[00:00:00] Bridget Scanlon: Welcome to the Water Resources Podcast. I am Bridget Scanlon. In this podcast, we discuss water challenges with leading experts, including topics on extreme climate events, over exploitation, and potential solutions towards more sustainable management.
So I'm delighted to welcome Kate Brauman to the Water Resources podcast today. Kate is the Deputy Director of the Global Water Security Center, which is part of the University of Alabama system. This center focuses on translating water science for national security. Previously, Kate served as an AAAS Science and Technology Policy Fellow in D. C. for the Department of Defense, and before that was at the University of Minnesota, where she was a lead scientist on the Global Water Initiative.
So Kate has a long background in nature based solutions, and that's going to be the focus of the podcast today. And so maybe, Kate, you could start by describing a little bit the work that you're doing currently at the Global Water Security Center.
[00:01:09] Kate Brauman: Absolutely. It's really a pleasure to be here today.
And I love talking about water. So I'm excited to talk to you today. At the Global Water Security Center, we're really interested in taking all of the great science that's out there about water and nature-based solutions and all kinds of things and really translating that for decision makers. And specifically, we're working with folks at the Department of Defense.
And so trying to help them understand how well water and environmental information can really play into the kinds of security questions that they are interested in and that they are looking at. So we're not doing disaster response. There's already some great organizations out there that do that.
We're trying to look a little further out at kind of a strategic time scale to try to understand how changes in water might affect security. So as an example, we did some work looking at Spain at the Catalonia region, which this summer was coming up on an election and, also was in the middle of a very big drought. And one of the things that has happened there in the past is that people have used discourse around self-management of water resources to really push forward the conversation about Catalonia and independence. And so what we were able to do was look at what are the water levels looking like in reservoirs right now, what are the forecasts for rainfall, and how might the actual biophysical situation play into some of these other larger themes and exacerbate some of them.
And so what we saw looking at the data was that there was going to be really low reservoir levels, and that could play into this conversation. It actually turned out that there were other pieces to the puzzle, so this was not the one that was the overriding factor in the election. But we certainly did see that water again and self-rule of water came up in part of the discourse about Catalonia independence.
[00:03:19] Bridget Scanlon: Well, that's fascinating. And so that is really challenging having to bring all these data together, satellite data, modeling data. And I understand from our previous conversations that you're going to be hiring a number of data analysts. And so you will certainly need those to fuse all these different data sources and make them talk to each other and generate something in short order, I guess, within one or two weeks to respond to questions that you get from the intelligence community. So that's going to be really exciting. So, as I mentioned earlier today, we're going to focus on discussing nature-based solutions, which you have a long history of studying and you have published many extremely valuable papers on.
We will try to define different terms related to nature based solutions, look at applications of these and what they can and cannot do, and the different roles of nature based solutions, including regulatory function or providing material and non-material services and then give some examples of where they have been applied in different regions globally and an idea of maybe how effective they have been and then compare with traditional engineering solutions and what we might see as their role going forward.
So I realize that's a lot to cover but maybe we can start to determine if you can define nature based solutions and where the term originated and that would get us going.
[00:04:48] Kate Brauman: Absolutely. And it's a great question because there are a lot of definitions of nature-based solutions. And it's a pretty encompassing definition.
So, one of the places that nature-based solutions get talked about really the most is the IUCN, the International Union for the Conservation of Nature. And they've really been pushing a definition that really talks about leveraging nature, the things that ecosystems do anyway, and taking advantage of the positive parts of that, of the things about that we as people are really interested in so that we can optimize infrastructure. We can think about maintaining the delivery of different kinds of benefits that we're interested in, what that means that can vary really, really widely. So this can be everything from reforestation, so really big scale tree planting, to managing farms with fewer pesticides, to composting toilets, and green roofs in cities.
So there's a really wide range of things. So when somebody says, gee, I think nature based solutions are great, the first thing you should say is, oh, what exactly are you talking about? Because there are a lot of really exciting things that are happening with nature-based solutions, but because it encompasses such a wide range of things, it's very, very hard to evaluate, or kind of take, assess in a serious way unless we're specific.
[00:06:27] Bridget Scanlon: And I guess the term originated in the climate community to try to mitigate climate change and, and so they were promoting planting trees. Is that correct, Kate?
[00:06:38] Kate Brauman: That's my understanding. I think people have been talking about the value of nature for time immemorial and there have been a whole series of kind of different ways of talking about the benefits that nature provides and how we harness them.
And so nature based solutions, I think, has really come to the fore because of interest and natural ways to sequester carbon. So really through tree planting or forest protection, there's actually a program that's part of the UN Framework Convention on Climate Change (UNFCC) called REDD, Reducing Emissions from Deforestation and forest Degradation.
And part of the key for nature based solutions, especially as the way the UN talks about it, it's quite focused on not just the biophysical impact, but also the social impact. And part of that is because pretty early on, at the beginning of some of this investment in forest programs. There were good things that were forced being planted and protected, but there were also bad things because of issues about land tenure and who had land rights and who was actually getting paid and whose livelihoods were perhaps being affected.
So if you've been cutting down trees for firewood so that you can cook your dinner, and then somebody says, no, we're not cutting down trees, we're protecting the climate, there are winners and losers in that, in that equation. And so, as REDD has evolved to now be RED and in general, as I think folks have started thinking and talking more seriously about nature based solutions, there's been a real emphasis on thinking more broadly about, What are the implications of these in both biophysical and social ways?
[00:08:25] Bridget Scanlon: Right. And you often, I often saw on the road, maybe a long time ago, you'd see bumper stickers saying plant a tree, save a forest or things like that. And then when I was looking into what was going on in South Africa after apartheid, so I think they united the land and the water programs within the government. And so if you wanted to plant a tree in your yard, you had to pay more because they recognized that it used more water. And so this is kind of strange for us because we always thought planting a tree is inherently good, but as you just mentioned, there are tradeoffs with everything. So there are tradeoffs on the biophysical side versus the social side and that we need to be aware of those.
And I think another thing that you mentioned recently was ecosystems, people don't make water. And since we're focusing on water today, I think it's important to recognize that maybe, do you think a lot of people have the preconception that ecosystems can make water or that is an underlying theme that they might have, or, or what are your thoughts about that?
[00:09:29] Kate Brauman: Well, I think a lot of times people understandably aren't spending a lot of time thinking about exactly where their water comes from or how it gets there. And so one of the things that we see, especially in the United States, but actually in many places in the world, is that serve as water sources often are forested, and that can be true for a couple of reasons. if we're getting a lot of water from that watershed, it probably means it rains a lot there. So it's a good place for forests to grow, so forests have naturally grown up there. It's also true in the United States and in lots of other places that we have made an active regulatory moves to protect those watersheds and not allow anything except for us to be there because when we plant crops and we tell the soil that you can have runoff of soils into your water if we're putting herbicides and pesticides as well as nutrients onto farmlands that can get into the water.
Yes. We're leaving these as forests, then we're not putting pollutants into them, and we're not getting pollutants out of them. And so, there's lots of places where forests are indeed very important parts of the ecosystems that provide water, but it's not that the forests themselves are providing water.
And I think when we think about making active interventions in places, we really have to think about then what's there already and what are we thinking about putting in there instead, especially because, as you mentioned in South Africa, and actually there's been some really nice studies here in the United States and the Southeast where I am that have looked at the actual tradeoff between forests and water, where you're getting actually more evapotranspiration from forests, from trees, than you would from grasses. And so, you see lower levels in streams, you see lower availability of water downstream, because that water is getting diverted by the forest into the atmosphere.
[00:11:39] Bridget Scanlon: Right, and I guess that really points to an important role of ecosystems in partitioning the water at the land surface between evapotranspiration back into the atmosphere, or runoff, as you mentioned, forest reducing runoff and sedimentation downstream, and then groundwater recharge.
So thank you. That partitioning then is really controlled a lot in part by the vegetation and the soils and other things. And so recognizing that and understanding how water moves in the water cycle there is important.
[00:12:13] Kate Brauman: And that's, I think that's, you've hit on the key there that sometimes people talk about this as a regulating service. It's changing the flow of water, but what's I think really important to remember is we can change the flow of water. We can divert more or less to the atmosphere. We can divert more or less into groundwater. We can divert more or less into surface flows, but we're not going to make more water.
[00:12:40] Bridget Scanlon: Right, right. We can change the partitioning then, but we're not going to change the laws of physics.
[00:12:46] Kate Brauman: Exactly. It's frustrating, I know.
[00:12:51] Bridget Scanlon: So in one of your papers, you really nicely described the different roles of nature based solutions. And I guess basically what issues you're trying to solve with nature or changing nature and regulatory you just mentioned and material source purposes like energy production, biofuels and food and feed and water impacts. And then also nonmaterial purposes like spiritual or aesthetic. Maybe you can describe those a little bit, Kate.
[00:13:26] Kate Brauman: So there are tons of benefits that we get from nature. And those are called all kinds of things. They've been called ecosystem services. They've been called nature's contributions to people.
Sometimes I just call it food. Really thinking about what happens in the world, and not just the wild world out there, but the managed world around us, that we, as humans, and the rest of the world that we care about benefit from. And so, food is a really obvious one. They are the plants, we eat plant parts, and then we eat animals that eat plant parts.
And over time, we've found ways to grow those plants differently so that the edible parts are bigger and faster and tastier, and culturally appropriate, that we actually like them. It's not just that they have nutrients, they have meaning for us. And so we have bred plants in order to have more of that, and we have planted ecosystems as agricultural fields so we can have more of that.
Similarly, water flows through the environment and it both picks things up from the environment and it puts things into the environment. And that is both good and bad. It doesn't really have value until there's a person to value it. The quality of water is just a description of what happens to be in the water.
The value of that water quality comes from, is it safe for me to drink, or my family, or my pets, or the animals that I care about? Is it tasty? If you ever go to the grocery store and you get distilled, a bottle of distilled water, that's very, very clean. So in some sense, it's very high quality. It also tastes pretty bad.
You actually want stuff in your water to make it taste good. and this is very valued. There's not a right answer. There's the way that we use water. And so what this whole framework really looks at is what is it that we're, that we want and how are we managing the environment to get that and it's not just water or just food.
It's both of those and it's also energy, it's looking at how if we're managing the land in some way, what is that doing to pollinators and how does that change both the food that we get and the flowers that make us want to walk around out in the wild that make us happy to be here. And so thinking about the whole system and how changing the system changes those flows of benefits, the different benefits and to different people.
[00:16:15] Bridget Scanlon: Right. So it's a huge topic, really, when you think about it comprehensively. So the regulatory aspects would be impacts on water quantities, water scarcity, and then, as you mentioned, the quality aspects and deforestation and things like that, and hazards, droughts and floods, trying to manage those. And then the food production, I think we saw the biggest impact of changing land use when we expanded agriculture early on.
And more recently in places like Argentina where they're still continuing to expand agriculture. So again, we changed the partitioning of water at the land surface in many regions. And then we changed from forests or grasslands, deep rooted systems to shallow rooted crops with fallow periods. So we reduced the amount of water going back into the atmosphere and we increased the amount going into the groundwater oftentimes.
And so, for example, in Australia, they ended up with dry land salinity issues, Southwest U. S. increased recharge, which was okay. Argentina recently talking about all the flooding that they have because groundwater levels that are at the land surface and how they can control that because it's extremely flat plains.
So these trade offs are very important and many of the changes that we've seen in the past were unintended consequences of just, but now we're trying to be maybe more thoughtful about it and with nature based solutions, maybe more intentional in what we do in controlling some of those or regulating some of those services.
[00:17:51] Kate Brauman: Exactly. And that's the key, is that instead of, instead of stumbling into things by accident, frequently being unhappy with with what's happened, it's really trying to think ahead and be proactive about the land use choices that we make and thinking about ways to often just to tweak things that we might be doing anyway in order to get more benefits and less negative impacts from these changes on land use.
[00:18:21] Bridget Scanlon: And I think we've seen that in the last decade or so when there was a big push to produce biofuels from crops, like miscanthus, deep switchgrass, deep rooted grasses, or corn in the Midwest and in other regions globally. And so if we went from cropland like soybeans to miscanthus or switchgrass, then we would reverse what I was talking about earlier.
We would increase the amount of water going back to the atmosphere, reduce groundwater recharge, reduce base flow to streams. So being aware of those things ahead of time and trying to manage them is probably very important when we propose different policies for these things. Exactly. So one of the terms that often comes up related to nature based solutions is natural capital, which is another very broad term.
And I've seen people describe basically natural capital assets as air, soil, sediments, water, and biodiversity. Maybe you can talk a little bit about what they are doing to try to preserve natural capital or to understand it or quantify it and not nuke it with development and things like that, or understand where there are hotspots where they really should either restore it or maintain it.
Maybe you can describe that a little bit case.
[00:19:45] Kate Brauman: Yeah, so I think there's some I think there's some interesting ways to make use of this analogy of ecosystems to capital. And so one of them really is about this kind of use it now and get the benefit or preserve it and kind of live off the endowment. And neither one of those, either in a financial sense or an environment sense, is inherently wrong.
There are lots of reasons that you might want to spend all the money right now, but it does mean that you've lowered your bank account, that you're not going to get that endowment income for forever. And, soils are a great example of this. If we are working soils hard by growing crops that we're then taking the nutrients out of the soil, we're removing the crops and we're not refreshing those soils, we can go for a while like that.
But at some point, newer soils, you really, you take it out the nutrients, you've removed the natural capital from your soils, and then they're just not as productive anymore. And you're not going to have the benefits until you build them back up until you build back up that endowment. And we can think about that in in other ways, too.
We can think about forests and, for example, there's lots of really great things that forests are doing. They're holding carbon in the trees. We've got nice clean water coming out of there because other than a few deer who are maybe pooping in the forest, there's not a lot of nasty things that are getting into the water in the forest.
If we cut down the forest to grow crops again, we've got this trade-off, right? You get food right away and if what you really need right now is food, that's a trade-off. That makes sense. But if we are able to preserve some of these assets and recognize the value of the environmental benefits that are flowing out of them, and for example, find other ways to make sure that people get food so that we can preserve forests, then we can really think about.
We can think about that as natural capital, as an asset that's kind of in the bank, and has an ongoing provision of benefit. Right.
[00:22:07] Bridget Scanlon: I think economists often say, have the mantra, like, use it now, or whatever, and get the economic benefits now. But when you mentioned soils, I think I see a lot of programs these days and papers written about on no till agriculture and and cover crops and trying to restore organic content to the soil to increase infiltration capacity and nutrients into the soil.
So this very intensive agriculture with lots of fertilizers and things like that may not be sustainable in the long term, but trying to look at other approaches to doing agriculture because food production is one of the big purposes of big ecosystem service. and it can also have water implications. So you wrote a very nice article in Proceedings of National Academy of Sciences on the trends in nature's contributions to people over a 50 year period, I guess, 1970 to 2020.
And maybe you can describe what you learned from that analysis, Kate.
[00:23:14] Kate Brauman: Absolutely. But to answer that question, I have to back up a little bit. And I have to give a lot of credit to a lot of people. I had the honor of getting to be involved with something called IPBES, the Intergovernmental Platform on Biodiversity and Ecosystem Services.
It's got some similarities to the IPCC, the Intergovernmental Panel on Climate Change in the sense that the goal of IPBES is really trying to collect and synthesize the evidence on what is happening with biodiversity and ecosystem services. And so, starting in the mid 20 teens and eventually released in 2019, I got to help work on the global assessment, IPBES global assessment, the very first one, where biophysical scientists, social scientists from around the globe came together in a bunch of different teams, there were six different chapters, even within chapter two, which is what I was part of, there were three different sub chapters.
So there was a whole sub chapter on nature. And what are the status of trends of nature? There was a whole sub chapter on nature's contributions to people. So that was what I got to help lead. And then there was a whole section on like, what are the drivers? Why is this even happening? And that's just one chapter.
And even our little itty bitty subchapter, there was a group of 15 of us who were the lead authors, were charged with... The status and trends of nature's contributions to people, all of them around the world over the last 50 years. Go! It was a lot. And there were a couple of things that we found while we were doing this.
As this group of experts came together from really different backgrounds and then reached out to our network, to even more scientists with even more diverse backgrounds, was that the evidence at first really looked like it was all over the place, and part of the reason for that is that people were really measuring and reporting on different things, and it was really confusing.
And so we ended up after much, good nature fighting amongst ourselves, figuring out a way to organize all of this. And that, that I think as much as anything, is a huge contribution of this. Because what we really found is that when we look at what are the benefits that are flowing from nature to people, the thing that I think as people, we tend to think about is like, well, what's the impact on my quality of life? How am I doing? Have I been displaced by a flood? Am I still hungry? What's my actual, like, nutrition or malnutrition level? Am I getting waterborne disease? Do I have to pay a lot of money for water treatment? Nature influences all those things, but so do a lot of other things. And if you actually look at those indicators of quality of life, many of them are going up, even though the status of ecosystems may be going down because of substitutions, because of technology, because of the way people have adapted and are working with those systems to compensate for nature, to work with nature.
And so we started kind of looking backwards. So really thinking about like, well, what's the potential contribution? How much could these wetlands and these streamside floodplains, how much could they filter out of water? If we've got water full of nutrients coming off of farm fields, how much could these different kinds of nature and nature based solutions, what could they contribute?
What's pretty interesting, though, is that just because they could, doesn't mean that they are, because if you don't have a farm field that's inland from that wetland or that floodplain, there's nothing for it to filter out. If you have also preserved your forest, right, inland from that floodplain or wetland, you've got basically clean water that's coming to an ecosystem that could clean that water, but it's not because there's nothing to clean out of it.
And so in that sense, the sort of potential for ecosystems to provide things, which is often what we measure, because it's often kind of the easiest thing to say, Oh, we're going to use land use as a proxy. And if there's a floodplain here, it could be doing a great job. Is actually very different than what that floodplain is actually doing, which is part of the bigger ecosystem context.
But then we also started finding that sometimes ecosystems can really help. Sometimes you've got, something nasty upstream, you've got a wetland, it really is taking out sediment, nutrients, and, if you had sensors all the way along, see that the water coming out downstream had much fewer of these pollutants that we care about. And that it was still full of those pollutants. And you still wouldn't want to drink that water downstream. And if you are just a person who's like, well, so you've got your nice ecosystems, can I drink the water now? And the answer is no. You're experiencing something that's very different than what these scientists are saying, like, oh, these ecosystems are working so hard. But because the environmental conditions are still not great, the impact on you as a person is still like kind of bad. And so what we saw over and over again was that you could measure all of these, and they didn't all go the same direction. And they really didn't all go the same direction for all constituents.
And again, I think, water quality is a great example here. In the United States, there legitimately were rivers that were catching on fire in the 60s, and we have stopped directly releasing most pollutants into, most of those industrial pollutants into rivers, and so, in general, waterways in the United States are much cleaner than they were 50 years ago, much, much cleaner.
We have also expanded agriculture and expanded the use of synthetic fertilizers. And so there's also many more nutrients in our water bodies. And so we're starting to see more things like algal blooms because the algae are very happy. With all of those miniatures that are just sprawling like gangbusters because it turns out that you fertilize algae and they also grow the same way when you fertilize your farm, it grows.
And so we saw that in general, while we see a decline in the potential contributions of nature, in general, we were seeing an increase in quality of life, and it was a real nice fad in terms of the actual contributions of nature and the environmental conditions.
[00:30:40] Bridget Scanlon: Right. Well, I mean, you had several years in such a large group.
It must have been extremely interesting. And, after the fact, we often think, well, we knew all that anyway. But as you're going through it, you see that where you started off with your thinking was quite different than where you ended up. But others haven't gone through that pathway with you. And so they think, oh, well, and I get frustrated sometimes when that happens.
But it's interesting that you mentioned, the emphasis on potential contributions of nature versus the realized contributions. I mean, I was working recently on arsenic issues in drinking water quality and, and people, suggesting that socially vulnerable people were more exposed to groundwater.
Well, the issue is you have to first have the arsenic in the groundwater from the geology, and whether they're socially vulnerable or not, it's a sequence. And so just like you were saying, yes, you might have a wonderful riparian buffer strip and that would potentially reduce contaminants going into the streams but if you didn't have the farm fields up gradient, it was kind of irrelevant, but also what you described, I think, is the Clean Water Act where we have cleaned up, and considered the watershed and the land uses and the watershed and their potential to contribute contaminants to surface water mostly.
So that was, must have been a really nice exercise and a learning experience going through that and we benefit from the results. We see, you mentioned many different examples of nature based solutions and we see a lot of them around the world. I guess, one of the big ones would be the Amazon and you've worked in Brazil and the Andes, and maybe you can describe some of those examples.
And then, China has done many, some large programs where they have reforested areas to benefit water quality and things like that. Maybe you can describe some of those.
[00:32:43] Kate Brauman: Yeah, so one of the big issues that lots of people have started to notice and be very concerned about is erosion. And erosion that really comes from tilling the land surface, putting in roads, exposing soil directly to the elements.
And you do, you get a lot of erosion when you do that. And so, some of the nature based solutions that there's been a lot of focus on, in both China and Brazil, is thinking about, how do we stop that somehow? And this is water related, not just because the water carries the sediment, but because the water carries the sediment often into reservoirs. And those reservoirs were built for a reason. People want drinking water so they're storing it up so they can get it during the dry season. They want to be able to produce hydropower, so you need enough water in those reservoirs to get the pressure to run the turbines. And when you start filling them up with sediment, you have less capacity in a reservoir.
And over time, you can actually completely fill up a reservoir so that it's not usable at all. So there's been often some real focus on how do we manage landscapes to try to reduce the amount of silt and sediment getting into those reservoirs. So in Brazil, for example, the Brazilian forest code actually allows for paid people to plant trees up on ridges and on places where it's been identified that there is a revision happening to try to use the roots and the power of having big tree canopies to reduce the energy of rainfall to really try to control some of that erosion. In China, the program is sometimes in English called grain for green, where fields, actual farm fields that were being tilled and planted, have been replaced by orchards. And these are often, I think, usually production orchards, so it's not just a pretty tree, it's a tree that grows chestnuts or apples or something that you can harvest and eat and sell, but that you plant once and then you don't have to disturb the landscape again. And the idea again is to keep that continuous land cover so that there's a reduction in the amount of sediment so that downstream we see less of that sediment behind reservoirs and rivers.
[00:35:16] Bridget Scanlon: Right. So these are intentional management systems. And as you mentioned in Brazil, there's a payment for environmental services, PES, and they're paying the landowners to do this. And in China with a top down kind of political regime, they can effect these changes over large areas. And one of the things that you mention often then is the trade off that we need to consider when we promote different nature based solutions. And sometimes we're not aware of some of the potential unintended consequences that might come with some of these changes. I think one of the good examples was Rob Jackson, when he was at Duke, had a paper titled Trading Water for Carbon with biological carbon sequestration and growing tree plantations and its impact on water resources. And then I guess another example would be biofuels then trying to make green energy, but also considering its impact on water. Maybe you want to comment on those a little bit, the trade offs.
[00:36:19] Kate Brauman: Yeah, I think these are the kinds of trade offs that will become even more aware of both. And in good programs, we're thinking about those ahead of time. So in these reforestation programs, there's real questions about sort of, well, how extensive is this? Is this explicitly cited just in places where you're seeing a lot of erosion, but it's actually a relatively small fraction of the watershed.
So maybe you get a big impact on erosion, but a much smaller impact on evaporation. If this is not a place that is water scarce, if you're not really worried about how much water is available or small changes at the margin are not going to make a difference, then you have to worry about that. One of the things, though, that we've seen or not seen, I guess, is the sort of exciting but scary part is that most of these programs aren't really being monitored. They're being put into place without really robust measurement and monitoring schemes, so we often know what's happening on the landscape, if trees have been planted, and maybe, and where trees have been planted, because we can monitor that with satellites.
But we often don't have a good paired watershed or a long term measurement of the watershed where this is happening. And so we're kind of guessing about the hydrologic impact. We're running models, the models have physically based parameters. We developed those based on science, but we don't actually know if they're hyper relevant, especially in these tropical landscapes, with tropical weather patterns, with high topography.
So one of the things that I daydream about, it's like my great wish, when we do these, we should also put monitoring in! The rule of thumb, and this goes back a long time, for hydrologic impacts of large scale land use change is that you want to see about 20 percent of your landscape being changed before you see a hydrologic impact, and it's not hard to get 20 percent of your landscape changed from either grassland or forest to agriculture. When somebody wants to make a living by growing food, it's pretty unusual to see these nature-based solutions at that kind of scale. We just aren't seeing people reforesting 20% of a giant watershed, and so. We have to model. We don't really know right now what the large scale impact of that is, which is, I mean, the scientist in me is like, oh, this is so it's like, it's also a little frustrating thinking about management and making, really trying to make suggestions and recommendations for managers, other folks.
[00:39:15] Bridget Scanlon: And I think the changes that are being promoted through nature based solutions are kind of nice changes aesthetically oftentimes or things like that. And so we just take it this, okay, that's good enough. And we think it should do this and then assume that it's moving the water resource in the direction that we wanted.
And as you mentioned, growing a plantation for carbon sequestration in a wet area where water scarcity is not an issue may not be problematic. But considering, for example, Australia during the millennium drought, there was a lot of discussion earlier about tree plantations for carbon sequestration stuff. But during the latter parts of the millennium droughts, they forget it. And that would get into what Rob Jackson was saying, trading water for carbon, because you increase the evapotranspiration and then you're losing the water. And in these water scarce regions, that's a big issue. So I guess one of the benchmarks then to compare nature based solutions would be against traditional engineering solutions, levees or, or reservoirs or other ways of cleaning up the water.
Have you got any good examples of where you can directly compare these or it's difficult, it's apples to oranges.
[00:40:35] Kate Brauman: I think it is apples and oranges, but we need help. I cook with, I was going to say I cook with lemons and I eat oranges, but that's not what you said. You said apples and oranges, not lemons and oranges.
I cook with apples sometimes. The engineering solutions that we have built in the past were not built by accident. They were built at often great expense because things were happening in nature that we did not like, as in my house keeps getting flooded. If we built a levee between me and the river, I would get flooded less.
We have since come to understand both that these engineering solutions don't last forever, so we're going to have to keep investing in them, and that they are imperfect. And so, I think what there is now is... growing interest in thinking about green and gray infrastructure together. It's sometimes called nature based solutions with engineering solutions to kind of get the best of all worlds.
So maybe your house is still protected by a levee, but you recognize that your fields may be flooded. And there's some benefit to that. You get silt and nutrients that are actually good when they're deposited on fields. They're bad when they are deposited in your living room, but it might wipe out your crops for the year if that happens.
And so there need to be other kinds of flexibilities in the system. We also need this institutional flexibility that says, Oh, well, we'll pay your crop insurance because we recognize that because your land flooded, there were benefits downstream and we didn't have to pay disaster assistance to people whose homes were flooded.
And all of this is complicated. It's not just let nature be nature. It's how do we think about these systems together and kind of get the best part of what works while still protecting the things that are important to protect.
[00:42:45] Bridget Scanlon: I think we've come a long ways. Maybe early on, we just go in there and blast with some engineering approach.
And now we're becoming much more cognizant of the value of nature and preserving wetlands, restoring wetlands or things like that and recognizing their value. I think you mentioned the other day that nature based solutions oftentimes don't have many negative impacts, maybe from a biophysical standpoint. Maybe not many negative impacts, but also not huge rewards either.
So it's maybe a case of low risk, low reward, but it may not be the entire solution. So coupled with engineering solutions, then we might come up with the best approach to manage some of these floods and droughts or other environmental disasters or water resources, quantity versus quality and things like that.
So agroforestry, mixing and matching things and so that the people wouldn't lose their entire cropland, but they could mix and match with forests and things like that. So we're learning more and more about how to have hybrid systems where we can mix nature-based and engineering approaches to, to get the desired effects.
[00:43:57] Kate Brauman: Yeah, I think that's exactly right and actually in cities is one of the places where this is I think, easiest to see. I lived in Minneapolis before I moved to Alabama, and in one of the parks near my house, they had dug down one of the playing fields into quite a big pit. And then we put grass back in there, across the bottom and up the side, so it was sort of this fun rolling hill.
You often saw small children rolling down the hills, as well as still part of this open space and it collected water and infiltrated water when there was a really big rainstorm. And so this is obviously built, I mean, this was excavated to be as big as it was and as deep as it was, but it also allowed for this multiuse, which I think is one of the big benefits of nature based solutions.
And it was certainly a lot more pleasant than I'm hanging out in a culvert. Right.
[00:44:57] Bridget Scanlon: So, so we've kind of gone all over the map in terms of discussing nature based solutions. We defined some of the terms and natural capital and others and looked at some of the applications and the roles, the regulatory role and also the provision role for food, feed, fiber.
And then examples of where they've been applied and limited data and how effective they are because of limited monitoring and then how we can really try to combine them then with traditional engineering. So going forward then, Kate, do you think combining nature based and engineering approaches would be optimal then as we try to deal with increasing challenges with climate and other aspects?
[00:45:45] Kate Brauman: Absolutely. I think that's gotta be the key that we need to embrace the power of nature and acknowledge the power of nature. And also continue to manage it because we don't want to see people run over by floods and we do want to keep our houses safe and we do want our water to be clean. And so all of these really have to come together, but I feel really optimistic about it.
I think there's a lot of potential for sort of looking forward and valuable positive impacts.
[00:46:21] Bridget Scanlon:. Well, thank you so much, Kate. I really appreciate you taking the time today. Our guest today was Kate Brauman. She's the Deputy Director of the Global Water Security Center which is part of the University of Alabama. And she works for the Department of Defense, the intelligence community. I wish you the best in your work. And I admire all of what you've done in the past and all of the educational material you've made available in your papers and others. So thank you so much, Kate. Thank you,
[00:46:50] Kate Brauman: Bridget. This was a blast.
