How Can Regional Models Advance Climate Science?

Climate models have changed the way we view the world. While effective, these models are imperfect, and scientists are constantly looking at ways to improve their accuracy and predictability. MIT professor Elfatih Eltahir https://cee.mit.edu/people_individual/elfatih-eltahir/ has spent decades developing complex models https://eltahir.mit.edu/ to understand how climate change affects vulnerable regions like the Nile Basin and Singapore. In this episode of The Joy of Why, Eltahir tells co-host Steven Strogatz how growing up near the Nile in Sudan helped him realize that climate change doesn’t occur in isolation. To better understand climate-related impacts and to create more effective adaptation strategies, Eltahir says we need regional models that incorporate contextual data like disease spread and population growth. Eltahir also discusses his “Equation of the Future of Africa,” and he introduces the concept of “outdoor days,” which he hopes can improve public perception about climate change.

• 0:00Speaker 00

  Hi, I'm Terry Tao. My new book, Six Math Essentials, explores six concepts that have guided mathematicians like me throughout history. With a simple introduction to numbers, algebra, geometry, probability, analysis, and dynamics, I share how these ideas helped me think mathematically and can help everyone better understand our complex world. Mathematics isn't magic. It's a way of thinking anyone can learn. Please visit quantobooks.org to learn more.

• 0:31Speaker 01

  I'm Steve Strogatz.

• 0:32Speaker 02

  And I'm Janna Levin.

• 0:34Speaker 01

  And this is The Joy of Why, a podcast from Quantum Magazine exploring some of the biggest unanswered questions in math and science today.

• 0:45Speaker 01

  Hi, Jana.

• 0:45Speaker 02

  Hi, how are you?

• 0:47Speaker 01

  I'm good. How are you doing today?

• 0:49Speaker 02

  Yeah, good. We're back to it.

• 0:51Speaker 01

  We are, and our discussion is going to be about something I don't think we've ever talked about with each other, which is climate change.

• 0:58Speaker 02

  Yeah, I don't think we've had that conversation, surprisingly.

• 1:01Speaker 01

  Such an important topic in science and world politics and the future of our planet, you know, what our kids are going to be facing. We hear about it all the time, how all kinds of records are being broken in temperature, wildfires, droughts, sea level changes.

• 1:18Speaker 02

  Yeah, I live in a coastal city. I live on an island.

• 1:21Speaker 01

  Oh, yeah, I heard that.

• 1:25Speaker 01

  We're referring here to Manhattan, yes? It's true, though, right? But so I realize that I don't really know as much as I should about how the climate projections are being made. We hear all the time about climate models, but what goes into those models? And what is really the science of climate prediction? Also, what do we know about how things are changing around the world? And how are those changes affecting people?

• 1:51Speaker 02

  Yeah, I wonder a lot about how many models there are, if there are competitive models, but I think it almost surprises me how much they dovetail, how much they come together, but you know, how do they get their data sets? Very difficult problem, actually.

• 2:04Speaker 01

  Uh huh. Well, so I sat down with our guest, Elfa T. Eltahir, who is a hydrologist, a climatologist, a meteorologist at MIT. He taught me so much. I mean, really learned a lot. And Elfa T., he's originally from Sudan. And you know, that appreciation that he has from growing up along the Nile underscores the point that climate change does not just occur in isolation, has a very social and cultural dimension, that we really can't ignore, both in our analysis and response to this issue.

• 2:39Speaker 02

  Yeah, sure. We want to live on this planet.

• 2:41Speaker 01

  I think so. Anyway, on the science, we are going to hear from Elfa T. Eltahir, MIT professor. So let me pass it over to him. Are you ready?

• 2:52Speaker 02

  Yeah, I'm ready.

• 2:53Speaker 01

  All right, here we go.

• 2:57Speaker 01

  Welcome to the joy of why, Elfa T.

• 2:59Speaker 03

  Thank you.

• 3:00Speaker 01

  I'm really pleased to have a chance to talk with you. I noticed that you hold degrees in all kinds of different fields: civil engineering, hydrology, meteorology, hydroclimatology. First, could you just tell us, what is hydrology? I mean, I can guess what it is from the words, but how would you define it?

• 3:20Speaker 03

  Hydrology is the science of the water cycle. The way I think about it is the water cycle in its full extent, from rainfall to infiltration of water into the soil, into overland flow, river flow, then the evaporation into the atmosphere, and then the transfer of that water in the atmosphere from one region to another, until it drains somewhere else. Observing it, understanding it, predicting it, is the subject of the science of hydrology.

• 3:52Speaker 01

  So the movement of water through its cycle, from rainfall into the land, the plants, the atmosphere?

• 3:59Speaker 01

  Back again. Okay. And how about hydroclimatology?

• 4:03Speaker 03

  In a way, you could think about it as long term averages of the variability in the hydrologic cycle and how process heat that happen in the atmosphere, leading to formation and fall of precipitation, are connected to evaporation, soil moisture, and conditions over land.

• 4:23Speaker 01

  Now, one of the distinguishing things in your work is this attention to the social considerations along with the climate ones. How necessary do you think it is to take that multidisciplinary perspective, bringing both the social and the scientific together?

• 4:40Speaker 03

  Yes, very important. The way I describe it is bringing the context over which climate change is happening at regional and local scales. I tell my students that climate change doesn't happen in a vacuum, it happens in a context. When we emphasize heat waves in Asia, those are regions that are already experiencing lethal heat waves and people are suffering because of that. If you look at disease in Africa like malaria, too many children died from malaria in places like Niger and other corners of the continent. You look at phenomenon, for example, like water availability in the Nile, even without climate change, there is a conflict on water.

• 5:23Speaker 03

  There is too many people, too little water. There is already a system and there is stress. Understanding how climate change is going to impact society could not be developed subtly without understanding the context and the history. And so, carrying these climate studies at regional scale allows us to not only look at what the physical climate models are telling us, but to interpret those in a context where social processes and where society is already engaged in addressing complex and acute problems.

• 5:59Speaker 01

  So, we're going to spend quite a bit of time in our conversation about the Nile. And before we get into the science and engineering aspects of it, I understand that you have some personal connection to that part of the world.

• 6:13Speaker 03

  Yes, I was born like a few hundred meters away from the Nile in a city in Sudan called Omthoman. That's where I grew up. That's how I learned about the world early on. Seeing that huge amount of water flowing down to Egypt every year, the flooding of the Nile, the flooding season and the dry season. For a while, I thought the whole world would look like that. You know, you have a river flowing and then you have deserts. And I was more interested in the rivers than the desert.

• 6:46Speaker 01

  So for those of us who haven't been there, can you give us a little more description of the terrain?

• 6:52Speaker 03

  So Sudan is pretty much a desert region. The river flows from the south to the north across that desert and bringing huge amounts of water into Egypt. And the area right next to the river is utilized for agriculture for like thousands of years. So there is greenery, there is palm trees, there is agriculture. And that's basically how life in Sudan was shaped through centuries.

• 7:21Speaker 01

  Well, you've given us some indication already of how important the Nile is to Egypt, Sudan. It touches many other countries, doesn't it?

• 7:30Speaker 03

  Yeah, the Nile actually travels across 11 countries. There are two main tributaries of the Nile. The Blue Nile comes from the Ethiopian highlands. It comes with very strong flows and erodes very strongly into the Ethiopian highlands. And it brings a lot of sediment. So the color of the water itself will be darker. The White Nile, it travels long distances through South Sudan, through relatively flat landscape. And so the color is not as dark. They merge together in Khartoum, the capital of Sudan. And then they carry together as the Nile. And that travels until it discharges in the Mediterranean.

• 8:11Speaker 03

  In hydrology, the most important equation is the water balance equation. Other countries contribute to generation and to consumption of the water. But like 80% of the water is generated in Ethiopia. And eighty percent of the water roughly is consumed in Egypt.

• 8:29Speaker 01

  Once it became clear to you that you were interested in a life as a scientist, did you always think that you would come back to studying the Nile, having grown up, what you said, only a few hundred meters away from it?

• 8:40Speaker 03

  That's actually is a very interesting question that I wonder about myself. I found myself going back to study the Nile intensively, but I was just naturally drawn to look at that system and to study. It didn't happen by plan. I remember the first paper I had about the Nile was actually after I finished my PhD, people started learning about this phenomenon called the Al-Nilu phenomenon. Every few years you get a warming pattern in the Pacific Ocean, and it impacts weather and rainfall around the world, and mostly in the tropics.

• 9:20Speaker 03

  I got my hand in that data and I noticed that Al-Nilu seemed to correspond to years in which you have droughts in the Nile.

• 9:28Speaker 01

  Oh, really? Drought, huh?

• 9:30Speaker 03

  Yeah, that discovery did not happen through a computer or plotting a graph. It's just looking at the data. That took me to get the data, to do analysis, to do statistical significance testing and so on. And I published a paper in 1996 in which I argued that twenty-five to thirty percent of the interannual variability of the Nile is associated with this phenomenon, which is Al-Nilu Maniniya. When you have warming in the Pacific Ocean, you get drought in the Nile. And when you have cooling in the Pacific Ocean, you tend to have flooding in the Nile. The story of the seven years of flooding and the seven years of drought was mentioned in the Bible and in the Quran about, you know, a dream of that nature.

• 10:14Speaker 03

  And even if you don't believe in those religions, the natural variability of the Nile has been a subject of interest to civilizations for solving the fears.

• 10:23Speaker 01

  Wow, it's a really fascinating story. First of all, this timescale of seven years. Seems to be about right with what we think of for El Nino itself. Is that right?

• 10:35Speaker 03

  Yeah, it's around that. When you do spectral analysis, it peaks at that time scale. So you have the coherence between the two signals. The sea surface temperature in the Pacific Ocean, the river flow in the Nile are coherent at those time scales. But following that, there have been actually measurements of the water level in the Nile for almost a thousand years. I wrote a paper in which I described that as the longest record of a geophysical phenomenon. This is not like paleoclimatic records that you get from data, but people recording, measuring the level, and they were doing that for reasons that has to do with the taxation of the population. And so there is measurements from a device they call nilometer.

• 11:20Speaker 03

  I used in another paper that record to look at the occurrence of El Nino and La Nini in the past.

• 11:28Speaker 01

  On the face of it, it seems pretty unbelievable that something happening in the Pacific, I don't know how many thousands of miles that is from the Nile, but it must be close to halfway around the world or something. And yet somehow through what it's doing to what, the jet stream or something? It's affecting the weather in Africa?

• 11:46Speaker 03

  Mm hmm. A simple picture you could think about is for rainfall to occur anywhere, you have to have air going upward. So when you have different rainfall pattern over the Pacific, that enhances the upward motion in the Pacific and that air has to come somewhere else. And some of it comes over the Ethiopian plateau and inhibits rainfall over the Nile. That's a simple way of describing it. But it's quite interesting geophysical, what we call teleconnection.

• 12:17Speaker 01

  Teleconnection, I see.

• 12:19Speaker 03

  Yeah, they would call it a teleconnection when you have two phenomena that are so far apart having physical connection that explains some of the statistical association that you observe.

• 12:31Speaker 01

  Well, let's talk about now climate and its interplay with the Nile. And in particular, the use of regional climate models as opposed to global. So I wonder if you could walk us through why it's important to look at regional scales, what regional scales actually are in terms of distances, that kind of thing.

• 12:51Speaker 03

  Yeah, my focus in climate studies has been consciously at the regional scale.

• 12:57Speaker 03

  We need to understand climate phenomena at regional scales for two reasons. To be able to inform society about how climate change is going to impact them directly, but also to be able to inform how those climate change impacts are going to be distributed. People need to know the details of that so that they could design their adaptation strategies. I started looking at regional models during the period of my PhD work. And my PhD topic was about how deforestation in the Amazon would impact the regional climate of the Amazon itself.

• 13:39Speaker 03

  And so that was the first time in which I built a model of the regional climate around the Amazon. Because you are not focusing on the global scale, you focus on a regional scale. You can always have more detailed representation of the processes, more detailed representations of things like topography and coastlines and land cover. All are elements that are important in shaping the regional climate. And because of the high resolution, you could then connect directly to where people live. You could describe, for example, in a state like Massachusetts where I live, how conditions could be different in the eastern side of the state versus the western side of the state.

• 14:24Speaker 01

  Oh, really? That fine scale?

• 14:26Speaker 03

  Yeah, we could go down now to models that have resolution of about 10 to 20 kilometers, while the typical global climate model would have resolution in the order of 100 kilometers. The downside to that is you always need to have information to constrain the models at the boundaries. That's the price you pay. And we could get that information to constrain the boundaries, either from archived observations or we could get it from simulations that are performed with global climate models. The way I like to think about a regional climate model is like a numerical laboratory.

• 15:06Speaker 03

  That are set up for a certain region to study climate processes at that scale. And it allows to incorporate knowledge about details of the hydrology or the agriculture or the weather systems that have been gained and accumulated through time. We integrate that in our climate studies of that specific region.

• 15:30Speaker 01

  So let me just flesh out a few examples. You've already touched on some. You mentioned eastern and western Massachusetts. You mentioned the Amazon. That would be a much bigger region. There's the Nile River basin. Would that be considered a region?

• 15:44Speaker 03

  Yes, we run our model on the surface of the Nile, which is like the Isthupian Highlands, the Isthupian Plateau. The topography of that region is an important factor in generating the rainfall over the sources of the Nile. And if you try to simulate the formation of rainfall over the sources of the Nile using a global climate model, the resolution of the model would not be sufficient to represent the details of the topography that exist in reality. And so that's the kind of process that we try to incorporate and successfully do when we use regional climate models.

• 16:21Speaker 01

  I would like to ask one technical thing, being a mathematician and a modeler myself. For people who aren't used to what these models look like, can you just tell us in a little more detail? Like, are you solving systems of coupled, partial and ordinary differential equations for motion of air, for humidity, for temperature? I mean, what is it that you're actually doing? Is it all in the computer? Is there some other way, an analog of a wind tunnel or something? I mean, how do you do your studies?

• 16:52Speaker 03

  So, climate models are numerical models. They are numerical solutions of a set of partial differential equations, coupled partial differential equations. The way I describe them to my students is you could think of seven principles described with seven equations in seven variables. And the principles are conservation of water mass. Air mass, conservation of energy, conservation of momentum in three directions, and the state equation for air, the ideal gas law. So those are seven principles. You describe them with seven equations and you solve for seven variables, which are pressure, temperature, humidity,

• 17:36Speaker 03

  density, and wind in three directions. So you have seven equations, seven variables. You solve them on a sphere for the atmosphere. You solve a similar set of equations for the ocean. You couple them. When you come then to describe impacts on things like disease, agriculture, and others, you have to develop other models that are tailored to describe those phenomena in accurate ways. Always, you develop the models and you test them again in the past climate. So we have a lot of data for the last number of years, at least thirty or more years. And we test the models again in shows.

• 18:20Speaker 03

  We calibrate them for those conditions that had been observed before we use them to project the future. And this process is an ongoing process. We are always coming up, not just my group, but globally, scientists are coming up with better models. They are better representations, improving on their accuracy and they're reducing the uncertainty. And that's an ongoing process that happened in the past and will continue to happen in the future.

• 18:49Speaker 01

  I expect that you wouldn't just run one model at a time. You must have an ensemble.

• 18:54Speaker 03

  Absolutely.

• 18:54Speaker 01

  Because of parameter uncertainties, is that right?

• 18:57Speaker 03

  Absolutely. There are like forty centers around the world that are running models all the time. Each center has several models. And each model is run on different simulations. So an ensemble of realizations for the same phenomena. It's a very sophisticated modeling system that had been developed through the work of hundreds and thousands of scientists. It's a very interesting and very exciting experiment and experience that had been performed by the climate modeling community for all these years. Rooted in mathematics, in good mathematics and good physics.

• 19:37Speaker 02

  Well, I have a lot of questions. I mean, seven parameters actually doesn't sound like a lot.

• 19:42Speaker 01

  In saying seven, these are fields, right? It's a velocity field and a humidity field and a temperature field across the whole sphere. So space is in there and time. These are spatiotemporal fields, seven coupled partial differential equations, all in space and time. So you can look at the global scale. You often hear about global climate change. But one of the really special things about Al-Fati is he looks at a scale that is very regional and sometimes even local. Like, you know, what's the weather in Manhattan? Or what's the climate over Massachusetts or in Sudan or the Nile?

• 20:23Speaker 01

  And that's a really interesting math problem as well as important climate problem.

• 20:28Speaker 02

  Yeah, I was intrigued that he was saying, look, of course, our models get ever better. And there are all of these centers. We have lots of different ways of modeling to try to have some kind of resonance, some way of improving those results. But it's still such a tricky problem. It's just so complex. And you study chaos, so you know how delicate this is.

• 20:46Speaker 01

  Yeah, that's an interesting issue. He's very aware of chaos theory, as everyone is who studies both weather and climate. But we're going to hear more from Al-Fati Eltahir about climate change. So stick around and we'll be right back.

• 21:22Speaker 01

  Welcome back to The Joy of Why. We're here with MIT professor Al-Fati Eltahir, and we're discussing climate models and the changing climate itself.

• 21:34Speaker 01

  For people who haven't had a chance to visit the Ethiopian Highlands, I'm being one of them. It sounds like a beautiful part of the world. It's very green. It's a plateau. I mean, you tell us a little about it.

• 21:45Speaker 03

  And you describe it, Ethiopia versus the surrounding countries, which is Somalia and Sudan. Ethiopia is elevated. The temperature is significantly cooler. And the rainfall-producing mechanisms are much more efficient. If you think about it fundamentally from the Euphrates, deny water flow for all these southern affairs is because of the existence of that geological formation. It had also a lot of implications later on in our studies to impact of climate change and variability on things like crop production, but also things like disease transmission, mainly vector-borne diseases like malaria and dengue and so on.

• 22:30Speaker 03

  Again, a topic that I found myself teared towards studying and putting time on, mainly driven by my own experiences when I was living in that part of the world.

• 22:40Speaker 01

  Well, you mentioned your own experience. Did you yourself ever suffer from malaria or people in your family or friends?

• 22:48Speaker 03

  Actually, I have a story. When I was a student in the University of Khartoum in Sudan, I experienced many incidents of being infected with the malaria parasite. And I used to go, like, spend time in the university and then by the weekend I would really catch malaria. I go home. My sister is a doctor and I bring her the injections and she gives me the injections. So the first thing after I got my tenure at MIT, I had a friend of mine who was a professor at Harvard School of Public Health. I said, oh, can we collaborate on this? We do a lot of good stuff with very sophisticated climate hydrology modeling. Can we bring in that into the study of malaria? He introduced me to a colleague of his and we started working together.

• 23:33Speaker 03

  We collaborated as a team of hydrologists, entomologists and medical scientists and were able to develop very sophisticated models. Of how climate variability and climate change impact malaria transmission in African villages. And the thing about it is, it wasn't just modeling work. Because we extended collaborations with Harvard, with Spastan Institute. They have local institutions in Africa, in Niger in particular, where we were able to collect a lot of very detailed data in the environment of villages in Niger on things like rainfall and temperature, but also on mosquitoes, their numbers, different species of mosquitoes,

• 24:17Speaker 03

  but also data on prevalence of the parasite in the blood of children and so on. It's a very detailed model. I think one of the most sophisticated models of disease transmission. When COVID hit society years ago, I wished then that we had a model of the transmission of influenza or these viral diseases of the same level of sophistication. What we discovered is actually very, very interesting. Two is, a lot of the climate studies will come with these like negative projections. What we learned is that in Niger, climate change is not likely to worsen the situation. The situation is not good, but climate change is not going to make it worse.

• 25:00Speaker 03

  Which later on was not the case when we looked at the Iseupian Highlands. As the climate warms up, that opens the Iseupian Highlands for malaria, subjecting a population that has very little immunity to this disease.

• 25:16Speaker 01

  Is the work on the Nile and malaria a kind of case study in what the rest of the world can be expecting as far as impacts of climate change on disease transmission, on some social factors or whatever?

• 25:30Speaker 03

  That's an interesting question. So after I did my study on malaria, I had the opportunity to do research in Singapore. I shared with them that, you know, we have done this work on malaria in Africa. And it may have some relevance to a disease that's really a big problem in Singapore, which is Denguer. They were a little bit skeptical initially, but we finally actually made significant progress in understanding the environmental side of how Dengue is transmitted in Singapore. Singapore is a country with a very efficient public health system, very well funded, very well managed. But they're having a problem with Dengue.

• 26:12Speaker 03

  They have houses that have been visited by the public health specialists and they found evidence for the breeding of the Aedes mosquito, the mosquito that transmit Dengue. In the case of the malaria, it's the Anopheles mosquito, which is a different species. So, a graduate student of mine made a discovery that when the Singaporean authorities went very strongly against the Aedes mosquitoes breeding inside homes, the mosquitoes were smart enough to find the niche where they would breed outside the home, in small drains. And that's why their management of the problem had not been as efficient as it could have been otherwise. After a few years studying Dengue in Singapore, I came to

• 26:57Speaker 03

  the US and I was approached by the Department of Public Health in the State of Massachusetts. Because they have concerns about the mosquitoes that transmit Dengue are creeping into the state of Massachusetts. And my main advice to them was, the time to go after Dengue is not when Dengue flourishes and become a full-blown disease. When these mosquitoes are struggling to establish themselves, that the time you go after them vigorously so that you eliminate them. What we learned about Dengue in Singapore could help us develop strategies. Another aspect I could talk about is the regional climate of the American Midwest. If you look at the midwestern US and you look at the summer climate,

• 27:41Speaker 03

  you don't see warming of temperature as happened around the world, but you see actually cooling. And we attribute that to the changes in land use and land cover, the development of agriculture, more intensive agriculture, development of irrigation that happened during the 20th century, and increasing the rates of evaporation, the cooling process. Evaporative cooling is very efficient. And so as a result, we developed better understanding of the regional climate of the central United States, an understanding that should help us interpret the trends of global warming that are happening around the world.

• 28:20Speaker 01

  Well, those are great examples. And I think you're making the case pretty clearly that the lessons we learn from studying places like the Nile or Singapore are very relevant to things that may be happening closer to the US. Taking that as now established, let me just ask a little bit about some social factors as revealed in some of your studies. Things like population growth, increasing agricultural needs. Do you want to talk about some of that?

• 28:48Speaker 03

  Yeah, that's actually an important topic, I think. In a recent book, I coined a term describing an equation. I call it the equation of the future of Africa. It's a simple, actually, mathematic equation, which says the future economic growth is function of climate change plus technology adoption minus population growth. And I mean by technology here, things like fertilizers and better seeds and so on. So that's how we use water. And so those, I think, determine the future of Africa. Is how do we manage trends in climate, trends in technology adoption, and trends in population?

• 29:31Speaker 03

  I am a believer that population growth and controlled population growth is the number one threat of the future of the African continent. In Africa, the projections are roughly that the population of the continent, which is about a billion, is going to double by 2050. I'm not a demographer, but one thing I learned looking into the literature there is that demographic models are much more accurate than climate models. Because of a concept which we call the population momentum. So when you do analyses on water, on like agriculture, on many factors, you find that the impact of the growth in population

• 30:16Speaker 03

  is significantly larger than the impact due to climate change or any other process.

• 30:22Speaker 01

  Right, there's a lot of spin off effects of having large populations growing quickly.

• 30:27Speaker 03

  Exactly, but also think from the perspective of the African population, it's even more alarming the kind of suffering and the kind of disruptions in wars and famines that the existing population will have to go through in absence of better management of these trends. Climate is changing and population is changing rapidly. So I think that framework I described, where we have to control and manage those trends in addition to, of course, the role of technology. The role of technology, I didn't say much about it, is mainly agricultural technology and mainly technology that has proven elsewhere, like use of fertilizers, for example.

• 31:11Speaker 03

  I'm a strong supporter for the expansion of the use of fertilizers in agriculture in Africa. A lot of people look at fertilizer as a bad word, as like negative to the environment. It is a contributor to climate change, to water pollution. In other regions of the world, Africans have been using significantly less fertilizer than the rest of the world to the detriment of the productivity of agriculture. In addition to having a growth in population that's expanding rapidly, the African farmers have been working very hard, producing very little because technological advancements that had been developed and applied and used in Europe, in North America, in China and India.

• 31:57Speaker 03

  They did not find their way to really help the African farmer produce more efficiently. That technology is a proven way to improve productivity. And hopefully, that improved productivity taken with control of population, with management of the climate, could open a better future for the African continent.

• 32:15Speaker 01

  This question about differential use of fertilizers in the different parts of the world raises a kind of ethical question on a slightly different point, that so much of the pain of climate change is being born in Africa, even though they did not contribute very much to causing climate change.

• 32:35Speaker 03

  Yeah, when I think of the issue of climate, I think of three dimensions. There is where the emissions are coming from. Emissions, they did not come uniformly from around the world. In terms of impacts, the impacts are not impacting the world uniformly. And then the last thing is the ability of different communities around the world to adapt to climate change is not uniform too. There are societies in North America, in Europe, in Asia, that have the capacity to adapt to climate change. They have the institutions that could plan strategies to adapt to climate change, and there are resources. That does not exist uniformly around the world.

• 33:18Speaker 03

  And so, when I look at Africa, they did not contribute to the problem in the first place. The impacts of climate change on Africans are very severe, not uniformly. Like I gave the example of how malaria in Nigeria is not going to get worse. And then the capacity to adapt is not there. One recent concept that we developed in my group is a concept that we call outdoor days. An outdoor day is defined as a day like we have today in Boston. Like the maximum degree today is 18 degrees centigrade. And following this conversation with you, I am eager to go out and go for my daily walk. It's a nice day for a daily walk.

• 34:03Speaker 03

  This is what I call an outdoor day. And this is how we humans interact with the climate system. It's a resource. It's like when we have a nice day, we go out, we enjoy it. Our standard of living would be higher when we do that. Our culture would be richer when we are able to do that. And what we discovered in that study, unfortunately, that the impact of climate change on outdoor days is not uniform around the world. Countries in the tropics, mainly in Africa, and also some in South America and Asia, are going to suffer a reduction in outdoor days. Where we live here, where I live in Massachusetts,

• 34:45Speaker 03

  we're going to have more outdoor days in the spring and in the fall, maybe some in winter, and less outdoor days in the summer. In total, we get the same total back again, very small difference. But you go to places like in Bangladesh, or Sudan, or like Nigeria, and you see dramatic reduction in the number of outdoor days. That, I think, is a serious negative impact of climate change, and it's going to have implications, cultures are going to be impacted, and ways of living are going to be impacted, and standards of living are going to decline. The important lesson is that when we think of climate, the world is not flat. It has its like ups and downs.

• 35:30Speaker 03

  And so, exactly what you're saying earlier, there are ethical issues. There are issues of justice and so on that are deep, that society will have to deal with. I think our role in science is not really take sides in that sorting of different groups in society, but informing all of that. Because we provide numbers and quantifications of impacts that are neutral, but inform society to have the right dialogue about these important issues.

• 36:01Speaker 01

  I really appreciate your mentioning this concept of outdoor days. As someone who cares a lot about science communication myself, I think you've really done something.

• 36:13Speaker 01

  Extremely important with this new concept because so often the discussion about climate change, where we talk about global temperature going up by a certain date or something like that, or even the Antarctic ice, it's not that they're abstract, but it's a little bit hard to relate to them. Whereas when you say, "I'm not going to be able to go gardening as often," or "to ride my bike," or "play with my kids outside," people will really feel that. Or, in regions like, say, the Pacific Northwest, they may actually benefit in terms of number of nice outdoor days. As you say, the world is not flat. Some parts of the world will experience climate change as a net positive for them

• 36:56Speaker 01

  in terms of outdoor days. But still, anyway, the main point was, I think you've really made it very down-to-earth for people to understand what some of these effects will be.

• 37:06Speaker 03

  I appreciate your comment about that. I really think it's a significant ingredient to educate people about how climate change is going to impact them directly. One thing that we also did there, we developed a way we have it in our website so that the individual reader could participate in the analysis by selecting what do they regard as an outdoor day, what range of temperature do you like to have, and then we dig into the models and then we tell you, this is how that outdoor day numbers are going to change for you. I like that because it really brings the user into the analysis. Usually, we tell the public, this is how things are going to change and you should care about them.

• 37:50Speaker 03

  Now they are going to tell us, this is what we care about, and then we tell them, this is then how it's going to change if that's what you care about. You know, one thing I want to say about climate change, which is, we all know that there are lots of uncertainties about the projections of how the future is going to look like. There are uncertainties about that. And when people tell us, "Oh, our models are not accurate," yes, our models are not accurate because the history of science will not stop today. There are going to be people who are going to develop better models, they are going to have better studies. I mean, the future is open for the young generation of scientists to come in and become better than us, with better studies and better, more

• 38:30Speaker 03

  accurate projections. However, I tell people, the uncertainty we have goes both ways. The models may be... Over predicting, but the models could be also under predicting what's going to happen. And if anything, the more like we go through summer after summer and we see the news, I am inclined to think the latter. But the idea is not to dictate the debate, but to inform it. So that when people take positions about climate change and like, you know, is it real? Is it not real? Should we invest in mitigating it or not? They make those decisions and those discussions based on facts and the best of science rather than anything else.

• 39:13Speaker 01

  Well, let's close then with this question. You've talked about people making their own decisions based on having information. Would you say that's one of the main things that is motivating you to do the work you're doing to help the public here and in other parts of the world? Or is there something else? Like, what is it that motivates you to do the work that you're doing?

• 39:34Speaker 03

  I think two things. Informing society about how these changes that are happening, how they are going to impact things that they care about, water availability, extreme weather, diseases. Those are things that people care about. How are they going to change in their own communities? Not just like a global picture. That's why we use the regional model. That's one factor. The other increasingly is to help inform adaptation to climate change. That's also need to be built based on facts. And very briefly, this is my most recent engagement now. I am directing two programs, one in Morocco and one in Bangladesh.

• 40:16Speaker 03

  The one in Morocco is about water availability, coming up with solutions on how people could adapt to less water in the future. Climate projections are that not only Morocco, the whole area around the Mediterranean is going to have less water in the future because of climate change. So we are working on adaptation there. And then there is this project we have in southwest Bangladesh where they did not contribute to the problem in the first place. They are going to be impacted severely because heatwaves are going to be lethal. Cyclones are going to be lethal. And they don't have the capacity to adapt to those changes. And so we have a program there with collaboration with local collaborators to try and empower

• 41:01Speaker 03

  the local population with information and work with them to develop solutions that would help them adapt to that future climate. So that's the second part. One is inform mitigation. The other is inform adaptation.

• 41:16Speaker 01

  Well, El Fati, this has been extremely informative. You have come a long way since growing up a few hundred meters from the Nile. Thank you so much for sharing all your expertise with us.

• 41:30Speaker 03

  Thank you very much. I really enjoyed talking with you and I wish you all the best.

• 41:34Speaker 01

  Thank you very much for joining us on The Joy of Why.

• 41:42Speaker 02

  In these projections for the future, sometimes you can feel helpless. What are we going to do? Nothing can be done. It's all too late. But then he said something very interesting about adaptation. I mean, is he suggesting we're going to survive, but we're going to have to adapt?

• 41:58Speaker 01

  I mean, I don't think it's some kind of either or choice. I imagine that he would like us to be talking about what we could do to improve the current situation. But given the track record, yeah, I think we want to be on all fronts here. And that's what he's suggesting, yes.

• 42:17Speaker 02

  Mm hmm. Now, I like hearing about the climate science. It's such a social and politically charged conversation that I'm just curious how a person handles that in their scientific work.

• 42:28Speaker 01

  You know, we all need to be better informed about the science. And it is all too easy to just start lapsing into despair or talk about the political dimensions of it. I feel very strongly about the science communication part. There's a psychological dimension. If we're going to make any progress on either adaptation or mitigation or actually improving things, how are you going to get through to people? And people have tried many things, you know, but this idea of outdoor days, maybe that's a good way of piercing the bubble. I don't know.

• 43:02Speaker 02

  Well, yeah, asking people what they care about.

• 43:04Speaker 01

  Yeah, right, letting people say, not just top down, but get the people themselves.

• 43:08Speaker 02

  Tell us what you care about and we'll tell you.

• 43:10Speaker 01

  Right, you tell us your values, we'll tell you what's likely to happen. Also, very humble and realistic for him to say, of course, the models are inaccurate. That's the beginning of science, right? The next generation will improve it. That's always the case. There's just a lot to think about and maybe a lot to act on. It's sobering and yet exciting. I mean, there are a lot of opportunities to work in a very important area and really scientifically challenging area. All right, Jana, pleasure to be with you as always.

• 43:41Speaker 02

  Pleasure. Hopefully, we'll be able to hang out outside.

• 43:44Speaker 01

  Yes, let's have some outdoor days together.

• 43:51Speaker 02

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• 44:08Speaker 01

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• 44:54Speaker 01

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• 45:32Speaker 02

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