Lonnie Thompson

Zierler:

OK, this is David Zierler, Oral Historian for the American Institute of Physics. It is June 8, 2021. I am delighted to be here with Professor Lonnie G. Thompson. Lonnie, it's great to see you. Thank you so much for joining me.

Thompson:

Thank you for inviting me, David.

Zierler:

To start, would you please tell me your titles and institutional affiliations? And you'll notice I pluralize that because I know you have more than one.

Thompson:

Yes. I'm a Distinguished University Professor at Ohio State University in the School of Earth Sciences, and I have a senior research position in what's now called the Byrd Polar and Climate Research Center.

Zierler:

Now, what is the institutional affiliation between the Byrd Climate and Polar Research Center and the School of Earth Sciences?

Thompson:

Well, it's a long history. The Center's actually one of the oldest on campus. Initially, we were part of what was, at the beginning, the department of geological sciences. And the Center was the Institute of Polar Studies, and it was just on the first floor of the department. But with time, the interest in climate and cold regions grew, and the number of people grew. And so, in 1989, we moved to west campus, to our own building. We now have all of our labs on west campus, even though a lot of people here still affiliated with the department or the school are on main campus.

Zierler:

In terms of teaching and having graduate students, where do you consider your home department or most of your research to happen in?

Thompson:

Well, most of the research actually takes place in the Byrd Polar and Climate Research Center. I have students who come from all disciplines. What we do is certainly cross-disciplinary. We have students and post-docs who come from chemistry, physics, engineering, and I just finished teaching my graduate paleoclimatology class, and I had an equal distribution of students from the earth sciences, atmospheric sciences, and anthropology. You couldn't do it without input from all of these different fields. So to cover ice cores from remote parts of the world, you have to have lightweight portable equipment, drills, power systems, and then you have to have really talented laboratory people skilled in chemistry and physics to make the measurements. And then, of course, we kind of have a team that actually looks at all the different aspects of the things that we measure and try to put together a complete story for any of the particular parts of the world that we've recovered samples from. And then, ultimately, the big goal is to bring all of those together in a global picture of how the climate and the system has varied through time as recorded in ice.

Zierler:

Just for a snapshot in time circa June 2021, what are you currently working on, and more broadly in the field, what's compelling and interesting to you?

Thompson:

We continue to focus more on the low and middle latitudes of the planet because that area has been so neglected compared to the polar regions, where we actually started. I started my career comparing the very first records from Camp Century, the first core drill to the bedrock in Greenland with the Byrd Station ice core, which was the very first core drill through Antarctica. The Greenland core was drilled in 1966, and when they finished in the northern hemisphere, they took the drill to Antarctica. They drilled the Byrd Station core in 1968. So I started in the polar regions, but it became very clear there was no one looking anywhere else on the planet, and we needed to connect Antarctica with Greenland. And to do that, we wanted to look in between in order to have, truly, a global perspective. We've been very fortunate now to have drilled in 16 countries in addition to Antarctica and Greenland. I think we've been at this for about 44 years, and we have managed to have continuous funding with all the ups and downs that have occurred. But right now, the thing that we are really excited about is, we have an ice core record from far western Tibet, in the Western Kunlun Mountains. The ice cores come from about 6,700 feet, 22,000 feet above sea level. They come from a very high, cold, dry part of Tibet. They have a very long history preserved in the ice. Unlike Antarctica and Greenland, where you have melting at the base because those ice fields are so thick, three and a half kilometers, and you have geothermal heat coming up, this ice cap in far western Kunlun is only 310 meters deep, but it's frozen to the bed now and likely through time. And what we know about the physics of ice is, if a glacier is frozen to the bed, it can deform, and the layers can get very thin, but time cannot be removed. We have the first of two papers in review on these new ice core records. We are working on an hypothesis that these cores will be the oldest cores found outside of the polar regions. But it is possible for them to actually be much older. One of our big challenges is, how do you date very old ice? We have worked with ETH facility in Switzerland to measure things like chlorine-36 and beryllium-10. Chlorine-36 has a half-life of 300,000 years. What we know about chlorine-36 is that it's only produced in the stratosphere and through thermonuclear bomb tests at sea level. But in the natural world, it is only produced in the upper atmosphere. We know that the ice at the base of this glacier is chlorine-36 dead, so this ice should be over 600,000 years in age. Just how old is it? We're working on that question with some of our colleagues, like Michael Bender at Princeton, who does argon dating on the air trapped in the bubbles in the ice. The whole idea is that argon-40 in the atmosphere only comes from de-gassing of the magma and that gas has slowly risen through time. Our first approach is to look at some recent samples to make sure the ice is capturing argon-40 levels in the atmosphere today, and then to look at some sections in the bottom of the core, just to get an idea of what the argon-40 levels are there. Now, the problem is, these measurements require lots of ice, and an ice core is not that big. A core is about 11 centimeters in diameter, and we bring them up from inside the glacier in one-meter lengths. So there isn’t enough material to use these dating methods that we have unfortunately. And our colleagues who are working in Antarctica and Greenland face the same issues. If you find really old ice, which is something scientists around the world are trying to do in Antarctica, how do you know how old that ice is? This is a challenge no matter where on the planet the ice comes from. But this Tibetan ice core is unusual because it's not from the polar regions, it's from the mid latitudes where people live, and a place where we have tried to get the long-term history of climate and the environment. The other record we're working on is from Huascarán in Peru, which is the highest tropical mountain on earth. In 2019 we drilled two cores to bedrock in the col of the double-peaked mountain, and each of those cores is 168 meters. Then, we drilled two cores to bedrock on the South Peak at 22,200 feet. Since it's the highest tropical ice cap on earth, it's also the coldest. One of the tropical records that we're just now starting to develop is a history of methane. It's never before been successfully done on a tropical core. All of our methane histories are from the polar regions. And yet, here is an ice field right above the Amazon basin, the largest natural source of methane on the planet, and because these ice fields are so high in the atmosphere, and they're cold, they offer the potential of preservation of the methane through time. These records span 20,000 years, so they will allow us to look at the last 10,000 years, called the Holocene, when civilization developed on the planet. But we can also look at conditions right above the Amazon basin during the last glacial stage. So that record is fantastic in so many ways. We're working with a number of different universities right now to look at everything, including microorganisms preserved in the ice–and this is something we couldn't do until the last five or six years. The technology didn't exist to extract the DNA and determine how bacteria and viruses have changed through time. So to do that, we work with post-docs and scientists in microbiology departments. We're also looking at the pollen history to tell us how plants have changed, and we're hoping to get some indication of what happened to the Amazon Basin during the last glacial. There are two opposing theories about the ice age Amazon. One is that there were refugiums of vegetation in a largely savannah environment, and the other is that the rainforest has been stable through time. These two theories are behind why there's so much diversity of organisms in the Amazon rainforest. In refugiums, organisms were isolated, and so they evolved separately. Only during inter-glacials did the forest expand and combine. The theory of Amazon forest stability implies that over many tens of thousands of years common evolution took place. We're hoping to get some direct input to resolve this from measuring the dust, chemistry, methane, pollen, and microbes, so that we can actually add to this discussion from a record that sits right above the Amazon where the tropical easterlies flow after crossing the Amazon, before they’re forced up over the Andes Mountains. These ice core records are, to me, just incredible records, and I feel very fortunate at my age to still be very excited about what we're finding in the ice cores.

Zierler:

Before we go back and develop your personal narrative, I'd like to ask a few broad questions about the field that I think will punctuate our discussion. You mentioned briefly before about the role of theory in your work. In other words, your work is very much in the field, you operate in an observational and experimental mode. But I'm curious, for example, like in particle physics, advances occur because the theorists make predictions that are either borne out or not by experiments. In what ways in ice core science, climate change science, paleoclimatology does theory provide guidance for the work that you do?

Thompson:

Well, I think theory has always played a very important role. For example, the particle counters we use in the lab, called Coulter Counters, were developed based on the theory of how you determine the numbers and the volumes of particles. Those machines were originally developed to count blood cells. We adapted that technology to count and size particles in melted ice. As far as climate goes, there are all kinds of theories about how the system works, and to me it's very important to be able to support the theories, or rather the hypotheses, with the data. And yes, I'm very much a data person. I go with the data, what it says, and sometimes it agrees with the hypothesis, and sometimes it doesn't. And we have a lot of discussions now with the modeling community on understanding stable isotopes of oxygen and what drives them, particularly in the low latitudes. That’s been a controversy ever since I was a student. I had thought we'd be much further along by now on understanding the dynamics of what drives them, but it's a very complex system. My personal opinion is that we've been led astray in understanding isotopes in tropical precipitation. There is an international collection of precipitation samples from around the world. People collect rain at the surface in the tropics, then they measure the temperature and precipitation amount, like they do in the higher latitudes. They found that when it rains hard, the water is depleted in the heavier oxygen isotope, and the argument is that this is due to a precipitation “amount effect.” In the wet, or monsoon, season it rains very intensely. But because the clouds are convective, they extend very high into the atmosphere, sometimes over 70,000 feet. If you are drilling an ice field on top of the Andes, on Huascarán or Quelccaya, when you're in a thunderstorm you're in the cloud. And the cloud goes up much higher above you. So the actual condensation is taking place in a much colder environment higher in the atmosphere. If you're out in the jungle at sea level, and you're measuring precipitation, then yes, heavier oxygen isotopes will be depleted. But not just because it's raining harder, but because they are condensing two to three kilometers higher in the atmosphere in convective clouds. And so you should be measuring the temperatures up where the condensation is taking place in the clouds. That's what the isotopes are capturing, just like they capture temperature in the polar regions. But there's a lot of work to be done there. And until recently, there's been not so much data on which to actually base our understanding of what drives those isotopes. But again, I look at the records. When I look at the history from Huascarán, back into the late glacial stage, there’s an oxygen isotopic depletion there of about 5.4 parts per thousand, or per mille. And on Huascarán, in the last glacial it becomes dry, and yet the downward isotopic shift is 5.4 parts per mille. But if you look south of there to Bolivia, to an ice cap that we drilled called Sajama, and during the last glacial stage it was much wetter. Salt flats there like Salar de Uyuni, the largest salt flat on Earth, was a freshwater lake during the last glacial stage. The isotopic depletion of 5.4 parts per mille was the same as in the dryer zone, and the same as in Antarctica and Greenland. I find it very difficult to explain that based on precipitation because these areas had quite different precipitation histories. But to me, this is what the data says. What really happened in these remote parts of the world? Let's develop our theories from there. But you need both viewpoints and you also need people who don't agree. Because that's what drives science to find the truth. As I often say, in the course of my career some of my biggest critics have actually done more good for me than some of my great friends. [laugh] Because they're the ones who challenge you to say, "We need to know more here. Let's get some more data. Let's see if we can really understand this." So I think this is just part of the science that we do.

Zierler:

As you well know, the field of climate change science is impossibly complex, requiring a range of expertise across sciences and beyond. Very broadly, what does the ice core record contribute to our overall understanding of climate change?

Thompson:

Well, I've been at this for 44 years, but it is actually my opinion and that of a lot of other people, that ice is probably our best recorder of the climate history on this planet. And the reason is that it records not just climate, things like precipitation and temperature, but it also records the drivers of climate like volcanic eruptions. And we know those impact climate on short terms. Ice also records things like greenhouse gases in bubbles. So, we can measure how carbon dioxide, and methane, and nitrous oxide varied through time. Variations in the output of the sun and how that has varied through time are determined by cosmogenic nuclides that are archived in ice cores. We know those are the variables that drive those temperatures and precipitation climate records of the plant. You can see both climate drivers and indicators in the same ice archive and look at those relationships, and how they hold, and how they vary as you go back through time. So to me, these are critical records. But the other part is that glaciers are not just recorders of that history, they are responders to, and in some cases, drivers of changes in the climate system. But unfortunately, when I started my career climate change was not an issue. I went to the tropics to understand how I could connect the records of things going on in the tropics like monsoon variability and El Niño/Southern Oscillation to polar records that we started analyzing. We went back year after year to glaciers like the Quelccaya Ice Cap, the very first tropical ice cap ever drilled. We drilled it to bedrock in 1983 using solar power, which at the time not even the National Science Foundation thought would work. But it turned out to be a wonderful source of power at 20,000 feet in the tropics. Even in 1983, the panels performed 20 to 30% above manufacturer specs. And of course, you don't pollute the environment that you're trying to study. So there are all kinds of feedbacks that come from using that type of power source. But to me, the key is trying to understand the detailed histories. Often these records have annual resolution, so you can really look at what happened in 1789 in the Andes of Peru, in the Himalayas, in Africa, Greenland, and Antarctica. So you get this really detailed history of not just climate, but the drivers of climate and how those are recorded differently in different parts of the world- what's similar and what's different, what's local, what's regional, what's global. You just have to have a global array of records in order to do that. That's pretty much what I've spent my career trying to collect. We keep ice core archives in the freezers here at Ohio State, stored at -30 degrees C. We have post-docs who are now going back to that archive to study things like ancient bacteria and viruses. Some of those cores come from glaciers that no longer exist in the natural world. We go back to those sites, observing and documenting the loss of ice, and seeing glaciers that we had drilled 20 years earlier actually disappearing. That really got me very concerned about what was happening in these very remote parts of our planet.

Zierler:

On the other end of this, the science of climate change demands a global response to what the ice record tells us. This response, of course, is incredibly fraught, and it exists on a range all the way from complete denialism that global warming is anthropomorphic, all the way to radical calls for ending the use of fossil fuels tomorrow and reorienting our society. In your 44 years in the field, in terms of all that you've learned, where are you on that spectrum in terms of the urgency of the moment?

Thompson:

That's a good question, a difficult question. I think this is one of the biggest challenges we face in the 21st century. And we will have to deal with it. It's not an option not to deal with it. I testified before the US Senate on this issue. But after seeing the lack of any progress as far as getting us off the trend that we're on, I started going to some behavior analyst meetings to talk with people who study us and why we do anything. The climate is complex, but we are really complex. And you try to understand, "How do you motivate millions, billions of people to do what's in their own best interest?" When you look at that, you start understanding some of our characteristics that I think work against us. When it comes to climate change, we're concerned about millions of people being displaced in Bangladesh by sea level rise, but we're more concerned when our own house goes underwater. It's just human nature. But I would also say that when it comes to climate change, it's no longer something happening in some distant part of the planet. It's happening almost weekly here in the US as well as in countries around the world. To me, it's probably that observation, that humans everywhere are actually experiencing what can happen when climate changes radically. People who spend their lives trying to work, save money, get a house, raise their family, and then to realize all of that can be lost in a few seconds from an extreme event, and the costs of those extreme events are rising exponentially. If you're in the insurance business, you know this. All the models that are used for risk assessment in the past don't work for risk assessment in the future, for example the number of wildfires. I'm always amazed when I look at how things have changed since the first time that I testified before the US Senate on climate change in 1992. This was after I observed, for the first time, melting at the summit of the Quelccaya Ice Cap, which I started studying in 1974 when I was a graduate student. To see melting on what was the largest tropical ice cap on the planet, was worrying. But I was very optimistic in the 1990s that, in our country and around the world, people were actually working together. Different agencies were working together. And I thought we were really going to make some progress. Unfortunately, that didn't pan out. In fact, I would say that if you look at the trend of carbon dioxide in the atmosphere, it's not only rising, it's accelerating ever since Charles Keeling started making those measurements. And it doesn't matter that we have all of these intergovernmental panels on climate change. We have reports—the first one came out in 1990 and every five to seven years, there's a new one. It's an assessment of our best understanding of climate science for the globe. Despite them, CO2 continues to rise and accelerate. No impact. Even during the pandemic, carbon dioxide in the atmosphere rose 2.24 parts per million. Even when there are economic shutdowns and all these other things, it's still rising. And you can only imagine what it'll look like in 2021, with everything coming back online. So to me, the big challenge is trying to understand us and what motivates us. But I am absolutely convinced we will deal with this issue because we won't have any choice. It's just amazing to watch. I'm based here in Columbus, Ohio. I always have believed that there would not be an issue with climate change and understanding it if there was a glacier now in Ohio. Because you would see it changing every year, just like I have had the privilege to see on so many glaciers in so many remote parts of this planet during my career. And some of these, we go back to every two or three years, whether we're funded or not, just to document that change that's taking place. Because it's sad, but the day will come when our children will not see these snowcapped mountain ranges. These glaciers are going to disappear. I would like to think that we could prevent this. But if you look at the fact that we have a lag in our climate system of 25 to 30 years between the elements in the system such as carbon dioxide that are in place now and before we see the full response in the glaciers, the ocean temperatures, and the like–and unfortunately, these small mountain glaciers don't have that kind of time. They will largely disappear, and along with them, the history they contain about our past. And even if we're lucky and can turn this around, and the temperatures of the planet come down, and the glaciers start to grow again, they'll be recording a new history. The old history will be gone. So, as I've moved through my career, I have seen our activities change more to a salvage mission. Get those records that are critical, get them into a freezer, extract as much information as you can now, knowing that 20 to 30 years from now, science will continue to advance, and our ability to extract information will continue to grow. But those natural archives, the ice, will be gone. That's what drove our drilling of Huascarán in 2019. This is the highest, coldest tropical mountain on earth, and we had taken some shallow cores up there in 2016, and we knew the record was still being preserved. We led the expedition in there to recover those in 2019. But these things aren't easy. We have to move six tons of equipment into these countries. We had to have the permits and the working connections. It's not like Antarctica or Greenland, where you've got some big arm of the US government flying you down. You've got to go down, you've got to find the right people, you've got to get the right mountaineering teams to get that equipment up to the tops of these mountains, and then you've got to get that ice out of there and keep it frozen, or all's for naught. And it's the tropics. Yeah, it's a polar region on top of that mountain, but down at the base, there are palm trees. And you've got to be able to move and keep that core frozen. And then, you've got to deal with local uprisings because often, in these areas, it doesn't matter whether you're in the Andes of Peru, the mountains of New Guinea, or the Himalayas, the glaciers are sacred places to some of the indigenous people. This is where their gods live, this is where the spirits of their ancestors live. You're coming there to drill often into what they consider the skull of their God. In Indonesia, they actually accused us of stealing their memories. I told them, "That's exactly what we're doing, stealing those memories. Because the day will come when your God's head will be gone. And the only memories of your God will be in a freezer at Ohio State University." We drilled there in 2010. But we monitor that glacier, and in the next two or three years, it will disappear, be totally gone, and the only history from that ice is here in a freezer. So to me, this is kind of a salvage mission. Every project we're on, we've never had any big funding. They are three-year National Science Foundation-funded projects. Each one of ours competes with all the other projects that they have to fund each year. But we had a mission from the beginning and a map of where in the world I thought we would likely find quality records. And we have just systematically gone around the globe. The other part about our mission is, there are times when you can get into certain parts of the world, and there are times when you cannot. For example, our team was the first to go look at glaciers in China when relations were first normalized with the Chinese. We were also the very first to go into the Soviet Union, just before it collapsed. This is because we had made contacts–and to me, the world is about people, and making contacts with the right people. The beauty of science is that we're not limited by borders. The things we study cross boundaries, we have to avoid the nationalism and all the other things that tend to divide the world. But we were actually able to get into Franz Josef Land in the Russian Arctic between the time that the Soviet Union fell and before the current Russian government got established. There were three years when we could go up there. I actually was on one of their nuclear ships. The captain took me down below, showed me the reactor, let me film, because he thought that their government would become like a democracy and that they would have companies. He was looking to create clientele for the use of this ship. I got to go to drill on Graham Bell Island, which is in the Franz Josef Land islands. And there, we actually landed on one of these air strips that were put in during the Soviet Union to bomb the US over the north pole. They'd never been opened to any foreigners. But in this three-year period, we got in, we drilled, got the ice core out of there, and the place shut back down. It's not been opened since, and it wasn't opened 30 years before. We've also been very fortunate to work in Tibet. We have an array of ice cores from glaciers across Tibet. They're the only ice cores in storage in the western hemisphere from that part of the world. And given politics and the way the world works, you never know when that will no longer be accessible. When I look at the world, there are windows, and they open sometimes, and you can jump through and get that record, get it out of that part of the world, but you have to realize they also close and you lose that opportunity. But I would say probably, the thing that I have learned most about human beings and the thing that I'm optimistic about regarding the future and our ability to work together on climate change issues is, our projects are international. When we drill in the western Kunluns, we have Russians, Chinese, Tibetans, South Americans that work on that team. It may be 60 people on a team to do a project like that. And here you are in this very high, very remote, very cold environment. You're at the end of the food chain. There's not very much oxygen in the air at those elevations. And yet, that team can work together with a focused goal and reach the objective of drilling those ice cores to bedrock and getting them out of those parts of the world. So I think that despite our differences in cultures and beliefs, when we face a common cause, a common objective, and we can focus on that objective, then we can work together to solve that problem. And you're absolutely right, when it comes to climate change, it's very complex because it brings together political systems that have different value systems, but it also brings together a danger that affects all of those systems. And I think that it may, in the end, be one of those things that actually makes all of us realize that we're only human beings. We're on a planet that has limited resources. And we need to protect those resources for the future. If we've learned anything from our international space programs, it's how unique our planet is for life as we know it. One of the things I truly appreciate about what I do is, I get to see and work in areas sometimes that no other westerner has ever been and meet the people who live in those areas. I'm always amazed at how generous these people are and how they work with us so we can accomplish our goals. So I continue to be optimistic, but I'm also a realist, that unfortunately, I think we're going to have to suffer quite a bit before we actually get all on the same page to deal with this issue.

Zierler:

With all of your efforts to convey the science to the broader public, what have you found to be the single most compelling point to counter this pernicious idea that climate fluctuations are natural, and that the planet has always been through colder or hotter spells in the planet’s history?

Thompson:

Well, there are two parts to that. One is, I've always found the history, photographs of glaciers through time, as being very effective. I can talk, and I have, about isotopes in the US Senate and with Congressmen, and you might as well forget it. Their eyes just kind of glaze over. But if you show them pictures of the change, they kind of grasp that. And moreover, it's very clear that a glacier has no political agenda. It doesn't really care about us or what country it's in. It's just responding, summing up all the things that are changing in its environment. It's kind of an unbiased view. The other point I always make is, yes, the climate of this planet has changed. As a geologist, I know there have been times when there were no glaciers on this planet, and sea level was 120 meters higher. The difference is, we have never had 7.8 billion people living on the planet. We settled this earth on sailing ships and so, we have all this infrastructure that we've built at sea level. We have navies that have all of their infrastructure at sea level. Their ship productions, their fuel supplies, their strategic bases out in the Pacific Ocean. And suddenly, all of those are at risk as these glaciers and ice sheets melt. In the past, back 60 million years ago, animals, as the sea level rose, migrated inward. And when it fell, they migrated back out. Well, we're going to have to do the same thing. Only, we're going to lose a lot because we've built and invested all of this infrastructure in these coastal areas and that's going to cost. I don't see any way around that. The problem is the little mountain glaciers respond faster. They're closer to the melting point, they're smaller. They respond slower. But these big ice sheets are now starting to respond, the margins around Greenland and around Antarctica. We have many meters of sea level rise tied up in those big ice sheets and sea level's going to rise. You can look at a place like Miami. High tide, streets get flooded now. You're not going to be able to build walls there like you did in the Netherlands to keep the sea out because underneath Florida is calcium carbonate, it's limestone. It's full of holes. You build a wall, the water's going to come under, come up on the other side. And so, we're going to lose large areas where people now live. Of course, that means we're going to have huge migrations of people coming from not only the coastal areas and lowlands in the US, but they're going to be coming from parts of the world where people don't have any options. If you're in Bangladesh, you're going to move. The sea level rises, you don't have any choice. You're going to take your family and move. And the question is, of course, where do they go? If we've learned anything about immigration and migration, this is a real problem. It doesn't matter what country you're in. When people get displaced in one part of the world, they move. How do you deal with that? And again, this is an international problem. These changes are so big. It's not something that the US can solve on its own. And it's not something that China can solve on its own. Or India. These are things that we have to find solutions to and work together to make that happen. One of the things that we have tried to do is to promote, in science, the exchange of people from different countries. We have what we call a Third Pole Environment program involving different countries. This is the way scientists work. I think it was 2009, I met with a German scientist who worked on ecology in Tibet, Volker Musburger [?], and with Yao Tandong, who is now in the National Academy of Sciences in China, who I knew when he was a graduate student. We met in Chicago. We knew that there were a lot of different studies in Tibet, but nothing was integrated, nothing was standardized as far as measuring accumulation on a glacier. So we launched what we called the Third Pole Environment program. We had a number of workshops in different countries, and we would bring scientists from not only China and the US, but any scientist who had an interest and was working in Tibet. More importantly, we'd bring together scientists from Nepal, India, Pakistan, and the countries that depend on water coming from those glaciers up in the Himalayas. When we started that, it was very difficult to get visas for, say, a scientist in India to go to a workshop in China. And likewise, to get a Chinese scientist invited to a workshop in India. But the first part of developing an understanding of each other is through establishing communication and science is a very good way to do that because we don't make things, we don't sell things, we have no military objective, but we get people talking to each other. And people start understanding that yeah, we have different cultures, but when it comes down to it, people are interested in their careers, their families, their survival. These are common in all cultures. And I think the best way to establish this understanding is to build these long-term relationships. I'm really proud of the fact that when we drilled Huascarán in 2019, one of the individuals that was on that project I had met in the Soviet Union back in 1990. Since, he's worked with me all over the world and he's worked with my Chinese colleagues. And we have a new, younger generation coming along, and they're now joining us on these expeditions. But the whole thing is just to build an understanding that, in fact, we're all human beings, we live on a planet, and we're facing a very serious crisis. It's still, to me, a question of whether humanity will actually come together and deal with this. Because when I look toward the future, there are two possibilities. You can become very nationalistic, build walls, try to protect your resources that you think you and your people need. Or the alternative is, you start building bridges, where you strive to understand and work together for a common solution to a problem that will impact us all. To me, that is the only path forward that ensures that there will be a future that we can all live with. So, the climate crisis might be that one thing that, for the first time in the history of humanity, we actually come together to work on.

Zierler:

I hope so.

Thompson:

I hope so, too. And like I say, I'm optimistic, just based on what I've observed. But scientists are different than some other groups in our society in the way we view things. But I believe that there are things that tie us closer together than those things that divide us. That's where the hope exists. I also see the hope in the younger generation of students and faculty who are coming along. Because many of those are interested in science, but they're also very interested in making a difference in their futures. I think this is a very positive sign. Before the pandemic, young people were taking to the streets around the world to protest the lack of action of their governments on the issue of climate change. And to me, this is a good sign because they're voicing their concerns about their futures. I think this is exactly what has to happen in order to get these systems to actually change, to make the changes that are required. But I also believe that we have to work together. I grew up in West Virginia. I actually came to Ohio State to study coal geology because I was looking for a job. I got this offer to look at ice in what was the Institute of Polar Studies. My first thought was, "How could you ever make a living looking at ice? It covers 10% of the planet, and it's in places where people don't live. How would you ever have a future looking at ice?" But when I took my first trip to Antarctica as a master's student, I couldn't believe it. Here's a continent bigger than the US and Mexico combined, 98% covered with ice, that there was so much ice on this planet. Most people don't think about that. But it's truly amazing, and it's truly amazing how much sea level is tied up in those massive ice sheets. But I would say that in those early days when I started, climate change was not an issue. No one was talking about global warming. My interest was only in the glaciers, how glaciers behave in the tropics versus in the polar regions. But it was doing this and going back to these same places through time where it became very clear that we face a really big issue here. When you see this on so many continents occurring, and the message is the same, and it doesn't matter whether you're looking at the message that's in the ice through the parameters of the measurements in the ice or looking at the glaciers themselves. They're all indicating that the world is warming, and the ice is melting. So it becomes a very clear, simple message that requires that we all do what we can to make a difference for the future.

Zierler:

Well, let's go back to West Virginia. Let's start, first, with your parents. Tell me about them.

Thompson:

Well, I feel very fortunate to have had two parents who loved the family, the kids, even though we were very poor. My mom and dad both had eighth grade educations. It wasn't because they weren't smart, it was the lack of opportunities in those early days. My mom loved school, but her father had cancer. And she had to stay home and take care of him. Toward the end, she could just pick him up, take him to his chair before the window. But she didn't get the opportunity to go to school. My dad was an electrician by training. He was in the military in World War II and was military police. But he had a heart issue. And because of the heart issue, it was difficult for him to get jobs at companies like Westinghouse and some of the big companies because of medical issues. So he ended up doing a lot of really difficult jobs, where those standards weren't required. But my mom, I have to say, is the one who stressed from day one, as early as I can remember, the importance of an education. And I was very fortunate that in 6th grade, I had a science teacher, Mr. Underwood, who was very much into weather, calculations of dew points, and such. And so, I really got involved in that. At one stage, when I was in high school, I actually had a weather station in our barn on the small farm where we lived. I'd do recordings in the morning and evening, I'd get the national weather maps. At that time, you could actually get a daily weather map sent from NOAA and see what was happening across the country. I got the idea that these systems form, and they move across. I started forecasting weather for the local community, and I'd get my lunch money at school by betting a student it would rain the next day and being right. More right than wrong, I should say. But it was a struggle, growing up. I had four jobs when I was in high school. My dad passed away when I was a senior in high school. And that was very difficult for my mom because back in that period, it was common that the man was the head of the house and the breadwinner and the mom took care of the kids. But suddenly, here's my mom with three kids, and she'd never been allowed to work. So, it was a big change for her. But she adapted, and she even got her high school diploma. But all three of the children went to college. And we did that through scholarships and the like. But unfortunately, my sister drowned in an automobile accident at 19 on her way to college. She caught a ride with a friend to get back to college. But I would say that the impact of both of those events taught us that if you're going to do something in life, you'd better get on with it because there's no guarantee how much time you're going to have. And so, I think that those events in life early on can either break you or they can force you to focus. I think in my case, it forced me to focus. But from the time I was I high school, I was interested in science. I'd always been interested in science. And actually, when I went to Marshall University, I enrolled in physics. But I spent my first two years actually catching up. Having grown up in this rural community and high school, we didn't get all the exposure that you really needed in chemistry, physics, and the like. So, I spent the first couple years really catching up. I was in physics for about three years before I took a night class in geology, which dealt with big things, things that were outside. And I thought, "In physics, I'm going to end up in front of a computer somewhere, and I want to be outside." And so, I switched when I was junior to geology. I thought, "What am I going to do after I get my degree? Well, I've got to get a degree where I can get a job." And so, I did my undergraduate at Marshall, graduated, came to Ohio State in 1971.

Zierler:

Why Ohio State? Was there a program there that was particularly strong?

Thompson:

Well, at Marshall, the chair of the department had gotten his PhD from the University of Chicago and so he was really good at understanding geology and the practical side of it, how you could take minerals and turn them into industrial products, things like that. But there was another more recent, younger faculty member, Dick Bonnett, who had gotten his PhD at Ohio State. I think it was when I was a junior, he had a colleague who was from West Virginia but worked as the state geologist in South Dakota. I got a summer internship in South Dakota as an assistant state geologist, I and spent the summer sampling well water across the state and mapping moraines left by the glaciers in that part of the world from the last ice age. And so, I got interested in that. When I applied to graduate school, Dick Bonnett knew people at Ohio State. I think this is one thing you find in any profession, doesn't matter what you're in. You turn out students, they go out, and when they find students that they think will do well given the opportunity, then you recommend them to other departments, so they can go on for their graduate work. But at that time, it was the time of the Vietnam War. I had a deferral when I was getting my undergraduate, but when I graduated, I was first in line to go to Vietnam. I got my draft notice, and I actually went to Kentucky and passed my physical. I was within two weeks of being drafted, when I managed to get into the National Guard in West Virginia. Then, I was able to transfer to the Army Reserves here at Ohio State in Columbus, so that I could actually do my graduate work while I did my service in the Army Reserves. So that worked out very well because in the reserves, you have two weeks of training every summer, and then you have the monthly meetings you have to attend. But it allowed me to do both. But within two weeks, I could've been in Vietnam. So it was close. It was a strange time with the protests and all the other things that were going on. But in any event, I was very lucky to get to Ohio State. And so, I started in geology, ended up in the Institute of Polar Studies. But I managed to get my master's degree in two years and my PhD in three years because I had an objective, which was to finish and get a job on the other side. But when I graduated, I was offered a research position in what was then the Institute of Polar Studies. It was kind of 50% university money and 50% from grants. For 15 years, I ran a research program. Because I was told when I graduated from the department of geological sciences, I would never be a professor there because they didn't hire their own graduates. So, I developed this research program in the Institute of Polar Studies that later became the Byrd Polar and Climate Research Center. Fifteen years later, the chairman of what was then the School of Earth Sciences came to see me and asked me if I would join the department. And I said, "Why would I do that?" I really enjoyed the research program, we had a lot of success, and it required that sometimes we drill in three different countries in one year. It was totally consuming, moving six tons of equipment, making sure it was rehabbed before we went out on another expedition, writing papers, doing the science. But we were bringing in lots of resources, federal grants. They wanted me to be part of the school because they were weak in that area. And so, I said, "Well, all right, I will give it a try. But I'm telling you upfront, if I don't like it, and if it distracts from the research I want to do, then I'm coming back to what I do." And they said, "OK." But it turned out to be a good match. I had access to students who could contribute to the programs we were running. I had a flexible teaching load because I told them that if the drilling season in China was in the summer, you have to go into the parts of the world when the dry season comes, so you could go in and do your research. They agreed to that, and it worked out well. And of course, I went on to become a Distinguished University Professor here at Ohio State. But it was never clear, and it was never my objective when I set out.

Zierler:

Who was your advisor in graduate school?

Thompson:

Colin Bull, he was a geophysicist. He was actually the dean of the college of math and physical sciences. I think I was his last student. We'd meet once a quarter for an hour. He'd go over what I was doing and give me an assignment for the next quarter. But he pretty much let me do my thing. I realized later, he was also helping behind the scenes to get me in front of the right people who could make an opportunity for me to run a field project in certain parts of the world. We worked together to get Professor Shi Yafung in China to visit us at Ohio State University as soon as the relations were normalized. I had him when Colin Bull was with me at an IUGG meeting, International Union of Geophysicists, down in Canberra, Australia. I met Professor Shi in 1978. We had these long discussions because I had read in the Journal of Glaciology, about these German scientists who had been in Tibet in the 1920s had seen these ice caps in the distance. And I wanted an opportunity to actually investigate those. And so, at the time, in '78, it wasn't possible to get into China. But then, with Nixon, those relations were normalized, and then it was possible to go in. I was actually in Peru, and I got a request from the National Academy of Sciences to come to a meeting in Virginia about going to China. Because I had been awarded to go by myself for three months in 1984. Of course, I didn't know any Chinese. But it was an orientation program to tell me what I could ask for or couldn't ask for. At that time, you weren't allowed to take pictures in any cities, no bridges. I was given a map by the Chinese government of this glacier I was going to study, and I could not go outside of that boundary. Even on the ice divide for the glacier when it flows down the other side, I wasn't permitted to go across that boundary on the glacier. It was very restricted and very controlled. And of course, there was a lot of, I would say, skepticism. If you work in a country where the dogma for 30 years has been anti-American, anti-US, there's a lot of false opinions and beliefs. So, there was a lot to overcome. But nonetheless, I spent three months there, and the first six weeks were in Tien Shan in far western China, and then the second was in the Qilian Shan on the northeastern side of the Tibetan Plateau. It only took me about a week to find out that in the Tien Shan there was not a glacier where you could get a really meaningful climate record. But in the Qilian Shan, there was an ice cap, Dunde Ice Cap, that we were able to get to. But it was an interesting process because first of all, the Chinese had very little resources for any type of science at that time. They'd just come out of the Cultural Revolution, and the vehicles had flathead engines in them, which were the designs they had before the Communist Party took over, and there had been no innovation. And so, vehicles getting into these remote areas was a real challenge. You had to go in by horseback. I remember working with the Mongols. You have to ride a horse for three days, and these are wood saddle horses and the horses are kind of wild. You'd have to forge rivers that are flooded, so water was coming across the saddle, and the horse's head was up. It was an adventure. And we could only get into this ice cap a certain way because the easiest way, you had to go by one of their nuclear bases and that was off limits. There was a lot of negotiation that went on and building of trust. It was amazing, the lady I worked with at the time, she had been trained in Russia. I remember I brought her to the US as part of our exchange program and took her to Washington, D.C. And when you walk around the capital there, you trigger these recordings that tell you about the capital. And she was looking around on her own, and she was in tears. She said, "They're spying on me." I said, "No, no, no, no. It doesn't matter who walks in front of it, it automatically tells you about the capital." But there was so much suspicion between both sides at that time. Even the National Science Foundation would not fund my logistics in China, the trucks and things that I needed. They would fund the science on the ice cores, but I had to go to the National Geographic Society to get funding for the vehicles that I would need, the logistics in China. And it turned out that at that time, the National Geographic Society was very interested in China and had a long history of involvement. Since they were a private organization, I could raise the money for the expedition from them and at the same time, raise the money for the science from the National Science Foundation. And so, it was very difficult to conduct research in that part of the world. And the whole idea was, why would you use taxpayer money to spend in a communist country? But with time, and building this trust, the National Science Foundation rewrote those rules so that now, people can write a proposal to do research in that part of the world, and they will get their logistics funded at the same time they get their science funded. It was a lot of overcoming barriers and misunderstandings between people and countries. Of course, in more recent times, it's actually gone backwards again, and it's becoming more and more difficult now to get into Tibet for many reasons. But this is the way of the world. These windows, as I say, open and close. But fortunately, when they close, if you've made good relations with scientists, those relations go on. In Russia, I talk to my colleagues, and they're like they were in the 1950s as far as their relationships. They get labeled as foreign agents if they work with Americans. And so, as scientists, you're subject to whatever's going on in your system. Certainly, here in the US, during our last administration, it became very strained working in China. I couldn't believe our last expedition in 2015, having to go through some legal firm in Washington, D.C that went through every receipt, everything that we had spent in China for our project in 2015. Things like, "Why did you have two shipping companies?" "Well, it wasn't our choice that we had two shipping companies. There are certain things you can ship by air, and there are certain things that you can't. And you have to have all that equipment in place in order to run an expedition." So, it's overcoming the challenges that the governments put on you. And frankly, for the National Science Foundation, every expenditure is sent when you do your documentation for every project. But to have to do it for a legal firm, to me, was more harassment. The whole purpose was to discourage scientists from working in that part of the world. And to me, this is not the way to build a sustainable future for all of us. But you deal with what you have to, and you find a way to work around it, to make it happen anyway.

Zierler:

A nomenclature question. Your degree, of course, is in geology. But I wonder if in the mid-1970s, you would've called yourself a paleo-climatologist or even a geophysicist.

Thompson:

Well, geophysicist would've been my title. If you're looking at the paleoclimate history in a glacier, there is the archive in the core, but there's also the physics of the ice, the deformation, the flow that you have to understand in order to reconstruct that record from the ice itself. So, as I say, my advisor was a geophysicist, and that's who I got my degree with. But I would say that what we do is interdisciplinary in every form. I've been really lucky over the years to have such a diverse and dedicated team of people. If you go and look at getting started in drilling outside of the polar regions, this was not an easy undertaking. And the first project, when we proposed to drill the Quelccaya Ice Cap in the Andes of Peru, I had absolutely no idea what I was getting into. I wasn't a mountain climber. And here's an ice cap that's 5,700 meters high, 19,000 feet. I was just naive. I thought, "I'm going to get a drill from Antarctica, and I'm going to get a helicopter, and I'll fly the drill up there with the core boxes. We're going to drill, and we're going to fly that ice core off, and the job will be done." The first time I went to NSF, I was still a graduate student. And there was a fella here at the center, John Mercer, who was a geographer, and before he came there, he made these atlases of the glaciers in the world, northern hemisphere and southern hemisphere. And in order to do that at the time, you had to have aerial photos. So, he had boxes of aerial photos. And it was in those boxes that we found the Quelccaya Ice Cap. I took those to the program manager in Polar Programs, which was the only agency at the time that funded ice core research, and I made the case. And when I finished, he looked at me. His name was Jay Zwally. He went on to work at NASA. But he said, "You know, that sounds like it could be interesting. But you know, I can't fund it. Because it's not north of the Arctic Circle or south of the Antarctic Circle." That was the mandate of Polar Programs. So, when I went to Antarctica in '73, '74, I was really disappointed that there wasn't an agency to get funding to look at ice outside of the polar region. But I think it was in February, I got a telex from the program manager that said, "I have funded all of my real science projects. And I have $7,000 left. What could you do on that tropical glacier for $7,000?" And I said, "I think we could get there." The next summer, we made the first trip there. There weren't directions to this place. It wasn't on any map. But we found a mountaineer, John Ricker in Canada, who had seen the ice cap in the distance. We got him and Cedomir Marangunic, who had just gotten his PhD from Chile. John Mercer and I went to Peru in 1974. When you go to the end of the road, and then you've got to make contracts for horses to get over the divide, and you've got to find the ice cap. But my first view of it, I climbed this peak, and I could see it in the distance, and it went from horizon to horizon. And here you are, in the tropics, right above the Amazon basin, and here's this ice cap. The question was, how would you drill it? First was whether it had a record. So we spent a lot of time demonstrating it had a wonderful record in it. But then, it was, how do you get that record? Well, we tried a helicopter, and we got funding for doing this. Brought the drill from Antarctica, made a contract with the Peruvian Air Force for a Bell 212 twin engine helicopter, which I had read could work at that elevation. However, whether things can work and whether you have the right crew to make them work are two different things. And the crew that we made the contract with was no longer in place when we actually went to do the expedition. And so, we flew the helicopter for 13 hours from the coast up to this little town of Sicuani. We brought the fuel in on a boxcar because there were no airports up there, and we did reconnaissance. But you'd be going along at 19,000 feet, and this helicopter would just drop. We'd have clear air, but there was no way they were going to get near the surface. And all my colleagues were telling me, "You've got to get back in the polar regions. That's where the real science is being done. You don't want to waste your time on this tropical ice cap." And we thought about that, but it was because of the failure of that attempt that we first started thinking about solar power, whether we could drill it using solar power. The beauty was that a solar panel was small. So your restriction was, how many horses could you get together to get that power supply up to that ice cap? But we had to write another proposal to NSF, and we'd just failed with a helicopter. And so, the reviews weren't that good. One of the reviewers was Willi Dansgaard, who was one of the pioneers in the polar ice core work. I had met him many times, and I really liked him. But he reviewed the proposal, and he sent me a copy of that review, and it was very short and simple. It just said, "The Quelccaya Ice Cap is too high for human beings, and the technology does not exist to drill it." In today's world, I think that would just kill your chances. But there was a program manager in climate dynamics at NSF, which was a new program at that time, and he'd just gotten his degree studying monsoons of India and South America. And he looked at it and said, "Well, Willi might be right, but we won't know unless we try." There was an engineer, Bruce Koci, who worked for PICO (Polar Ice Coring Office). He was kind of a free thinker. So, we designed this drill, solar-powered, lightweight. We tested it in a parking garage here at the University on the west campus. Put the panels up on the top, lowered the drill over the edge, brought in five blocks of ice, stacked them, drilled through it. And it seemed to work. But before I left on that expedition, I also passed the exam to enter the MBA program at the business school here at Ohio State because I figured, "All right, you're going to try this again, but if you fail, you better have some options because I don't think you're going to be a glaciologist." But when you're young, you take those risks. And so, we went down, we were actually in Peru for three months, and we didn't have any porters. This was a barebones operation. No cooks, we cooked our own meals. We rotated, carried the stuff up, carried the ice down. And we managed to drill not one, but two ice cores to bedrock. And they were just beautiful records. You could see the annual dust layers, you could date these cores back 1,500 years in the field. And this was part of the world where we knew nothing about climate and how it changed. We didn't have the technology at the time to keep the ice frozen, so we had to cut those samples, 6,000 of them, with a saw, and bag them. We had a special solar tent to melt them, we bottled them, sealed them in wax, brought them back. And although we drilled two cores to bedrock, we'd only proposed to do one. But it was going so well, and we were so lucky that it happened to be an El Niño year, one of the biggest El Niños in the 20th century, where it was sunny every day. And that drill just worked beautifully. I sent one set of samples to Willi Dansgaard's lab in Denmark for the isotopes. And he got so excited about that record that he became our greatest supporter of why it was important to get the histories from these glaciers in the mountains. Knowing what I know about the glaciers around the world, we just lucked out. That glacier is what opened up the whole field that many people now work in. So there's a lot of luck in life, and certainly, we couldn't have been luckier on that particular expedition.

Zierler:

In the mid-1970s, there was concern about global cooling. Did that register at all for you?

Thompson:

It did. I know there was a meeting at Brown University on this very subject because temperatures were going down at that time and a lot of the marginal croplands in the Soviet Union had failed. There was a general concern that we might be going into the next ice age because the inter-glacials, on average, last about 15,000 years and we're 15,000 years out of the last interglacial. Or at least, that's what we knew about it at the time. Now, we have records for ice cores that go back 800,000 years. And we can now see that the orbital forcings that drive the ice ages on this planet were more likely 415,000 years ago, and that interglacial lasted 30,000 years. But at the time, what we knew were that the inter-glacials were short, and the glacials were long and they were averaging about 15,000 years. So, there was a general belief that we may have been going into the next ice age at that time. But we were just getting started, so we weren't really involved in that discussion at the time. Just aware of it. But getting the history of climate and how it's varied through time–and starting in Peru was just fantastic in so many ways, not only because of the uniqueness of that ice cap. And it is unique. There's none other like it on this planet and we've seen most of them. And the other part that made it really interesting is that it's in a place where civilizations rose and fell long before the Spanish arrived. And so, we were able to work with archaeologists and anthropologists, looking at the annual climate history and the rise and fall of the cultures in the Andes, which were driven largely by temperature and precipitation because they were agrarian societies. We could see these 30-year droughts at the time when these cultures collapsed. And it's like most civilizations. We can deal with a few extreme years. But you start talking about decades, then it becomes a real social problem. So understanding that and then looking at the history of El Niños, our observational records are so short. And yet, here you are in the center, where you have the greatest signal of those events occurring off the coast of Peru. And so, there were a lot of exciting things that those first records made possible that we just didn't think possible. When we drilled Huascarán, the proposal we wrote was to get a 4,000-year history. We wanted to double what we got out of Quelccaya. Because neither we nor anyone else believed we'd ever find snow that fell during the last ice age in the tropics. But that's what we found. But you don't know until you drill. And that, I would say, has been the real success story here. We drill in places where no one else has ever drilled. When you do that, the chances of finding something unique, unusual about the climate system are multiplied by a factor of ten. Consequently, we have 14 or 15 Nature and Science papers from those drillings. Because they just changed our view of the world. Changed my view of the world, what I thought I understood. And then, being trained in glacial geology here in Ohio, you have a vision of the world. It's only when you go out and actually study these remote parts of the world, you find that that vision is really flawed as far as understanding how the climate system works. To me, that's the beauty of science. And what you hope when you train students, since you train them to observe and understand the world as we understand it at that time, but you really want them to be able to look at a data set and realize that we may not know everything. That there are new and exciting things out there. It's discovering those that really makes value in science and makes and keeps it exciting.

Zierler:

Between the ice core drilling and your studies of glacial retreat, do you have a specific memory of coming to a realization that what you were seeing was human-caused? Or did that happen gradually over time?

Thompson:

Well, I would say that the beauty of the ice is, it gives you this high-resolution record of both the natural variation in the system and the human-driven side. I would say that the first time I made this connection was in 1991, when I returned to Quelccaya. It was the first time that I actually observed melting at the surface of that ice cap in all the years I'd been going there. When I took a 60-meter ice core record, I got an isotope profile that was a straight line. It didn't have the annual cycle preserved because the water was moving through the porous fern and erasing the signal. It was that and having mapped the retreat of this Qori Kalis Glacier, the largest outlet glacier on that ice cap, that made me realize what was happening there was unusual. Because there had never been a time in what turned out to be an 1,800-year annual history where the record was erased, that melting had occurred, and you lost that annual signal. That's really what convinced me that there was something going on here that was very unusual and led to my testifying before the US Senate on this subject in 1992, the year after making those observations. We had just finished drilling the Dunde Ice Cap in northeastern Tibet. There, we found that isotopes had enriched to the highest level in the last 10,000 years. And so, it was based on not just one part of the world, but having seen it also over in Tibet that we testified before the US Senate. I was part of a group of paleo-climatologists at the time, and there were physicists who studied temperatures in bore holes from drillings all over the world that showed that the heat was coming in the highest temperatures in the surface, and it was migrating into the earth's surface. There were people who studied the output of the sun because that was always one of the nay-sayers points, it was a variation in the output of the sun. But we've been monitoring that since we've had satellites. And there's no increase of output of energy from the sun. If anything, it's been going down slightly at the same time the temperatures have been rising exponentially. So I think there was a combination of things, not only the observations we were making, but observations that other people were making. The tree ring community was seeing unusual growth patterns in the trees. So, science is always on the balance of evidence. You don't want to put all your eggs in one basket. But when you start seeing people looking at the world and using different parameters, different techniques, and you're all coming to the same conclusion, then you have to be concerned. And that really came together for me in 1992.

Zierler:

I'm curious if James Hansen's testimony in 1988 registered with you and was useful for your own preparations for testifying to Congress.

Thompson:

Absolutely. This is a group of people who were looking at temperature records, observational records. And you need all of this. I can remember giving lectures on climate change in this period, might've been at the University of Chicago. I was lecturing, and there was a guy in the audience who brought up that there was an issue with the temperature measurements on the earth, all these instruments we have and the techniques by which we measure it. I told him, "We have over 2,700 stations monitoring the earth." But he said, "They just found out temperatures are rising on Mars." And I said, "How many instruments do they have to document that? Is there one thermometer that's actually documented that?" And of course, there are not. These are algorithms. But the point was that there was so much discussion and bad science. In many cases, it was actually paid science from corporations that saw climate change as a threat to their way of life, their profit, the way they looked at the future. But this is the way science works, people calling into question instrumental records, and you test. Initially, "OK, it's urbanization driving up the temperatures." Well, you get rid of all the urban areas, and you get the same story with the rural temperature records. But each time a question is raised, the science community looks at the data in a different way and tries to determine, "If you remove this particular parameter, do you still see the signal?" But that's the validation of science. And all that was going on in this period of time. But I've met James Hansen many, many times over the years. Eventually, he became more of an advocate of climate change. But he told me that it was clear that it didn't matter how many models, how much data you had. You were not changing the course that we were on. And that's very, very true. Of course, there's always this issue with scientists, where's the line between being the scientist who's doing observing and presenting the information, and being an advocate of the change that you're saying? Scientists straddle this because we're also human beings and we have families. We are concerned about their future as well. My family has said, "If all you do is document the change, and you don't make any changes in the future, in some ways, you're not doing your job." A scientist, I believe, has to be very careful about the data they collect and the observations they make. But I think they also have an obligation, once that becomes clear, to make that generally available to politicians who will ultimately make policy, but also to the public, who ultimately elects politicians. I think we have an obligation to take our research and make it available to these people who will ultimately determine the policy in this country and, of course, globally. But it's not an easy thing. I can remember getting emails from people growing apples in Washington State saying a one- or two-degree warming would be good for their apples. And I'm thinking, "That probably is true. But it's not just apples. [laugh] We have a lot of other things going on in this world." Here in Columbus, sometimes we have pretty cold winters and inevitably in February, you get a cold outbreak, I'll get emails saying, "Where is this global warming? I'm freezing my ass off here." [laugh] So you just have to roll with the punches.

Zierler:

Regardless of the political ramifications of the research, what are the values in taking ice core samples all over the globe, both in terms of the similarities in what you're finding and the differences in what you find?

Thompson:

Well, I think that first of all, if you just sit back and look at the planet, look at the complexity of climate on this planet, if you want to look at variations in the monsoons, you're not going to go to Greenland or Antarctica. You're going to go to the Himalayas. That's where the signal's going to be preserved. And monsoons impact the livelihoods of billions of people. How has that varied through time? What's the natural variation through time? First of all, to me, it is being able to record and evaluate the various aspects of our complex climate system on the planet. We're all impacted differently by those. Some people argue, "Why are you looking at ice in Peru?" Well, because every El Niño impacts the climate here in North America- whether you'll get snow in the Sierra Nevada range, whether you're going to have water resources. The tropics drive the climate on this planet. It's where the heat comes in, and the water vapor's evaporated from the oceans. And they get distributed north and south from that zone. So, we really have to understand that. It's in our own best interest to understand that. So, I think that this global picture is extremely important because yes, there are different signals in different parts of the world, but they're all connected. The ice core records that we get from the polar regions, these are extremely important because of the length of that history and the fact that you can actually look at how carbon dioxide varies in our atmosphere for 800,000 years. These are little time capsules of our atmosphere. And then, you can look at the proxies for temperature, deuterium or the isotopes of oxygen that are preserved in that same ice. What you find when you do that is, carbon dioxide is a very important part of the story of the climate of this planet, and it always has been. If you come along, as human beings, and suddenly you have the technology to mine all the trees that have grown on this planet over millions of years in the form of coal, and oil, and gas, and you're able to release all that suddenly into the atmosphere, you're going to change the climate of this planet. Because that is a big driver. As a species, we're extremely clever. The fact that we can do that and do it at such a magnificent rate–but that's just forest where the natural system had archived that carbon, taking it out of the system, and we just put it all back at once. And we have to change that. I've met with a lot of oil companies. These are smart people—we need those people also working on this issue of how we transition from being fossil fuel companies to being energy companies for the future. This whole planet has run on solar energy for millions of years. We just need to be a little cleverer how we capture it in all its forms, how we store it and distribute it. These companies have worked on this using fossil fuels, the distribution system for the planet. And in fact, I would argue that if you don't make this transition, you won't be here 50 years from now. But we all have to be part of making that difference. So, I think that what is clear is that the system itself is telling us louder and louder that we have to change. We're going to have to do things differently. And we can. Humans are, in so many ways, a remarkable species. We have never let anything stop us. Mountains, oceans, even space. And we will make those transitions. But we have to preserve this unique place that is our home. And clearly, at least up until now, we don't have any good alternatives of where we could go if we mess this place up. Of course, even if you could go to another planet, you're going to have to be very wealthy in order to afford to get on one of those transport ships. Most of us are going to be left on this planet to deal with maintaining this home as we know it.

Zierler:

When did you realize that Al Gore would be an ally in getting the message out, and what was your involvement in An Inconvenient Truth?

Thompson:

I would say it was interesting. I first met him when I testified to the US Senate in 1992. And he, at the same time, had just written a book on the environment, so I knew that he was really interested in this subject. He was really trying to come up to speed. So, after I testified, we stayed in contact. Then, when he became Vice President, he invited me to a breakfast, where we talked with the heads of different agencies about what was taking place. But he also told me that he actually had more say on making policy changes as a Senator than as the Vice President. Because as the Vice President, there's a platform that you get elected on and at the time, I think climate was number 11 or so. Essentially, you end up dealing with the top two things on that list if you're lucky. But he was genuinely interested and learning. I remember when he lost the election for the presidency, he called me, we had a long chat about democracy and how it works. And when did it work best. I remember him saying that he thought it worked best when we had newspapers where people would get together in cafes on Sunday afternoon and discuss a story, the pros and cons, and there was real communication taking place. And in today's world, we have hundreds of means of communication, but very little communication. Because people listen to things and people who think like they do, and they're not really trying to understand the other side of an issue. I think there's a lot of truth in this, that we do have so many forms of communication. All you have to do is talk to any reporter or TV person to understand that all these different communication companies are struggling with how to reach people in today's world. How many of these different social media platforms do you use to get a message out? So, communication, to me, is critical. But I can also say that I've been amazed even at universities, that after the election, when I had this long conversation with Al Gore, he just mentioned that he wouldn't mind coming to Ohio State to give a lecture. I said, "I think that's a great idea." When we finished talking, I called our vice president for research to tell him that we had an opportunity here, and I thought we should make it happen. It wasn't very long after that communication that I started getting emails from people who said, "You need to meet with university lobbyists about this invitation." I said, "No, I'm not meeting with any lobbyists about an invitation. The question here is whether Al Gore's going to talk at the Byrd Center or give a university lecture." So, they set up two meetings, and I didn't go to either of them. One evening, I got an email from the then-president of the university, Karen Holbrook. She said, "Lonnie, I hear you've been trying to get Al Gore to come. I want you to know that I'll make the President's House available. Let's make it happen." And so, we did. And the beauty of that was, when he came, he gave a public lecture. You had to get a ticket to go. You didn't have to pay for it, but you had to get a ticket because the lecture hall would only hold so many people. Two weeks before his lecture, all the tickets were gone. And he gave a wonderful lecture. He also did a fundraiser for the university. And I remember talking with some people from the opposite party who said that had they actually met him, they might've voted differently. But they had a vision of this guy which was totally controlled by media. We're subject to that today in the way we see our politicians. So, I learned a lot from interacting and from my community because I got emails from people like Wasserberg at Caltech saying, "Lonnie, how could you possibly work with a politician to produce a film about climate change? This is the guy who invented the internet. You need a climate scientist, someone who's spent 30 years studying this." I said, "The problem is, you make a movie with a climate scientist, no one's going to come. You've got to have a messenger. And he wants to get it right, and I think as a science community, we need to try and make sure he gets it right as far as we know it at the time." so there was a big discussion within the community. "Should you do this? Or should you not do this?" I remember being on a flight coming out of China, and the plane I was supposed to get on was diverted because of a typhoon. I was on a Japanese airline. And everybody's in there, and we sit down, and a movie starts. And it's An Inconvenient Truth. I said, "This is the way to do it. You have an audience here, and they can't get out. And they have to listen." [laugh] Over the years, as I've lectured around the world, I've often asked, "Have you seen An Inconvenient Truth?" And inevitably, everyone has seen it. I think it had a bigger impact outside the US than in the US. In the US, it became a political issue. I remember even with some of the groups we have come in for tours, conservative groups that we talk to, and I asked one of these conservative groups, "How many of you have seen An Inconvenient Truth?" No one raised their hand. I said, "Had that movie been done by John McCain, would you watch it?" And they said, "Yeah." And at the time, John McCain was very much concerned about climate change. So, I thought it just kind of tells you where we are. The messenger is very important, who delivers the message. And frankly, I've seen this when my wife and I got back to West Virginia. A number of years ago, they had a special lecture in the Clay Center in Charleston, the capital. This is coal country. So, we were ready to give our lecture, and they had to delay the start because there were so many people lined up to come in. The lecture had to be delayed 15 minutes so they could get everyone into the lecture hall. I think the difference here was the messenger. We grew up there. We're not outsiders, to them we're not academics, we're one of them. Therefore, I think, a lot of whether people listen or don't listen to a message depends on where they're coming from. And part of communicating is understanding that and making sure you've got the right messenger to reach those people.

Zierler:

What was it like to win the National Medal of Science?

Thompson:

Well, I must say, I had mixed feelings on this at the time. In fact, I had emails from people who said, "There's no way you can accept this because it's going to be given by Bush." I thought, "Well, they have a point in some ways." Because he was certainly not promoting climate change. A lot of things that were going on were anti-climate change. But it was my daughter who actually convinced me to go and accept it. She said, "Dad, this is really important. Because he has to give it to you."

Zierler:

[laugh] Whether he likes it or not.

Thompson:

That's right. [laugh] And so, I did. I remember it was certainly an honor, but I was also thinking, "What have we come to? Here's a guy who studies ice, and he's getting the National Medal of Science." Dr. Fauci was one of the recipients that year of the National Medal of Science. But it was a diverse group of people, and certainly I was honored to receive it. But I've been very fortunate over the years to receive lots of awards, and they're all special in their own ways. But I think one thing the awards allow is that an audience maybe listens a little closer to what you say, you can maybe make a little bit more of an impact. The other part of it is, of course, I'm part of a team. I have always felt that awards are really a team recognition. We've been fortunate to win a number of awards that have money associated with them. Those funds go into an endowment to support the team. Because again, I don't consider it personal, I just feel very fortunate that I've been able to find what I'm really passionate about and have the opportunity to pursue that for a whole career. Very few people have that opportunity. And so, I'm honored to receive them, but I don't take it personally.

Zierler:

On the question of being part of a team, what has it been like, given the fact that your closest collaborator is also your wife?

Thompson:

Well, it's good and bad in so many ways.

Zierler:

Are you allowed to talk about ice at the dinner table?

Thompson:

In fact, we often do because if we're working on something that's really exciting, we share that. And the other part of it is, Ellen has run expeditions to Antarctica and Greenland, so she understands when I have to go away for two or three months. I would say that a lot of spouses might not take kindly to that, especially when it occurs repeatedly year after year. So, there's an understanding there on both sides. We raised a daughter, and because our expeditions are in different seasons of the year, one parent was always there. And I would argue that my relationship with our daughter is much closer because when Ellen was in Antarctica, I would be doing the PTA, the social events, and be really involved in her life. And so, I always felt that raising a child was like a 20-year experiment. You didn't know whether you were doing it right until you see the product that comes out the other end. And we're very pleased with our daughter, and she now is in executive management in the FBI in Washington, D.C. She currently heads victim services for the agency. She's really good at what she does. And we always told her that we didn't care what she did, what area she went into, only that she really was passionate about what she did. Because that's where the enjoyment of life comes from. I think she's found that, so we're very pleased. I think we've always seen everything we do kind of as a team effort. And we want to have a good product when we're finished.

Zierler:

With all of your committee appointments and advisory work, what stands out in your memory as being most advantageous, first for the platform it gives you to talk about your work, but then also for the networking opportunities to engage with other scientists who are engaged in the same questions, albeit from different fields?

Thompson:

That's a hard one. I think you reach different people using different platforms. Certainly, as a professor, one of my greatest rewards is finding that while you're giving a lecture in Florida or California, you encounter someone you taught in an undergraduate class and you still remember and now they hold a good position. In our environmental science class, sometimes we'd have up to 120 students, but they remember you. Some of them will tell you that they had a lecture that changed the whole course of their career. Suddenly, they became interested in the environment and in making a difference. To me, certainly, that's one way to make a difference. But you don't reach so many that way. If you're going to change the tide, you have to reach millions. And how do you do that? It was probably ten years ago or so, my daughter said, "Dad, one more ice core is not going to make a difference." I thought about it, and she was absolutely right. It's not going to make a difference. She said, "You've got to do something else. You've got to write a book, make a movie. You've got to reach millions." And so, in part, as a result of this, and part of it has to do with opportunities, we're just finishing a one-and-a-half-hour documentary called Canary. It's being produced by Boardwalk Films out of Los Angeles. But it was more the intersection of two different ideas. A producer who had gotten his PhD degree at MIT in neuroscience and who had worked three years as a post-doc in a Nobel Prize winner's lab decided that he wanted to communicate science to the general public. He wanted to inspire the next generation of young scientists. And a photographer who produces Chef's Table on Netflix is also involved. They had this idea, and they got funding from the Sloan Foundation to explore telling the story of a scientist. Their vision is to have a series on Netflix, or Amazon, or somewhere that tells the story of a scientist, how they became a scientist, kind of their life story. They interviewed, I think, 350 scientists. They went in the field with eight. And they chose our group to try this. They see it as their “Quelccaya.” But the whole idea is to tell the story in a way that will influence young people to think about science careers. We would be one in a series if it actually works out. A couple weeks ago, I saw the first cut of the film. They now have the sound. The composer scoring the movie also composed the last Star Trek film score. I have no idea how this will all work out. I don't think anybody does. But it is an attempt to reach millions of people. Whether it will succeed or not, no one knows. But from my perspective, it has already succeeded. Because in this film, they were fortunate to film not only my story, but they were able to interview my daughter, and up until her recent promotion, she was not allowed to be on TV. But now, she's part of the film. They interviewed my mom, who is now 93 and suffering from bone cancer. They interviewed her while she was still able to tell a story about my early life. And they were able to go to Peru and China with me. All of that is brought together in this film. There's another part of my story that has a human connection, and that's the fact that a little over nine years ago, I had a heart transplant. I had a less than 10% chance of surviving, but I got the transplant. Before the transplant I had an LVAD, a left ventricle assist device, which they put into the old heart when they put me onto a transplant list. This is a turbine that actually circulates the blood. For almost nine months, I operated on a turbine. I had a computer that I wore in a vest that drove the turbine. During the day, it operated on batteries, and at night, it was plugged into the wall. If there was ever a disruption in that power source, the heart would stop. So, it really gives you a whole different view of a dependable power supply. [laugh] But that was my bridge that bought me some time for them to find a donor. And while I was on this bridge, my wife and daughter came to me and pointed out that I was alive and functioning. I had a special waterproof container I'd put the computer in when I took a shower. And they said, "You're functioning, and you're working. Do you really want a heart transplant?" And I said, "I've had 63 great years. I wouldn't change a thing. And if I could have a few more great years, then it'll be worth it." And so, I got the transplant. Since then, I've been able to set an altitude (~ 22,000 ft record for a transplant patient) while drilling in the western Kunluns, and then in 2019, we drilled the highest tropical mountain on the planet. But part of that is overcoming obstacles. I would say that's probably the story, if there's a story in my life. Overcoming obstacles. When it looks like it's impossible, and everyone gives up, you don't. You keep going. In that regard, I feel extremely fortunate. I've run six expeditions since the heart transplant. And there was a time when I couldn't walk from the hospital bed to the door of my room. When they produced this film, the producer said, "An Inconvenient Truth went for the head, the brain." They wanted to go for the heart, because it's how you reach people. The message of climate change is there. But it's a story that, hopefully, will keep people who would normally not listen engaged. So, I figured it was worth the effort. I had no idea how much effort goes into making a film. But I have a much better appreciation of films now. In so many things in life, it's that way. Last semester, I did a TEDx talk. I have never put so much effort into a 14-minute talk in my entire career. It's all about getting it down to the message, and nothing more. It's so hard to do that. That talk should be released here in the next couple weeks. Again, it's aimed at reaching many people. So how do you actually make a difference in this world? My feeling has always been that if everyone does what they can, they will change the world. We just have to do our part.

Zierler:

Sometimes in journalistic accounts, you're referred to as an environmental hero. Now, as a political activist, what do you find valuable about that moniker, and as a scientist, what perhaps is problematic about it?

Thompson:

Well, I've always felt heroes are more a function of who's telling the story. I can look over here at this case with awards from all over the world. But when I look at the CO2 record and temperature record of this planet, I say, "No, I haven't accomplished anything yet because we haven't changed the course of our future." To me, it's about changing a trajectory for all of us. But that is a failure in my book, in that I always thought that when the data is so compelling you can't walk away from it, we would make the right choices. But it's not just the data. I think you need the data to make the statements. You have to be able to back it up. But that does not change the course. And so, as a scientist, I am intrigued, and I go with the data. But as a human being, that's not enough. I figure we only have a certain amount of time to make a difference. Frankly, I felt very fortunate in 2019 while climbing Huascarán. We had to go up an ice cliff that was 600 meters, almost straight up. I was 71, and I'm thinking, "It's amazing that I can even go up this mountain at this age, let alone go up there, drill ice cores, and sample them." So, in a way, I feel extremely fortunate. There was a lot of discussion when I had to get a heart transplant whether my lifestyle contributed to that. When they were doing the operation my oxygen levels in the blood dropped below where, in a normal person, the kidneys and liver would've shut down. But mine didn't. And the only thing they could think of is I have spent a total of over four years of my life above 18,000 feet, and those organs just thought they were back on a mountaintop somewhere. [laugh] You never know in life the things that might come back to serve you in a way that you never even thought of. So, I think the important thing is just staying true to your mission. I'm very, very passionate about what I do. I certainly don't see myself as a hero. I do see my field teammates as heroes because I've seen them under such awful conditions. There are a thousand reasons why we should have failed. And yet, somehow, we persevere and succeed.

Zierler:

Between your affiliations, both in Beijing as an Adjunct Professor at the Center for Excellence in Tibetan Plateau Earth Sciences, and as Co-Director of Academics at the Tibetan Plateau Research Institute, what are some of the values in these strong partnerships in China, given that China's carbon emissions are so great in the world, but also that China potentially has the technology and capacity to offset that with alternative energy sources?

Thompson:

Well, I think there's a role to play there. Clearly, China realizes there's not enough oil, gas, and coal in the world to support their 1.4 billion people. The fact is, for all of us, these are limited resources. How limited is up for debate. But they are limited. And their environment has gotten to be so bad with pollution in some of their cities that companies are no longer moving to China because they didn't want their families and workers exposed to those conditions. They've been kind of forced into the mindset of, "If you want to continue to develop your economy, you're going to have to take care of your environment. And you're going to have to make it so people can survive in it." And we've all learned that lesson. Some of us earlier. London and Pittsburgh are past examples. All developed countries have gone through this. But it's clear that China is putting a tremendous amount of resources into alternative energy. They see this as a future. The only way forward. I think that if I look at the world as a whole, there are several countries that run on oil. Their only economy is oil, and it's usually not good for them. I have a feeling that China may actually lead for a while in renewable sources of electricity because they are putting resources into developing better solar cells, better wind power. And the beauty of science and technology developments is that these things tend to get shared. It's clear that here in the US, megawatt production of solar and wind energy is now competitive, and in many cases, cheaper than fossil fuels. Economies will drive that transition going forward. But I look at some of our attempts to get on the same page in the world when it comes to sustainable ways forward, and I've often felt that it's hard to get 180 countries to agree on anything. But if you could get the US, China, and India, the big economies, to decide on certain standards, those standards would then become global. Because it's kind of like California. If you have a high standard for cars on emissions and gas mileage, if you're a producer of cars, you have to meet those highest standards. Then, those become available to everyone. I believe in all the countries we've been to, such as China and in South America, there are things to learn from the people we work with. And they can learn from us. China has a long history. And like every country, they're fortunes have been up and down. But we can learn from that. We can also learn from the indigenous people in South America, who farm seven different fields at different elevations. If one field fails; they still have six more. But I look at a country like Bolivia and their capital, La Paz, which is down in a valley and dependent on water that's becoming more scarce. Then I look at the little village at the base of the Sajama Mountain, that had been there for 3,000 years. And if you ask me which one's going to be there 500 years from now, I'll put my money on the village. Their lifestyle is sustainable. They've learned that you can only push the environment so far. We can learn from that. We can learn from the Chinese because they have a long history. And I think you have to look at all people on an equal basis. Yes, they can also learn from us. I think that mutual respect is how you can bring about change.

Zierler:

In just five years, you can mark your 50th anniversary with an affiliation at the Byrd Polar and Climate Research Center. In what ways has the Center changed over the years, and in what ways has it remained the same?

Thompson:

Well, as I indicated, when I started it was the Institute of Polar Studies. It focused mainly on Antarctica and Greenland research. It was actually founded as a short-term institute to give people who had worked with IGY, International Geophysical Year 1958, three or four years so that researchers could write up all their measurements and publish their papers. But as it turned out, there was a long-term interest in polar regions and in cold climates. But I would say that the big change I've seen is, the programs have become more global in nature. We still have programs in Antarctica and Greenland, but we also have interests in many different aspects of the climate system, water, temperatures of alpine regions. I would say that cold is still a theme, but it doesn't matter whether it's high latitude or high-altitude regions of the world. My assistant, here, is interrupting. This is Abby.

Zierler:

[laugh] Hi, Abby.

Thompson:

She's the newest member of our family. She's a rescue dog. We have only had her for about three months. But she is a good little girl.

Zierler:

At the beginning of our talk, we talked about your current interests. And so, for the last part of our talk, I'd like to ask one broadly retrospective question about your career, and then we'll end looking to the future. To go back to the interesting comment your daughter made about whether one more ice core will matter, I'm curious, given all of your work in the field, all over the globe, and the value in seeing the data confirm itself over and over again, what sticks out in your memory as being most surprising in the data?

Thompson:

That's a difficult one. There are so many aspects. I would say that probably one of the first things that really took us aback was when we were processing the 20,000-year old core from Sajama, Bolivia. In the lab, as in a segment of ice began to melt, two eyes suddenly appeared, and it turned out to be an insect. It was totally preserved, and it turned out to be about 5,000 years old. Of course, the type of insect can provide you a view of the world at the time when it was living, but it also can provide you an independent carbon-14 date for the ice core. And since then, we have found a number of insects and plant fragments in these tropical cores that can also be used to date the ice and tell us something about the environment in the past in these regions. But I would say that first of all, finding the “little ice age” in the tropics in the Quelccaya core was the very first one. It was the first documentation of the little ice age, which had been found in records of glacier advances in Europe and North America, but never before in the tropics. No one expected to find that. We never expected to find such old ice. And the documentation of monsoon failures hundreds of years ago in the cores coming from the top of the Himalayas were amazing. But we'll see how old this new ice core from western China is. It could give you a totally different perspective. Also, how does the methane record develop for the cores above the Amazon? When we started in this field, we were the very first group to look at dust in ice core records. Dust was the only thing we measured. I remember when I first presented this to the polar community, one of the pioneers in that field took me aside the night before I was to present and told me that if I told this community that you can date ice cores using annual dust layers, my career would be over. I was still a student. I remember going back to my hotel at 3 o'clock in the night, worrying about this. I thought, "Well, I came here, and that's what I was going to say. I'm going to say it. Maybe it's the end of my career." But it wasn't. In fact, it later became one of the techniques used in labs around the world to date ice cores. But since then we expanded, and we now measure isotopes in precipitation, chemistry, and radioactivity. Many of the thermonuclear bomb tests that humans have made on this planet have left residue in the layers of these ice cores, and they become time markers because we know when those tests took place. The ice just preserves everything in the atmosphere. More recently, we are looking at microbes and black carbon to determine if bacteria and viruses have evolved with time and the fire history of the Amazon. We're concerned about fires in the Amazon today, but if you look over 20,000 years, how did that change? That’s one thing the cores do—provide you this perspective that you can't get from any other source. It allows you to measure so many different things since if it's in the atmosphere, it can be archived. I would say the other thing that continues to amaze me is the reproducibility of these records. You can go back to one of these glaciers a quarter of a century after drilling it, and if it's high enough and it has remained cold, you will get the same record that you got 25 years earlier. And it just tells you that the archive is working, and it's beautiful. Our only limitation is how we interpret what it's trying to tell us. It takes me aback to see just how reproducible these records are. And I don't think there are too many archives that we have that behave in that way. The other thing is that ice is not alive like a lot of other archives are, like trees and corals. Anything that's alive can adapt to a changing environment. But an ice body is just a physical record of what was in the atmosphere, preserved in time. I think in that regard it's a faithful recorder of changes in the environment.

Zierler:

Last question, looking to the future. In surveying your career, it seems as if you've left no stone unturned, or as it were, no ice core left un-drilled. What remaining work is to be done, and what advice might you give younger people in the field who are charting their course?

Thompson:

Well, first of all, I would say that you don't want to go down the same road that I've gone down. I have this discussion with my graduate students. These glaciers are going to be gone. I think in any area, even in the polar regions, you have to ask the question, how many cores do you need? Another question is, what are the scientific questions that you could answer if you had those cores? Fortunately for young scientists, our ability to measure things that I never even conceived of when I was starting my career now exist. For example, to be able to identify bacteria based on its DNA. By some accounts, at least, over 40% of the biodiversity on the planet are organisms we can't see. And yet, they're preserved. There's a history of them in the ice and how they evolved, how this evolution took place in these basic organisms that are part of our system. Before my heart transplant, I got one of these MRSA infections which almost killed me. It wasn't the heart transplant. That was easy. It was the infection. If the world has learned anything in the last year, these microorganisms can do a job on us. We need to understand them better and understand how they evolve, how they mutate, all of these things. But to me, it's asking the new question. You can always justify an ice core if you have a relevant question to ask that an ice archive can address, assuming that the archive is still there. This is the other part of this whole story, that at least for most of the mountain glaciers, we are going to lose those archives, if we haven't already lost them. But there's another story, and this is where, I think, timing is so important. The ability to go in and get these cores, get all the permits that are required, get those records out of those places, I believe, is getting harder and harder. And part of this is because a lot of the places we work are now national parks. They come with a whole new set of regulations. There have been laws passed, for example, in Peru that locals are not allowed to go up to the glaciers and take pieces of ice anymore. Up until 1992, this was a way of life for some people. Before there was refrigeration in the tropics, people would go up, take blocks of ice, put them in an ice house. Glacier ice is also considered by local people to be medicinal for diseases and the like. However, a government like that in Peru that gives a foreigner like me permits to go and take those cores, not only off the mountain, but to another country. Then it becomes a more complex story. So getting permits to work in these remote parts of the world have become more and more difficult with time. And there are all kinds of reasons for that. So, there's a challenge there, there's a challenge in the fact that the ice is disappearing as we speak. But there are ice caps on Mars. And some of them are estimated to be over eight kilometers thick. What a marvelous history. In fact, if I was going to Mars, I'd be drilling an ice core out of one of those polar ice caps. But you think about the ability to look at forcings of climate on a planet that doesn't have an ocean, that makes that understanding more complex. We were part of a project with JPL to actually attempt to drill in the northern ice field of Mars almost 3 decades ago. And I was amazed. When you look at the technology like a mass spectrometer, they weigh a ton. We have them in our lab. But if you want to measure isotopes on Mars, you can put a mass spectrometer the size of a quarter down the borehole because you don't have to create the required vacuum to make those measurements. For a regular mass spectrometer, most of what it does is create a vacuum. And I say, if you want to look for evidence of extraterrestrial life, it's going to be preserved in those polar cores. So, there's a future. There are icy moons out there and all kinds of issues to address that go beyond our earth system. But I also think that the future in science involves understanding the impacts of how the changes in the water resource that these glaciers represent are going to impact local people. Because they depend on them for drinking water, for irrigation, for hydroelectric power, and they're all at risk. And one of the big unknowns we have is a good understanding of the volume of water that's stored on these mountaintops. How much water do we have? How long is it going to last? As far as being able to determine the volume of ice in these really rugged terrains, you can't really do it from a satellite because the footprint is too big. But how do you do it on the surface of the earth? Well, during our last two field projects, we mapped the bottom of the glaciers using new GPR systems. So, I think it's understanding the questions that need to be answered, and those that need to be answered that impact human beings and what science can contribute. We're still struggling to find effective ways to take what we've found in the ice core from Huascarán and translate that into information that would be useful to the indigenous people who live right at the base, and depend on that water, and in some cases see that mountain as a sacred place. How do you take scientific knowledge and turn it into a practical product useful to people who depend on those glaciers? I think these are areas that really need to be developed going forward. When people can see that they're personally going to benefit from whatever's being done, it becomes more doable.

Zierler:

Lonnie, this has been an absolute delight spending time with you. This is an instant historical treasure for our archives. You talk about the archives in natural systems, I think about the historical archives, and this is going to be one that's a treasure for generations to come. Thank you so much for spending this time with me.

Thompson:

Thank you so much, David.