah, I guess that's my answer, thank you and I think about this quite a bit too. I'm doing a senior seminar right now and I've invited Shane Hanlon from agu. to come meet with my class, um and because he works on scientific messaging and how to tell the story in a way that engages people and helps them understand and combat misinformation, so I highly recommend him, he writes the science blog from plain English to agu, let's move on to Suzanne Smith's next question.

I'm blinking, she says, I'm remembering every time travel movie I've ever seen. We interfere even slightly with things that happen. Creates unintended consequences. It is not interference to create. Good results are also likely to generate unpredictable bad ones. Would any of you like to address this question? I think that's always a risk and that's why we need to keep our eyes open if we're thinking about strategies for transformation but not doing anything. It also has unintended consequences that can be at least as bad as taking any action. I really like the kind of approaches Michelle described for managing wildfire risk.

These are things that are based on observations and experiments and have a lot of evidence behind them. Thank you. you, um, I wanted to point out that some people are putting very good comments in the chat on this earlier topic about the messages, um, so thanks for that response, Terry, we'll have time for one more question, so now let's go to one of um Lynn tells a very dramatic figure. I think she is referring to Michelle's work here that she shows the distribution of wildfires just to better understand the map. Are these fires anomalous relative to the normal occurrence of wildfires?

They're sorted by ecosystem, so they eliminate lower latitude wildfires, so Michelle, excuse me. that would be for Michelle, okay, at the beginning of the talk I showed a slide that came from Brendan Rogers that was about the isolation of real and arctic wildfires and it showed an overlay of fire activity over several years over more than a decade , so it's just showing the footprint of fire in this high-latitude landscape answers the question. I think probably yes. Thank you for that and we are. Now we will go to the Great Plains and set up here for our next speaker.

Our next speaker is Dr. Craig Allen, professor at the University of Nebraska-Lincoln. Hello, can you see my screen and hear me? If we can. Thank you for the opportunity to speak today, especially about the Great Plains, which tends to be seen as a flyover in a lot of these discussions, so I'm happy to represent the Great Plains, so I'm Craig R Allen, director of the Center for Resilience and Agricultural Landscape Work at the University of Nebraska and Professor in the School of Natural Resources I work within the realm of resilience focusing on both theory and application.

I would like to give a brief greeting to see us transport the father of Brazilian science who died during the pandemic not from covid but during that very influential period and much of this work. I would also like to say, for the love of Gordon, that there is another Craig Allen out there, Craig D Allen. and I both work for the USGS at the same time, we're both retired, we joke about co-authoring papers just to confuse the powers that be, but we've never done it, and one last housekeeping point relevant to maybe climate, but there's more weather here where I'm in southeastern Nebraska, we haven't had significant snowfall over two inches in two years, but right now we're in the middle of an ice storm and we'll be hitting two inches per hour of snowfall shortly.

I mentioned it because there tends to be a threshold on my internet connection coming from a water tower 10 miles away, but it's been holding up fine at this point so I don't see any problems. I'm going to address the turning points in the Great Plains by focusing. In two particular examples, one in which the tipping points are driven by a spatial process that is contagious and is affecting all of the Great Plains and grasslands globally and the other example is river-based and is an example in the that the thresholds have already been largely exceeded. I'll summarize it briefly When discussing some of the other possible turning points in the Great Plains, the Great Plains are a grassland biome.

Grasslands are highly threatened from a number of sources, including land use change driven by agricultural human settlement and also alteration of some of the key driving processes for maintaining grasslands, particularly fires, in this case I want to focus on tree invasions, a global phenomenon in grasslands, whether in Mongolia, Australia, or the Great Plains of the United States, but for this presentation I would like to talk specifically about the iconic and iconic sandhills of Nebraska. Largely intact grassland sandals comprise much of Nebraska's land area of ​​approximately 20,000 square miles in our grass-covered dunes. Yes, when European settlers first arrived in the Sandhills, the Sands Hills were largely bare land.

There is an author Parker who explored the Platte River and into the sand hills and across much of the Northern Great Plains in the late 1850s and described the sand hills as dominated by bare land with fairly sparse grass. dominant use with bison replacing cattle railroads were established, and railroads and other ignitions often created devastating wildfires that eliminated dune grass. Settlers recognized that moving dunes are an alternative stable state to sandals. The dunes actually moved and the Sandhills moved as recently as 800 years ago, BP's response to the recognition of this possible alternative stable state should inhibit wildfires and reduce herbivore pressure; in fact, sandals today are much more dominated by grass than in the past, like Aldo Leopold, who actually recognized Titan toes in the grasslands of New Mexico in the 1930s.

Sandhills uh, settlers were and are aware of the potential undesirable state of the dunes for the system and have managed to move away from it, as Leopold wrote in 1933 in Conservation Ethics to cite a public domain that was once a velvet carpet of buffalo grass and grass, now an unlimited waste and a snake ofJingle Bell. Bush and Tumbleweed to the impoverished to be accepted as a gift by the states within them, which is why, because the Ecology of the Southwest was on a trigger, so Aldo recognized very early that the grasslands had these points tipping and resilience.

What I was describing at least was low crolite, in fact there is a species of plant almost endemic to the sand hills, the blowout penstemon, which requires the name to suggest blowouts which are depressive sand driven by the wind or uh, wind blowouts in the grass, making a depressive sand pit, so to speak, and this is the habitat of this species now, this species is now rare and endangered, it is a testament to the success of the settlers and their management away from critical turning points that could lead to an alternative emergence of a Blowing Sand State for Sand Hills, which is and was seen as a very undesirable alternative to destiny.

The potential for a dune State. Los Angeles historically dominated. Land management activities. Grazing pressure remained and remains very low. The fires are suppressed and stopped and are seen with quite a bit of fear. partly because wildfires were so devastating historically. Keep in mind that this is a very large area of ​​land at approximately 20,000 square miles and one with such a low recovering population that it would be considered the frontier. If in 1890 the population was often less than six people per square mile, wind erosion is the process combined with vegetation removal and overgrazing, perhaps combined with fire, that threatens to create an alternative stable state in the Sand Hills. transferred by early settlers, at least when it is the constant presence on sand hills and which can endanger Windbreaks for both people and livestock are widely used due to low rainfall and sandy soils.

Clearly, only one species is suitable for windbreaks in sandals. Eastern red cedar, a previously rare native species that happens to be one of the most fire-susceptible species in the north. American windbreaks are now ubiquitous on sandhills and can be extraordinarily extensive and long. I think a mile, unfortunately, these windbreaks literally introduce seeds of change into the sandhills. Eastern red cedar matures in about seven years and adult females can produce millions of prodigals. they fall near windbreaks and are also spread over longer distances by animals, mainly birds, so there is a bimodal distribution. Wind farms provide an important ecosystem service.

I can attest to having been to Sandhills and working in Sandhills, especially in January. Windbreaks are really effective in reducing impacts that last for years, but as an ecosystem service windbreaks are local and short-lived for a long time, longer time scales, they become sources of invasion on the same ranches where they are planted. to protect and spread to larger spatial scales. has spread to adjacent areas that may not have eastern red cedar present in the first place, other than windbreaks as a propagule. Source Eastern red cedar has been spreading from the southern Great Plains and eastern Nebraska, such as Nebraska, which is currently losing about 40,000 acres a year due to this emergence of a stable state dominated by trees that takes over cedar dominated states reduces grassland productivity, reduces livestock production and once established cedar forests exhibit quite strong hysteresis As a side note, it was mentioned earlier about early warning i.e. early warning indicators, and then in processes like tree invasion or any number of spatially contagious processes that can lead to the emergence of alternative stable states, mapping that process and determining its philosophy can actually provide decades of early warning before For regime change to occur, simply eliminating the theater is insufficient to restore grassland herbaceous seeds. banks are lost, soil properties change and fires are much more intense and cedar, compared to grasslands, the carbon stored in cedar may be more labile than that stored in grasslands.

Cedar is an undesirable alternative regime in the Sand Hills, which came as a surprise to ranchers. avoid a different alternative regime move the dunes Surprise is often the reaction to the emergence of these alternative stable states, although the details differ. Similar processes are at work in the Great Plains and grasslands globally. Efforts are currently underway to reduce the spread of cedar in the Great Plains. It is more important to put more fire to restore the dominant driving process on the land to limit further grassland loss to invasive trees. I could switch gears now and talk about another ecosystem in the Great Plains and really focus on Great Plains rivers, which again have The application to many river systems globally, especially those with snowpack-driven flows, is will focus on the Platte River shown here, which runs through Nebraska and originates in the mountains of Colorado and Wyoming for the south and north forks of the river and is largely watered by snow.

Swells and floods from the belt and springs historically kept the river quoting a mile wide and an inch deep. These floods maintained bare sandbars critical for the North American population of Sand Hill Cranes and under other species such as whooping cranes and Lease's plovers. To a lesser extent, constant flooding was a threat to early settlers and fire-like agriculture and as this happened in most of the world's rivers, efforts were made to tame the river and reduce its low variability to flatten the height of grass, this also meant dams. built to provide rural electrification and diversions into canals for agricultural use, these efforts were successful, but with the surprise of causing our gene by eliminating the primary driving process of river systems, these spring floods, the plant is now an alternative regime, A turning point has already passed. characterized by a hydrograph less variable in size.

Banks, islands and coasts that have become vegetated first by native herbaceous vegetation, then by invasive herbaceous vegetation such as phragmites and finally by woody species such as trees, making the change highly hysterical. The river is now in an alternative stable state. but it is in many ways desirable for humans and agriculture floods are now rare. Water is ecologically available for irrigation, although the change in regime is highly undesirable. Roosts, cranes, turns and miles require bare sandbars for roosts, which have been lost due to the loss of a drip system. In the process, the exception is a 50-mile stretch in the central parcel where the river is forced to imitate its previous state.

Trees, herbicide-treated herbaceous vegetation are cut down from all-terrain vehicles, helicopters and other means, and sandbanks are plowed, in fact, tractors get in the middle. the river and the clouds The tipping point has been passed by expensive and constant management keeps this 50 mile stretch a ghost of its previous state is this really possible or necessary due to the presence of endangered species and a plan of reclamation that was implemented after a dozen years of negotiation when the Kingsley Dam was relaxed, relicensing the last dam on the Platte River, the reclamation program to date, which in the park helps keep this central platinum in its former state, this costs more than 200 million dollars today, so currently the plant exists in two states, one self-organizing and largely desirable for humans and agriculture, but ecologically undesirable and a stretch 50 miles that a coercive state exists that is ecologically desirable but perhaps or arguably less desirable to humans, many rare habitats like this example are maintained solely through coercive actions by humans, meaning that cessation of management given the cessation of management The river would quickly move to that alternative forested and undesirable state abroad.

I would like to briefly mention the cascading telecoupled effects in the Great Plains and other Great Plains tipping points. They are not comprehensive changes at all, for example, in grasslands. The cascading drop or a couple of declines in Sandhills meat production leads to deforestation in the Amazon. The system, as we heard yesterday, with its own critical tipping point and the agriculture-dominated Platte River, leads to an over-fertilized Gulf of Mexico and hypoxic dead zones. present in all social or pre ecological systems of the Great Plains and are present in both ecological, economic and social subsystems. There's another example: Many lakes in Nebraska are issuing warnings about impending tipping points in which lakes are at risk of becoming overtaken by toxic algae that mimic what we do.

We are seeing in Lake Erie and in the Gulf of Mexico off Florida, thank you, the ranchers in the Sandhills are furious and the average age is now about 60, so perhaps we are close to a demographic tipping point and extraction of groundwater has been the ones we have talked about before in nitrogen inputs at many scales also have critical tipping points than those of the Great Plains. Turning points also occur in markets when costs can exceed profitability. All of these changes can cascade to affect the social ecological systems we inhabit and are inevitably globally telecoupled. as well as at a local level, so it is important to identify these critical tipping points, although perhaps we often anticipate the incorrect alternative stable state emerging and of turtles critical tipping points are identified in some cases it is possible to manage outside of these thresholds and coercion can maintain desirable states. where self-organization is lost, but it is costly, temporary and difficult and most likely only a short-term holding pattern solution.

Thanks Dorothy. I think so, thank you. I didn't click on that enough. Thank you so much. A quick question from Before we begin here we have 10 minutes for questions. You use the word coercion for that 50 mile stretch of the platform. Is it synonymous with restoration or did you deliberately not use the word restoration? I deliberately do not use the term restoration because in my opinion, restoration should restore the um stop organizing the processes without the processes being restored. It is not restoration, it is really gardening, so to speak, and as long as we do not manage annually and again only tractors in the rivers, as soon as that happens, even for a season, the river becomes uninhabitable for sandhill cranes and this is the entire north.

American population, almost the entire North American population of sandhill cranes and whooping cranes that grow through this bottleneck in the north central flyway, where the entire flyway narrows down to this 50 mile stretch right in Nebraska, so The Platte River is a critical stepping stone, and in fact, its use by Luther would create another tipping point, perhaps in the sense that the distances between suitable roosting habitats might be too distant for these types of interesting species, for example. which is not really an alternative stable state unless constantly coerced, yes, that's why I call it a ghost of the past regime is being imitated and we see the same parallels in all kinds of systems, even, for example, in health mental, where we can force, for example, bipolar disorder to imitate a healthy state, but as soon as you stop the interventions, the less healthy state emerges, we see that also by maintaining the neutral circle of lakes in the boreal forest of Sweden , we say that we are coating imitates a neutral state as soon as the liming has started or has spread, the river returns to the acidified state thanks, we have a question from Alessandra conversi says that cedar is now an undesirable regime compared to grasslands.

I think, quoting you, she said this is confusing when I look at it in the context of the big picture, there are advocates of planting millions of trees to offset CO2 emissions, yes. And in fact, last year, maybe two years ago, a group in Switzerland published a scientific paper claiming that afforestation of previously deforested areas would be a solution to climate warming. Those of us in places like Nebraska reacted quite negatively. To that and the question of, I guess the idea would be that a lot of carbon would be stored in these forests, but you could say that the carbon, if we forested the Sand Hills, would be in a tree with atree like eastern red cedar because of sandy soils. and low rainfall, I will grow a lot more there, there is a species very prone to fires, you know, most of their biomass is above the Corona, unlike the biomass in the grasslands, so you could say not we would have a long-term positive impact on global carbon sources and, of course. it would absolutely ruin the economy of the entire state of Nebraska, thanks from Mike, what tipping points do you see socially, particularly in agriculture? um, interesting, well, and one and I thought about it a little bit as social scientists.

I mean, there are certainly aspects like I mentioned that in the ranching era there is a real concern that the average age of ranchers here is almost 60 and what's going to happen when those people actually get out of ranching, um and other than that, I don't think I have a good answer except that I think there are a number of social tipping points in these systems, thanks from Kristen, what strategies could be used to reconcile the desirable state for humans of rivers with the ecologically desirable state? It's possible? to do that reconciliation right, there is a big federally funded restoration, not a recovery, adaptive management, recovery of the plan for the plant that helps maintain that Central State, there is another shadow governance group, um, that has emerged .

I am part of a vision for a green economy. Sound Plant River has been working with the public in areas like um where there are choke points in the river that impede the flow and we've been working on surveys etc. to determine opinions and attitudes towards the river and in fact we received the results yesterday and I heard them yesterday afternoon and it appears in places where I am a little surprised that the river in its natural state is actually highly valued and in areas like Big Bend, the 50-mile stretch that still has bare sandbars and attracts cranes.

The cities or towns in that region have really focused on that in terms of ecotourism and really taken advantage of it and since the economic benefits are derived from the river beyond agriculture, I think the argument is heard better and is more compelling that maybe we should restore it. This river is in a more natural state of self-organization than is allowed, since people do not like floods and, in fact, floods affect so many people that experiments on the plate have been limited to very small increases, but those ideas that we heard before about um, you know, be careful.

Removing ourselves from areas prone to flight, etc., could help and get us to a place where the ecologically sound Plant River can also provide these benefits to humans in terms of agricultural productivity and water, and that could very naturally lead us to Another question that just came in from Rich Bloustein is: Please offer what resilience would look like for rivers and grasslands. You can choose one if you want, but if resilience is indeed the goal, I think there are two things with resilience and The way I see resilience is real, two components, one is the greater dynamics after a disturbance or one which can be captured by recovery, i.e. most shocks do not cross a critical tipping point, but for me the key aspect of resilience is the presence of those thresholds and alternative stable states, so there is a normative aspect and what state is desired and in a place like Sand Hills that grassland state is very desired and I think restoring fire to the landscape when we do experiments with that and get the public perception of fire changed from one of fear to one of you know that a beneficial ecosystem service can keep that system in a resilient state, meaning that it is self-sustaining and believes it needs little intervention over longer periods of time.

Yes, I kept thinking while they were talking about the image we saw yesterday that shows the native plants and grasslands very entrenched compared to those of agriculture, wheat. I think that was such a shocking disconnect, yeah, and also one and uh, and the reason why forestation ideas are in the sand pit or taken quite negatively here, at least in the Northern Great Plains, well, thank you very much, now we're going to get ready for our break room, so thank you Craig for that wonderful break, ours is that right, right, okay, so everyone. Well, we're going to have a 30-minute breakout room session and the last five minutes of those 30 minutes will be used for repertoires to write down their key points in a Google document.

You can choose the room you want to go to. for the different regions that we've talked about today, so in a moment we will have those breakout rooms ready here, hopefully, we will have the hope of having natural and social science scientists in each room and, if you go to a room and it's quite full and you have interest in other geographic areas, um Phil, welcome to join another room that might be less crowded, we don't know how this will turn out as we're doing this in a more uncontrolled way today, so I'm going to sign out here and let someone else take over the groupings of the group rooms and like I said we have thank you foreigner foreigner foreigner foreigner foreigner foreigner foreigner foreigner thank you foreigner foreigner foreigner foreigner foreigner foreigner foreigner foreigner thank you foreigner foreign foreign foreign foreign foreign foreign foreign foreign foreign foreign foreign foreign foreign foreign foreign foreign foreign foreign foreign foreign foreign foreign my responsibility uh I'm Tim Linton and you heard a little bit about me yesterday.

I think it's my responsibility to just um in the remaining minutes we have a call to the different working groups to report here to the plenary um I'm not quite sure what happened, but we all did a second little round trip in a little time warp there. Stranger, they may be in your group and have not returned. You are passing between parallel universes. I was going to say maybe he's in hyperspace or something. Let's give it one more minute. There's Tim. I see. Hello friends. Yes, they sent me forcibly back on the run. room when I was trying everything he did, it was true for everyone, okay, then, then, beer, okay, so my job is now with a little less time than we had, um, calling the different groups of I work to report and I was the moderator of the Arctic, um, so maybe I'll try to briefly summarize a big group discussion in the um, in the virtual Arctic.

Okay, so if I had to take away three things, first, evaluate tips. Hotspots and cascading risks in the Arctic. There is a strong theme in the group that we need to look at both the natural climate and ecological systems and the social systems and communities of the Arctic in a holistic way and their potential tipping point and, um, cascading risks. We have noted several of them, but as a practical step I think we had broad agreement that it would be worth redrawing a map and a list of possible tipping points in the Arctic related to climate change, but that would extend beyond the physical climate.

The ecological and the social, particularly for indigenous communities that are more exposed to overturning. When we turned our attention to the kind of transdisciplinary research opportunities, there was a clear message that we need to work in co-production with other Indigenous knowledge systems. as well as scientific epistemology, uh, any kind of transdisciplinary research effort that seeks to, I don't know, better manage the risks that those communities are exposed to from the tipping points in the Arctic, but also that there is a co-production of any of the opportunity space of what Terry referred to earlier as positive tipping points for change in the Arctic, so it was really just two points, but those are actually the two dominant themes, so I'll do that and see if anyone more of my group wants to add something to that. quickly, but if not, with the clock ticking, I'll turn to Kristen who is the US coastal moderator.

I think so, thanks Tim. Oh, our discussion focused on a couple of areas. A big topic was the message and communication of science. results um and not the communication of it, so we are expressing it in terms that are very meaningful to the communities that these will impact and um and also that those involved, the community members interested in the regions are part of the process all the time, so knowledge co-production seems to be an essential piece of almost all regional studies and is something that needs more attention. Another key point was to analyze how to include uncertainty, for example, about sea level. increase significantly again so that both scientists and stakeholders, decision makers can better understand how to include uncertainty or how to include how to represent what is unknown, if something is high risk but we have a lot of unknowns about That doesn't mean that it is low probability, so how to represent this and communicate it so that there is less confusion and it does not become an obstacle to decision making?

And then a final point would be to think about the transdisciplinary nature. I would be thinking uh there's a lot of interest in natural nature or should I say nature based solutions um to help with that would have ecological and human benefits on the coasts and there would be a lot of transdisciplinary opportunities um focusing on that in the future so I'll stop there. and I'll pass it on to Michael, yes, our American map of the West. I think so, so our group spent a lot of time talking about some really powerful feedback loops that keep repeating themselves in our discussions, so we started with a discussion about the impact of snowpack and the cascading effects from there, that you know that snow cover affects energy supply, power generation, water supply, agriculture, recreation, ecosystem health, etc., we relate to this, we also talk about drought and stress water and this water stress exacerbates fire exacerbates carbon emissions exacerbates drought and so on in another feedback loop uh extreme heat and surface water temperatures from wildfires all of these things continue to come together when we talk about research opportunities a couple of things that We thought it was important to focus on the regional centers, that focusing on the region as we are doing here now is important and useful to think about what investments we should make in infrastructure, how we should use our funds and uh. then we also talked about uh Geo health and the Nexus of water, energy and food, we'll leave it at that.

I'll hand it over to Simon and the Great Plains, okay, thanks Mike, yeah, just a minute left, I mean, we in terms of The Tipping Points themselves, we went back over what Craig talks about about the Nebraska River. Sandhills Platte, but we also added the Ogallala aquifer and groundwater, nitrogen thresholds in the river system, and precipitation thresholds for rainfed systems to the list. agriculture in terms of research opportunities or priorities. I think really the key word that came out of our group was telecoupling teleconnections and the importance of bringing together groups of researchers and approaches that are able to study teleconnections between the Great Plains region and the impacts and tipping points elsewhere. from the US and beyond fantastic.

I'll thank you all for your participation today to the speakers for some fantastic provocations and encouragement, it feels like there's a New idea right at the end of having some kind of regional tipping point. management or impact centers, which is something great, as the clock ticks down just to tell you that oh yeah, I haven't given Margo the floor to talk about those that are online, I should have. Okay, overseas, it's actually going to be. I handed it over to Jonathan, ah, Jonathan, okay, I apologize, don't worry, I'll just highlight a couple of things that appeared online.

They covered all regions, an example of airplanes, how do we sustain the economy? How to sustain economies on the Platte Rivers without reducing grazing and reduced use of floodplains. Are there floodplain compatible species that have economic value? It was a question that was raised. Another question that was raised with some ideas is to identify how to identify possible water and vat storage areas. volcanic zones, depleted aquifers and things like that through satellite and sensor based monitoring and through the use of coupled modeling involving things like downscale gcms regional precipitation groundwater model river model flows snow volcanic storage and water uses, so very coupled modeling efforts or the things that came up in that bright region, thanks Jonathan, so I hope you're hooked on the workshop now and we hope to see you at our lasttomorrow, where we will begin focusing on interdisciplinary or disciplinary research priorities. and opportunities at turning points, very good continuity from today's summary.

Thank you all for another great day. I hope to see you tomorrow. It's actually a fine afternoon or evening from the UK, but it's probably a fine afternoon in the east. coast and happy lunchtime and on the west coast, all good