Note: This transcript is auto generated and lightly edited.
AARON: Water isn't one of those things that unlike a vaccine, you can't take it and fix it and walk away. Water is something you have to do every single day. want that, we want to turn on our taps and we expect that water to flow every single day forever and ever. And making that happen turns out to be an amazingly complex process.
MONICA: Welcome to Policy for the Planet, a podcast exploring the global response to the climate crisis. We'll unravel the complex tradeoffs of different policy choices to steer us toward sustainable solutions and public well-being.
I'm Monica de Bolle, a senior fellow at the Peterson Institute for International Economics.
Welcome to the conversation.
Every creature in the world is reliant on water to survive, but four billion people — almost two thirds of the world's population — do not have access to enough water. The problem is getting worse. By 2030, 700 million people could be displaced for lack of water. Recurring droughts are not just affecting people's health. Water shortages are disrupting trade routes, hitting vulnerable resources like the Panama Canal.
Joining us to talk more about water scarcity's effects on the globe is Aaron Salzberg, a consultant providing science and policy advice to decisionmakers on issues related to water, climate change, and security.
From 2019 to 2025, Aaron served as the Director of the Water Institute at the University of North Carolina where he led the University's efforts to support better water management and conservation through research, policy, and practice.
Prior to UNC, he worked at the U.S. Department of State for more than twenty years – providing science and policy advice to five Secretaries of State on issues ranging from genetically modified organisms, to human cloning, to other issues related to sustainable development and environmental security.
So Aaron, welcome to Policy for the Planet. It's a pleasure to have you with us on the show. And I'm just going to start us off by asking you, as a scientist, a diplomat, an engineer, and policy expert, you have spent many years working to improve global water security. What does it mean to be water secure? And how did you get started working in this field?
AARON: Yeah, I think in the most simplest sense, being water secure means that people have the water they need, where they need it, when they need it, without living in fear of floods and droughts. so, and basically that falls down to just a couple of things. It's the quality, quantity, and availability of water. Quality, I think we all understand, is it too polluted for you to be able to use for the things that you want to use it for? Quantity, do you have enough for the things that you want to use it for? And availability or accessibility, which is, is it within reach? Is it something that you can actually access and you can afford it? And it's there when you need it.
And so if you've got water that's there when you need it and it's the right quality and the right amount, then you'd be considered water secure. If you don't, then that would be considered water insecurity.
MONICA: So talk to us a little bit about what the largest threats to water security are currently.
AARON: Yeah, we often think of it in three ways. Either there's too much water, too little water, or the water is too polluted for us to be able to use.
Many of these things I think we understand pretty easily. If you've got too much water in your town or your place of work is flooded, floods can create a huge amount of damage. They can disrupt economies. We've seen this many times throughout, certainly throughout Central and South America, but also in many places in Asia where a typhoon will come through or a hurricane will come through and it'll just devastate the economy. Lots of lives get lost. So floods can be really, really traumatic and devastating. That's one.
And we've seen that here in the US too. And in fact, it's a real challenge for us because a lot of our economic centers are along the coastline. And so they're particularly vulnerable to those types of effects. The other is that the water is too polluted. It's not in a condition that we can use it for the purposes that we want to. It may not be safe to drink. It may have contaminants, pathogens that make us sick. It may have chemical contaminants that also may cause long-term diseases.
It may be very pernicious things like lead, for example. know, a toxic metal that if it's in your water supply can impact neurological development of children, particularly when they're growing up. And that can really have long-term, lifelong impacts on people. And then the third is that we, another one that's pretty easy to understand, and that is we don't have enough. There's a drought. And so long-term, when long-term availability of water becomes limited, that can impact all sorts of things from our ability to grow food, our ability to have access to water to drink, as well as water for other uses that we might have within our own particular livelihoods.
MONICA: So to bring climate change into this conversation and you talked about, you know, pollution, you talked about droughts and I think, you know, most of us, when we think about water and climate change, we think about droughts. Right. Sometimes we think about floods, but I think the one thing that comes to mind right off the bat really is drought.
But how should we be thinking about this? How should we really think about water and climate change, the connections between the two and the implications thereof?
AARON: Yeah, you know, I think the most profound impacts of climate change will be on the hydrological cycle and how we get water and how water appears in the environments in which we live. And it probably will affect us in three main ways. You know, first is increasing temperatures. If it gets...too hot or if it gets hotter, people need more water to drink. Plants need more water to grow.
The increased temperatures have greater evaporation losses from lakes and reservoirs, so it's harder to store water where you might have it. So the first is that increasing temperature, which is really problematic in lot of ways, can also affect glaciers. We know in South America, but also in many places throughout Central America and other places in the world, a lot of the water is stored in the wintertime in snowpack or in ice.
And if the temperatures are rising and during the winter that precipitation falls as rain rather than as snow, then we don't build up that snowpack that we rely on in the spring when the temperatures warm up and that water begins to melt nice and gradually and it waters our crops. So increasing temperature can wreak havoc in lots of different ways and that's one key issue. The other is I think the changing pattern of precipitation.
And in general, I think we believe that wet areas are going to get wetter and dry areas are going to get drier. We're starting to see some evidence of that. And in particular, it looks like the dry areas are getting drier faster than the wet areas are getting wetter. But at the end of the day, I think we're looking at some places that had enough water to meet their needs may not have that water to meet their needs and other places are going to be dealing with more frequent floods.
And so the idea that the pattern of precipitation is going to start to change and that will impact where people live and how people live is going to be important. And then I think the third aspect is variability. And this is probably the tougher one to both understand but also to address. And that is, I think we're going to see an intensification of rainfall events and a compaction of rainfall events. In other words, rather than seeing rainfall spread out over a week, you might end up with a week's worth of rain in a day or a couple of hours where you get a deluge of 10 inches of rain.
And we're seeing this in many places. We've seen this here in the United States. We've seen this in many other places where we get these very intense compressed rainfall events. And what's likely to happen is we're going to see a greater time period between precipitation events. So those dry periods are going to become longer and those wet periods are going become more intense. The overall amount of rain that we get might be the same, but because of way it's now distributed, that creates a number of really interesting challenges.
If you've got a flood event, how do capture the water when it rains then so you actually have it for when the water's not falling? And so that becomes a water management issue and how you be able to respond to that becomes a real challenge for many places throughout the world. So I think those are three things, increasing temperatures, the changing patterns of precipitation, and of course the variability are the three things we think about in terms of how climate will impact water.
MONICA: How is it related to public health?
AARON: Yeah, it's really interesting. Of course, the obvious ways when water is polluted can impact human health either through pathogens or through chemical contaminants. But some of these things are really bizarre connections that we don't readily see and think about.
One example is Zika. You know, the mosquito only travels about a hundred meters. And what we found is that those mosquitoes were breeding in water jars that were occluded around the houses. Now, why are people keeping large vases of water around their houses? Well, they don't have 24/7 access to water. The water turns on sometime and turns off other times.
And so what they do is when the water turns on, they capture that water and they store it in these things around their house, which is an ideal breeding ground then for mosquitoes, which can then impact them in all sorts of different ways. There's other examples. One that I find particularly fascinating is the idea that we are all, many of us take antivirals and we pee those antivirals back out and they end up back in our water system.
And in fact, in most surface waters you can find are heavily loaded with some of these antivirals that we are all peeing back out. That's being taken up by some of the biota and the insects that live inside those streams and lakes. That's being eaten by bats. Bats turn out to be a huge reservoir for viruses. And if bats are being exposed to antivirals, all of a sudden they're developing viruses that are resistant to some of those antivirals.
We also know that climate change- That's fascinating path. That's right. And climate change as temperature goes up, that viral shedding from bats also goes up. So there's this linkage between climate, water, health that we might not have even thought of, just like there is between this energy linkage where, you know, if we're not providing energy in a regular way, then people are flood irrigating and they're using water inefficiently on their crops, or people are storing water around the household, which creates breeding grounds for vector.
MONICA: So it's really interesting set connections. It's a lot to think about. And they're all in and it's all fascinating but also kind of scary because the leaving I'm thinking back to my Brazilian roots and the fact what you described, you know, in terms of people leaving water around the house, that is a common experience. I have seen that and you're indeed right. I mean, it is a complete breeding ground. Right. And one we have to take care of, right? It's a major public health threat.
AARON: And this is something we have to be thinking about. this is what makes water so exciting, at least to me. I am not a water expert. I became a water expert in part because on any given day I could show up in the office and I could be working on a technical problem, a financial problem, a political problem, and it's a problem that mattered. Water isn't one of those things that unlike a vaccine, you can't take it and fix it and walk away. Water is something you have to do every single day. We want to turn on our taps and we expect that water to flow every single day forever and ever. And making that happen turns out to be an amazingly complex process.
MONICA: And I guess the variability aspect of it is really, really interesting because it touches on exactly as you said, water management and policies towards water management that many places will need to have in order to deal with these long dry periods and very short but intensely wet periods that of course affects crops and affects crop growing and is related to food security, which is an issue that we have brought on to this podcast, even though it's not the topic of this current episode that we're doing.
I do have a question though on this, on the issue of variability, when we start to think about recent examples of how that has played out, one of the things that comes to my mind is the Panama Canal and the fact that we've seen how these variable conditions in terms of rain cycles and hydrological cycles have affected the reservoirs, the principal lakes like Lake Gatun, which is principally responsible for supplying water to the Panama Canal. And not just that, it's the water supply for Panama, drinking water for Panama as a whole. Can you talk a bit about that specifically, not just the Panama Canal, but other examples of where we see the issues that you've spoken about playing out?
AARON: Yeah, what a wonderful and complex region, right? It's a very narrow strip of land, you know, compressed between two very big oceans.
And understanding even the weather patterns is really complicated in that area of the world. And you're right, even within the last 10 years, it was about 10 years ago that they experienced the three driest years on record within the region. And we've seen that pick up a little bit. We've seen a number of dry years over the last 30 or so years. We've seen an increase in storms in the region over the last 30 years. I think the real challenge though is we can't really disaggregate whether or not that's from normal weather patterns or it's actually the result of climate change.
What we do know is that these events are pretty closely associated with El Nino, which is a warming of the Pacific Ocean. And that generally results in drier periods within the canal. And that puts a lot of pressure on the canal. think if you end up with a, when that basin, I mean that basin, the watershed that supports the canal also supports about half the population of the country.
And so if you get, a real dry period, you have to make some really hard decisions about where does the water go. Does the water go to the canal, which is also a huge economic hub and generator and industry? It's also, we've got other countries who are very reliant. mean, about 6 % of the world's global trade goes through that canal. So if the canal is not functioning, you could have global impacts and something we have to really think about. So how do you balance then the canal versus the needs of the people who might be living in that basin and also suffering from water?
Shortages, right. How do they meet their own needs? And so there's a real demand, I think, to do some thoughtful planning for how you manage the needs of the canal and the needs of the people over the foreseeable future. And that's hard to do, especially when you don't know what that future looks like. How much water you're going to have, are going to have more, are you going to have less, are you going to be able to predict it and have good forecasts, or how's that going to work?
You know, I'll give credit to the…Panama Canal Authority, I think they've done a lot to both recognize that some of these issues around sustainability and climate change and the operations of the canal. think they've made a number of modifications recently to help reduce the amount of water that the canal uses. I think one of the major improvements was they now have these storage tanks that are alongside the actual canal. So instead of having the water go back out into the ocean, they cycle that water between those storage tanks and the locks and that allows them to conserve upwards of 60% of the water that's being used in the canal.
MONICA: That's really interesting.
AARON: It's a huge, huge benefit. There's also a lot of work to improve how people live in the region, how they're managing the land, making sure that we're not removing the forests and that we've got good vegetative cover, which helps keep that soil moisture into the ground and that they're better managing water resources at large within that entire basin. There may be a need in the future, depending on what happens, to actually augment those supplies by bringing water in from the outside. So maybe putting in another canal or a pipeline that brings water in from some of those lakes that are outside of the basin right now. But hopefully you'll be able to find ways to manage it and keep things within that. But yeah, there's no question the Panama Canal is a really interesting problem and really demonstrates how these local issues can be tied into the global economy. Exactly. Exactly.
MONICA: So, Aaron, I know that one other really interesting case that you've looked at is the Nile. What can you tell us about that and what's been going on there?
AARON: Yeah, this is a really interesting case where you've got an upstream country, Ethiopia in this case, who is looking to provide energy to a large portion of his population. Right now about 40% of his population doesn't have access to sustainable energy. You have a downstream country, Egypt, which is probably one of the most arid countries on the planet. And they are water insecure by almost any standard in metric. They are water insecure. And Ethiopia is now building a dam called the Grand Ethiopian Renaissance Dam. In fact, the dam is now already built, which can basically impound as much water as Egypt gets in a year.
So you could imagine the complications that might present to the downstream countries. And you've got Sudan stuck in between the two of them. And so how you've, and I do believe these countries could easily come to an agreement, let's say on, because it's a hydropower dam. Hydropower dams usually let the water go. Ethiopia wants to produce power. So that's great. They'll let the water go to produce power and Egypt and Sudan need the water to grow food and take care of other things. that under normal, that seems like it should all work out, right?
What happens if you get a drought? If you get a drought and the reservoir behind the dam now gets really low and now it starts to rain again, who gets first claim on that water? Do Egypt and Sudan get first claim because they need to feed their people and they haven't been able to grow crops in the last several years? Or does Ethiopia impound that water so it can fill up the dam and start generating power again? And that's where things get really complicated. That's fascinating. And how do you make those decisions then between the parties?
And again, this gets this idea that open communication, that regular assessing of what's happening in the future, what our current needs are, how do we manage this? That conversation has to be happening between all these countries, all.
MONICA: Switching to a different example, just because you have talked about it before and it's a region of the world that you also know really well, we have seen climate change and droughts affecting the Indus River, which originates in Tibet, but runs through India and Pakistan. And the escalation of tensions between those two countries, which happen to be nuclear powers, is escalating. So what can you tell us about that situation, which is also extremely interesting and ties into everything that we've been discussing.
AARON: Yeah, which we've even seen within, as this conflict has begun to grow over the last couple of weeks, that India is withdrawing from the water treaty that they have with Pakistan as retaliation for the inaction that they might be perceiving on the Pakistani's part and responding to some of these activities, the terrorist activities that were happening in the region.
And so water is actually being drawn into this broader geopolitical conflict. And I think that's something we are seeing more and more globally. I think water is certainly now being more recognized as a strategic, important, politically important, militarily important asset. And therefore it's becoming more more entwined in some of these broader conflicts that we're starting to see.
It's really rare, I think, that you'll see a conflict over water where an upstream country is using water in a way that a downstream country opposes and the downstream country goes to war with that upstream country to protect its access to water. That's certainly something we would, we're all, you know, it makes intuitive sense. know, as water resources become more scarce, we'd think that more competition would break out between countries in that way.
But what we find more often than not is that countries actually cooperate and work more closely during times of drought and scarcity to kind of solve those types of issues. It's also really hard to envision how you might win a water war. Because that water is upstream, what do you do? Do you invade that country and then occupy that territory so you can manage that water? Really, really tough. In the case of the Indus, a lot of really interesting characteristics here. One, it's a treaty from the 1960s. That treaty, by and large, there's a series of dispute resolutions that the countries have abided by.
And even when they've had major disputes over the water and particular projects and programs, if the countries themselves couldn't resolve it, they have two different mechanisms that they can use. They either go to the International Joint, sorry, the ICJ, the National Court of Justice, or they can select a neutral arbiter and they can resolve those issues. And when they've resolved them that way, they've actually abided by the decisions that were made. So the treaty has been amazingly resilient, you know, over the last 60, 70 years.
Part of the problem though is it really hasn't changed in the last 60 or 70 years. Right. And there's a lot of things that are changing in that basin. We're going to see this in many other regions of the world, but you the Indus is, it's fed in large part by glaciers in the Himalayas and the Karakum mountain ranges. And those glaciers, as temperatures rise, are going to melt. And that water is going to come rushing into the river system, which means maybe in the next 30, 40 years, we're actually going to see increased flows.
MONICA: That's an interesting point.
AARON: But once the glaciers are gone, then those flows are gone. There's a stock flow problem here. And so how do you build and design major infrastructure that costs billions of dollars to respond to one hydrologic environment that might exist for the next 30 years, but a different one that will exist 50 years out of that? And then how do you balance the needs of the countries during that process?
And so it begins to suggest how complex and complicated these things can be. There are good examples of how this can be done.
MONICA: Can you name one?
AARON: You know, one that really stands out to me is the Boundary Waters Commission that the United States and Mexico has. And in part because this is a treaty that dates back to 1944. I mean, they have a relationship on the border that actually predates that to the 1880s or something in that range. But the
This treaty that we negotiated 60, 70 years ago, we haven't modified the treaty either, right? Renegotiating a treaty is a very hard thing to do between powers. But what we have done is passed things called minutes, which are amendments to how we operationalize the treaty. And we have over 300 minutes. And so what's really been interesting is that this institution and the way that it works has really evolved over time.
And as new problems have come up, either with water quality or water availability, or the needs of the countries, or the changing dynamics between the countries, they've been able to sit down and talk about new ways of operationalizing that treaty, staying within the spirit and the agreement that they've got, but new ways of operationalizing it that meet the needs of the countries in a better way. I think if you're looking for ways forward to deal with a climate future, those adaptive and resilient institutions are actually the model that we want to follow.
I think you can imagine if we're two countries and we've got a river running between us and we can decide that you get 60 % of the river and I get 40 % of the river. And that might work for today to meet the needs that we've got. But over time, we're going to be changing who we are and what we're doing. We're moving away from being agrarian economies perhaps to more industrial economies.
And so, how we divide that water up really should be rethought. How we improve the technology that we're using to better manage water resources will also then change. Our population growth might not be the same. And so those percentages need to be continuously rethought. And so I would argue that institutions that can sit down on a regular basis, countries that can sit down at a regular basis, talk about the different, what the future looks like, given our best understanding of the science and the weather.
If this is going to be our future for the next five years, how do we then best manage this resource that we've got to meet our shared interests? And if we do that on a regular basis, I think not only are you solving your water problem and your climate problem, you're also strengthening relationships between the countries. And that dialogue process, that using science and evidence to inform policymaking can also be incredibly powerful in other areas outside of
MONICA: What I find interesting about this conversation is that you've highlighted throughout these examples that in spite of the fact that we hear a lot about how global cooperation is falling apart and how climate change is getting caught up in this and of course other issues, public health is getting caught up in this and so on and so forth, there are a lot of initiatives which continue to exist.
And in fact, as you pointed out, not only do they exist, they're very resilient and they're there, you know, even in an institutionalized way that actually allowed this cooperation to continue. So even if there is this sort of bleak picture on the horizon as it pertains to global cooperation at large, at least in some areas from what I gather, water management and these kinds of conversations between countries.
That is one area where things should be going fairly okay. Is that a fair assessment?
AARON: Yes and no. I do think water agreements have been amazingly resilient. And I think that countries are committed to working together on water, continue to work together on water, and they really try to make that work. I am worried about some of the things that we're seeing happen right now. I think the more authoritarianism
This movement towards greater authoritarianism, I think the decline of multilateralism is really beginning to impact the way countries engage with each other on these issues. I think the lack of confidence in science and in evidence can undermine the baseline data that we need to be able to make decisions. I think the growth of misinformation, because there are often parties that have interests that they want to advance through these types of conversations and they will seek to manipulate that data, that information.
I mean, in almost every transboundary base you go to, there's a mythology that's been developed and you have to break through that mythology. And ideally you'd want to use good science and evidence to do that. But now I'm even wondering how we do that. How do we engage people on a conversation even around science when people aren't sure? I think there's a...a lack of understanding about what science really is.
I think people often believe that, there are facts and we can ascertain a particular fact. And where science is the process about, it's evolving, right? It's evolving, exactly. It's a growth process. Exactly right. And your state of knowledge is improving over time as you learn more and more. And so it's imperfect. And so how do you manage these very difficult processes? How do you make decisions between governments? If you're a government or if I'm a government, well, here, I'll give you an example.
Let's say you and I are negotiating over a particular river and I ask you, how much water do you need? And you'll think about that for a second. The analog I often use to that is, okay, well, how much money do you need to retire? Right? Because, you might think, okay, I know how much I use every year and so I can multiply that by how many years I think I'm going to live and I can come up with a rough number. But then in the back of your head, you're going to start to say, what if my spouse gets sick? What if my kids go to college? And what if this happens? And what if that happens?
So maybe I better double that. And then because I'm responsible for an entire country and people, maybe I better multiply that by 10. And so all of a sudden that number begins to rise, right? And we don't even know, right? We don't know how much water is coming down the system. There's a lot of uncertainty. And so how do you bring science and politics together to address those issues around uncertainty around these social, cultural values, economic issues that are embedded within water to make those kinds of decisions.
And my own personal view is that the answer itself is not as important as the process you go through to get to that answer. It's really about how we learn to engage each other, that at the end of the day will allow us to work together to solve complex issues, whether it's water, climate change, COVID, whatever it is.
If we can ask each other hard questions, if we can sit down and look at science and evidence together and make good decisions based on that, and then we can recognize each other's interests and needs in a way that's honest, open, transparent, then I feel really good about our future and our ability to do things. When we start to move away from that, I get concerned.
MONICA: Well, Aaron, thank you so much for coming on the show. This has been such a rich conversation. I feel like I've learned so much from you. Hopefully we can have you back at some point.
AARON: Thank you very much. Anytime is my pleasure.
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Special thanks to Jennifer Owens and Alex Martin, our producers, Melina Kolb, our supervising producer, and Steve Weisman, our editorial adviser. This podcast is brought to you by the Peterson Institute for International Economics. Learn more at piie.com.
Until next time, here's to creating meaningful impact. Stay motivated, stay curious.
