Coronavirus and climate change

The coronavirus pandemic stay-at-home orders and lockdowns resulted in a huge drop in global greenhouse gas emissions — the largest reductions since World War II. The reductions were short-lived as the U.S. and other countries opened back up, but there are lessons we can take away from the pandemic about global climate change and how we’re handling both crises. In this episode of Unfold, we look at surprising similarities between the climate crisis and the coronavirus pandemic.   


In this episode:

Fraser Shilling, co-director, Road Ecology Center at UC Davis

Ben Houlton, affiliate faculty member, former director of the John Muir Institute of the Environment at UC Davis

Helene Margolis, associate adjunct professor in the Department of Internal Medicine, UC Davis School of Medicine

Tracey Goldstein, associate director, One Health Institute at UC Davis



Amy Quinton Hey Unfold fans. Welcome to a new season of episodes. This time, we also have a new co-host. It's Kat Kerlin. Hey, Amy. Kat joins us also from our news team here at UC Davis. 


Kat Kerlin Yeah, I'm really excited to be here. Thanks, Amy. 


Amy Quinton She brings with her a wealth of experience covering the environment, which is great for this season of Unfold, because we're focusing on what one could argue is the biggest challenge facing the world right now. And that's climate change. 


Kat Kerlin Whoa. I could have sworn you were going to say coronavirus. 


Amy Quinton No doubt coronavirus is at the top of everyone's mind. It seems a never-ending challenge. But Kat, as we all know, climate change hasn't stopped just because so many of us are still sheltering in place or at least avoiding crowds. In fact, one of our researchers here at UC Davis put it this way. 


Fraser Shilling We have a viral crisis right now, but the climate crisis isn't going away. 


Kat Kerlin Who was that? 


Fraser Shilling That was Fraser Shilling with the UC Davis Road Ecology Center. I interviewed him, via Zoom from my closet during the beginning of the virus when practically everything was shut down. The closet, you know, it seemed like a safe space and it still seems like a safe space. 


Kat Kerlin Ah, yes. Fraser released a study that showed all those stay at home orders resulted in a huge decrease in traffic and greenhouse gas emissions, which are, of course, the gases that cause climate change. You can read about that report on our Science and Climate website, 


Amy Quinton Nice plug, Kat. 


Kat Kerlin I try, but that study highlights an interesting point. There is a connection between coronaviruses and climate change. 


Amy Quinton There is. And we're going to have more on that study in a moment, because in this episode of Unfold, we're going to be looking at the connections and similarities between climate change and COVID-19. 


Kat Kerlin To name just a few: They're both huge global problems. They both affect the world's most vulnerable populations. They both involve bending or flattening a curve. 


Amy Quinton [And dare I point out all of the negative similarities? 


Kat Kerlin It's hard to stop you from pointing out the negative, Amy. 


Amy Quinton You're right. Both crises also show us how inadequately prepared we are for disasters, how we politicize or flat out deny the science and how bad we are at anticipating the consequences of our own actions. How's that? Is that negative enough? I could go on. 


Kat Kerlin No, you can stop. We're also going to talk about the lessons we've learned, at least so far from this pandemic that might help us in the fight against climate change. 


Theme: Coming to you from our closet studios as we shelter in place across the Sacramento region, this is Unfold, a UC Davis podcast that breaks down complicated problems and discusses solutions. I'm Amy Quinton. 


Kat Kerlin And I'm Kat Kerlin. 


Amy Quinton This week we unfold climate change and COVID. So, Kat, let's just bring people up to speed on what a wonderful world it's been since our last episode of Unfold launched last year. 


Kat Kerlin Yes, 2020 got off to a great start. 


Amy Quinton Right. I was busy writing all these fascinating stories about climate change for this upcoming season. I even traveled to Africa in January to cover some of our research going on there. And I get back and I hear this. 


News Clips A new virus appeared in the Chinese city of Wuhan last month. 


Amy Quinton And from there, as you know, it escalates. 


News Clips Autopsy show that two people who died in Santa Clara County on February 6th and the 17th tested positive for the virus. 


News Clips How many Americans will die from COVID-19. At this point, we just don't know. 


News Clips He held a rally. He didn't mention the virus during his speech. And in a local TV interview that night, he said, I think it's going to work out fine. 


CA Governor Gavin Newsom That testing number may sound high to some. It is low to many others. And certainly to me. 


NY Governor Andrew Cuomo To have this happen over this weekend is really, really especially tragic. And they are all in their thoughts and prayers. 


News Clips Because this virus is new to science and new to humans, we have no idea how long immunity is going to last. 


News Clips As we know, supply chain issues have made it difficult to have the proper protective gear. 


News Clips And some fear the administration might cut corners to meet that ambitious schedule as a way to gain a political advantage. 


News Clips Attendance will be limited and everyone will be required to wear masks. 


Amy Quinton [We all know that climate change did not cause COVID-19, but certain human actions on this planet are creating a world where pathogens like coronaviruses are more likely to spread. 


Kat Kerlin That's right. Both climate change and habitat destruction can make animals and humans more susceptible to infectious diseases while also bringing animals into closer contact with humans. 


Amy Quinton So you might ask, how can this happen? How can climate change lead to the spread of viruses or other types of pathogens in animals or humans? I talked to Tracy Goldstein about this. She's the associate director of the One Health Institute at UC Davis School of Veterinary Medicine. 


Kat Kerlin She led a 15-year climate change study that found that the melting of Arctic sea ice unleashed this deadly virus for marine mammals in the North Pacific. It's called Phocine Distemper Virus, or PDV, and it was found in sea otters, northern fur seals and steller sea lions. 


Amy Quinton The virus itself isn't new. It's part of the same genus of viruses that cause distemper and dogs and measles in humans. PDV also has been in marine mammals before, but only in the Atlantic Ocean, not in the Pacific. And Tracy says it's deadly, particularly for harbor seals. 


Tracy Goldstein Harbor seals are really, really susceptible. And in fact, in 1988 and 2002, this virus was estimated to kill about 50 percent of the population in harbor seals. So very, very easy to transmit between animals and just huge mortality rates. So the concern was that we suddenly saw this virus in the Atlantic, you know, move into the Pacific, into an area where we know they are potentially really susceptible populations that have never seen that virus. And so we wanted to try to understand wasn't circulating how susceptible were animals, was it causing deaths? 


Kat Kerlin So researchers began to examine the differences between the outbreak in '88 when the virus did not show up in the Pacific, and in 2002 when it did. 


Tracy Goldstein And the difference was in '88, there was really good ice cover in the Arctic and likely not channels for animals to move. But in 2002, there was really one of the first really dramatic years. If you take a look at the sea ice data of a huge reduction in sea ice, and since that time, we've seen that in many other years. 


Amy Quinton Their analysis found infection peaked in 2002 and 2003 and then again and 2009. 


Tracy Goldstein And the two things that were consistent both those years was the ice channels were open in sort of the year before when we saw the peak. And the concern is now is in since 2008, really, there's been open channels and ice every single year since that time. 


Kat Kerlin And that raises a lot of concerns, not just for animals, but for humans, too. 


Amy Quinton Right. Because we're talking about landscapes changing on a massive scale. Tracy mentioned to me that with less Arctic sea ice, ships can now reach places they haven't been before. 


Kat Kerlin And we've deforested large swaths of land as our population expands. And all of this is bringing more people into contact with wild animals that can change the distribution of viruses and bacteria. 


Tracy Goldstein The contact between people and animals is changing. It's becoming more frequent. It's becoming more intense. And because of that, I think that's what's leading to these spillovers and potentially more of them more frequently. 


Amy Quinton What scares me, Kat, is the potential for zombie viruses. 


Kat Kerlin Mm hmm. Whoa. What? 


Amy Quinton Yeah, scientists actually call them that. As the Arctic warms twice as fast as the rest of the world, the ground, you know, the permafrost is starting to thaw. It could unleash all sorts of microbes and viruses and revive long dead diseases. Some of the bodies of the 1918 flu pandemic are buried there. Of course, we don't know if any of the viruses can survive. But I read that the bacteria anthrax can survive as well as tetanus and botulism. And then there are all those viruses that we've never heard of. 


Kat Kerlin There you go again, Miss Negative. 


Amy Quinton Sorry. Well, another negative and another link between climate change and COVID is the people who are affected the most. 


Kat Kerlin We saw with the coronavirus that in most communities, the poor, the elderly, people of color were the people most affected by COVID-19. 


Helene Margolis I knew ahead of time who was going to be the populations most at risk. 


Amy Quinton That's Helene Margolis, an associate adjunct professor in medicine and the Department of Internal Medicine at UC Davis. 


Kat Kerlin She's also with the John Muir Institute of the Environment. She expanded on who she thought would be most at risk. It turns out it's the same populations that are most vulnerable to climate change. 


Helene Margolis Underserved and under-resourced communities and unfortunately, in this country, it's most often people of color. The elderly and the individuals who do not have access to health care, who live in communities where they don't have basic resources in terms of food even are at greater risk and there's a much greater preponderance of these chronic health conditions, the cardiovascular, diabetes, obesity and respiratory, that put them at higher risk both of a climate change related exposure and of a COVID-19. 


Amy Quinton So how is it that climate change puts these populations at risk? 


Helene Margolis Most greenhouse gas emissions are from combustion sources, vehicles, power plants. It's not just greenhouse gases like carbon dioxide. It's also the air pollutants that we already know have adverse effects on health, in terms of our lungs, our cardiovascular systems. And it's not just the acute exposures, it's this chronic exposure. So people who live in highly polluted places have damaged lungs and damaged cardiovascular systems due to those air pollutants. 


Kat Kerlin Let's face it, the neighborhoods next to busy highways and industrial polluters are poor neighborhoods. It's all connected. 


Amy Quinton And so Helene says, if we can ease climate change, we can also ease some of these health conditions. In other words, there are co-benefits. 


Helene Margolis If we address the greenhouse gases and reduce vehicle miles traveled to reduce our reliance on carbon producing fuels. And if we could switch to renewables, we're going to have less air pollution. And I'm talking at the street level where people are exposed. 


Kat Kerlin Did she say how to go about doing that? 


Amy Quinton [She says it starts with making communities healthier and more resilient to climate change. 


Helene Margolis If you create a healthier community where you address these weaknesses or the vulnerabilities, and they're basically called the social determinants of health, where you look at access to care, healthy food, opportunities for physical activity, safe stress-free environments. So overall, creating living conditions that are better. And much of the efforts around the world, but also here in California to address climate change and vulnerabilities, is building sustainable communities that also address health promotion, preventing these basic chronic diseases. 


Amy Quinton Of course, that sounds pretty difficult. 


Kat Kerlin Well, at least we got a break from air pollution and greenhouse gases during those stay at home orders. 


Amy Quinton Right. And we said at the top of this episode that we were going to talk about Fraser Shilling's study that looked at greenhouse gases during the initial phase of the virus. And what he found was all those shelter in place orders went a long way. 


Fraser Shilling So across all the states, the reduction was 60 to 90 percent reduction in driving. Collectively, there was a 71 percent reduction for the whole U.S. in calculated greenhouse gas emissions. It did vary state by state, but it is pretty remarkable that the vast majority of people were following the stay-at-home guidance and not driving. 


Amy Quinton Important to point out, I talked to him in May and the figures were up until mid-April at that point. 


Kat Kerlin But still, vehicle miles traveled dropped from 103 billion miles to 29 billion during the second week of April. 


Fraser Shilling We exceeded our past Paris Climate Accord commitments by at least two-fold. So we met our 2020 goal in eight weeks. 


Amy Quinton But, but, you know, there's a but, it was an eye-opening change, but very short lived, right? Not a permanent change? In fact, when I talked to Fraser the first time in May, some places were starting to open back up and he was already seeing traffic pick back up. 


Fraser Shilling Yesterday, I would have said optimistically, we will retain some of this, right? But today I got the data across quite a few counties across the U.S. there was an almost doubling in driving compared to the four previous weeks. 


Amy Quinton And Kat, more bad news. We now know it's almost returned to normal and almost every state. 


Kat Kerlin Yup. People were itching to get out, most people. Still you have to think some of it will stick. 


Amy Quinton It seems to stick only when there are stay at home orders. But driving less is an important part of reducing greenhouse gases, particularly in this country where transportation accounts for 29 percent of those emissions. 


Kat Kerlin Yeah. And in California, transportation accounts for like 40 percent of our greenhouse gas emissions. 


Amy Quinton Right. But whether I reduced driving was really a success in terms of climate change. Well, that's debatable, right? Millions of people are out of work, which no one wants to see. And really, it shouldn't take a pandemic to get people to drive less. 


Kat Kerlin Some people who used to take public transportation are driving their cars for safety reasons. So now COVID-19 is causing some people to drive more and take mass transit less. 


Amy Quinton Right. It's depressing. So I talked to climate scientist Ben Houlton about all of this. 


Kat Kerlin That's great. Ben is like one of the most optimistic climate scientists I've ever met. 


Amy Quinton Well, he's an affiliate faculty member here at UC Davis and he put our reduction in greenhouse gases due to COVID into some real perspective. 


Ben Houlton If you look at the emissions reductions that are estimated for this year, based on the recent data, we might anticipate an eight percent drop in global emissions largely from transportation. Well, that's an incredible drop, a drop we haven't seen before, perhaps since humans started emitting carbon pollution to the atmosphere. And yet, what does that really look like? Well, the atmospheric concentration of CO2 is about 414 parts per million right now. And that eight percent drop will not even show up as a detectable change in that concentration. 


Kat Kerlin Why do I not find this surprising? 


Amy Quinton Oh, but wait, it gets worse. 


Kat Kerlin There you go again. 


Amy Quinton Not me. Ben Houlton. 


Ben Houlton In fact, estimates are we would need to see at least a 25 percent emission reduction to detect .2 part per million change or a reduction in atmospheric CO2. And ultimately the curve we have to bend is atmospheric CO2. 


Kat Kerlin Yep, I'm depressed. 


Amy Quinton Me too. But wait. He goes on. And you thought I was negative. 


Ben Houlton We can't just cut emissions anymore for decades and expect CO2 concentrations to drop to a level that no longer causes massive human suffering on the planet. 


Amy Quinton Massive human suffering, Kat. He says even if we cut all transportation emissions on the planet, we still have 80 percent, 80 percent of the rest of the worldwide emissions to take care of. 


Ben Houlton People talk a lot about flattening the curve for COVID and then even bending the curve. Well that analogy actually goes back to the climate challenge and what scientists have been talking about for decades of bending the curve, flattening the curve and bending the curve. And we are seeing that collective human action can flatten and bend a curve. 


Kat Kerlin Well, that was short-lived, at least here in the States. But flattening the curve seems to be an even bigger hurdle for climate change. Did he suggest how to do that? 


Amy Quinton Well, I asked him that. 


Ben Houlton We need to grab CO2 from the air. And that's something that humanity has never done before. We have to pull CO2 out. 


Kat Kerlin So in other words, we can't just reduce emissions anymore. It won't be enough. We have to reduce emissions and capture carbon. 


Amy Quinton That means things like restoring forests so that they absorb CO2, carbon farming, which restores soil and natural and agricultural lands. And even using newer technologies that physically capture CO2 and store it underground. The list of ways to capture carbon is long. 


Ben Houlton I actually get excited when I think about the enormity of the challenge now. 


Amy Quinton And that makes Ben very different from me. I get depressed by the challenge. 


Kat Kerlin Well, climate science isn't really where most of us go for our warm fuzzies. 


Amy Quinton I mean, think about it. People clearly are not staying at home, even in counties that are seeing a surge in coronavirus cases, even though thousands of people are dying. Now, we have to convince people that we need to collectively find large-scale solutions to capture carbon, so that maybe we can realize benefits three decades from now. 


Kat Kerlin It is a heavy political lift requiring much more than wearing a mask. 


Amy Quinton Yeah, and speaking of politics, one thing that is perfectly clear during this pandemic is how political it is. 


Kat Kerlin Yeah, some politicians began to question and deny the science, which has happened repeatedly when dealing with the climate change crisis. 


President Donald Trump So supposing we hit somebody with a tremendous whether it's ultraviolet or just very powerful light? 


News Clips Hi, I have a medical condition that I'm not allowed to wear a mask and I'm not required by HIPPA rules and regulations to disclose that. 


News Clips And isn't the herd immunity essential to ultimately getting rid of this virus until at the very least, we get a vaccine? 


News Clips Is the science even settled? 


News Clips There's so much research that says that we actually are in danger of having this mask. I'm breathing my own CO2. Do you understand that? Look at all of these sheep that are here all wearing this mask. It's actually dangerous for them and it's doing nothing for them. A 99 percent survival rate and you're all wearing masks like sheep. 


News Clips Whatever. Details. Shut up. 


News Clips Really, these masks are actually creating even more havoc than than violating the Constitution, but actually causing direct harm of people's lives by incentivizing bullying and harassment. It's terrible. 


News Clips So either wear the mask...I'm not doing it cause I woke up in a free country. 


News Clips I think you'll see by June, a lot of the country should be back to normal and the hope is, is that by July, the country is really rocking again. 


Amy Quinton Here's what Ben had to say about all of that. 


Ben Houlton As somebody who has worked in climate for, well, almost two decades now. I can tell you that what I'm seeing in terms of the politicizing of this epidemic is completely unsurprising to me. I have learned talking to people that you can give them any form of data no matter how strong it is on climate change and if they're in denial, they will basically push that data away with no problem. And it's a form of denial that is as deadly as other forms of denial. And I think we're seeing that right now. And when it comes from the top down, it's even more difficult to deal with. 


Amy Quinton Epidemiologists, on the other hand, were caught off guard. I asked Tracy Goldstein what she thought about some of the science denial. 


Tracy Goldstein I have been really surprised by that because I feel like this is a public health emergency. This is the time for the world to unite and support each other and have the best information that we can together to answer a question and a problem vs. making it into some sort of political thing that I just I don't understand. I feel like this is a time for unity, not separation. 


Kat Kerlin So did Ben have words of advice for epidemiologists or any theory as to why this happens? 


Amy Quinton Yeah, he explained the reasons science denial happens during the pandemic is the same reason it happens when dealing with climate change. 


Ben Houlton When special interests in large conglomerates stand to lose money by the solutions, misinformation and disinformation are very soon to be spread. And we're seeing the same thing with COVID-19. If it hadn't caused a radical reduction in our economy, our economic output, in approximately 30 million people maybe going unemployed, I don't think we'd be seeing the same level of science denial that we're seeing. 


Amy Quinton But here's the thing: to deny a problem exists doesn't make it go away. And I think we have a huge lesson to learn from how we've handled this pandemic, especially as it relates to how we handle the climate crisis going forward. And Ben agreed with me. 


Ben Houlton If you don't prepare in advance the impacts on the economy, on people on the planet are magnified in the future. And in climate, it's something on the order of an estimated $20 trillion of economic damages as we start to experience dangerous climate interference in the future. That can be avoided if we start investing today. 


Kat Kerlin Yeah, in the climate science world, people talk about mitigation, which is preventing it, and adaptation preparing to deal with the changes that come. And I, I think there's some similarities with that and the pandemic. So maybe a lesson is to spend more money on preparing for a pandemic and also have a better national stockpile of masks and protective gear and ventilators or also some more funding to detect emerging diseases. 


Amy Quinton And more mass testing. You know, epidemiologists, as you know, Kat, have always warned of a coming pandemic. They knew this day would come. And in the same way, we know there will be huge economic losses from coming climate disasters. So the time to prepare is now. 


Kat Kerlin  And the poor, people of color, the elderly, the disadvantaged, they will be affected the most. So we can work on those disparities. There is one huge difference, though, between the climate crisis and the COVID crisis. 


Amy Quinton Yeah, what's that? 


Kat Kerlin Well, eventually we will have a vaccine for COVID-19. There is no vaccine or silver bullet solution for climate change.

Amy Quinton Well, there's not a silver bullet but Ben and many experts who are going to hear from during this season of Unfold are going to talk about the many ways to become more resilient in the face of climate change.

Kat Kerlin You can find out more about UC Davis climate change research by visiting our Unfold website at or our Science and Climate website at

Amy Quinton I'm Amy Quinton.

Kat Kerlin And I'm Kat Kerlin. Thanks for listening.

Credits Unfold is a production of UC Davis. It's produced by Cody Drabble. Original music for Unfold comes from UC Davis alumnus Damian Verrett and Curtis Jerome Haynes.

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