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Risk if infectious disease increases as climate change becomes more impactful. 

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Risk if infectious disease increases as climate change becomes more impactful. 

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Diseases such as Lyme disease, West Nile Virus disease, and Valley fever are on rise due to mild winters, warm summers, and fewer days of frost. Mosquitoes and ticks have more time to reproduce as winters are more mild, spring starts earlier, and temperatures are warmer. Rising temperature forces animals to move into new habitats, creating the spread of zoonotic diseases because humans and animals live closer together. Valley fever, which is caused by fungus living in hot and dry areas, has spread into the Pacific Northwest and is treated incorrectly due to misdiagnosing. As humans eat food that comes from water, harmful algae blooms in the water can cause sickness or even death after a couple of days with contact.

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Download the full version of this page [PDF - 4 pages]
Our Risk For Infectious Diseases Is Increasing Because of Climate Change
As the nation's public health leader, the Centers for Disease Control and Prevention (CDC) is actively engaged in a national effort to protect the public's health from the harmful effects of climate change. Scientists from CDC's National Center for Emerging and Zoonotic Infectious Diseases (NCEZID) are at the forefront of many of these efforts. This report highlights some of that work and also looks ahead to the important work yet to come.
Lyme disease, West Nile virus disease, and Valley fever. These are just some of the infectious diseases that are on the rise and spreading to new areas of the United States. Milder winters, warmer summers, and fewer days of frost make it easier for these and other infectious diseases to expand into new geographic areas and infect more people. To understand climate change's impact, it's important to look at some of the common ways these diseases spread-through mosquito and tick bites, contact with animals, fungi, and water.

As the climate changes, the risk also increases for health threats such as:

Anaplasmosis

Anthrax

Antibiotic-resistant infections

Cryptosporidiosis

Dengue

Ehrlichiosis

Fungal diseases like valley fever and histoplasmosis

Giardiasis

Hantavirus

Harmful algal bloom-associated illness

Lyme disease

Plague

Rabies

Spotted fever rickettsiosis

Salmonellosis

Vibriosis

West Nile virus disease

Mosquitoes and Tick Bites

Mild winters, early springs, and warmer temperatures are giving mosquitoes and ticks more time to reproduce, spread diseases, and expand their habitats throughout the United States. Between 2004 and 2018, the number of reported illnesses from mosquito, tick, and flea bites more than doubled, with more than 760,000 cases reported in the United States. Nine new germs spread by mosquitoes and ticks were discovered or introduced into the United States during this period. The geographic ranges where ticks spread Lyme disease, anaplasmosis, ehrlichiosis, and spotted fever rickettsiosis have expanded, and experts predict that tickborne diseases will continue to increase and perhaps worsen. Longer, warmer summers have also given mosquitoes more time to reproduce and spread diseases. In 2012, a mild winter, early spring, and hot summer set the stage for an outbreak of West Nile virus disease in the United States, resulting in more than 5,600 illnesses and 286 deaths.

Contact With Animals

Climate change has forced some animal species into new habitats as their natural habitats disappear, and it has expanded the habitats of other animals. This movement of animals into new areas increases opportunities for contact between humans and animals and the potential spread of zoonotic diseases, as these examples show:

Wildlife carrying the rabies virus are expanding to new geographic areas of the country.

Arctic temperatures are rising more than twice as rapidly as the rest of the world. Warming temperatures in Alaska have led to increases in vole populations, which can spread diseases like Alaskapox to humans.

As global temperatures rise, deadly diseases that are a threat in other countries - like Ebola, Lassa, Rift Valley fever, and monkeypox - will increase along with the risk of them being imported into the United States.

Fungi

Rising temperatures have allowed certain disease-causing fungi to spread into new areas that previously were too cold for them to survive. For example, Valley fever - caused by a fungus that lives in the soil in hot and dry areas - has already spread into the Pacific Northwest. This fungus can cause severe infections and death and is often misdiagnosed and treated inappropriately. As the difference between environmental temperatures and human body temperatures narrows, new fungal diseases may emerge as fungi become more adapted to surviving in humans. Climate change also increases the risk for natural disasters and flooding, which can increase the risk for mold to grow in people's homes. Certain molds can cause deadly infections of the lungs and brain.

Water

Scientists predict that climate change will have devastating effects on freshwater and marine environments. For example, we could see more frequent and more severe instances of harmful algal blooms, which are the rapid growth of algae or cyanobacteria in lakes, rivers, oceans, and bays. Warming temperatures in Lake Erie have contributed to extensive toxic blooms that last into the early winter months. Harmful algal blooms can look like foam, scum, paint, or mats on the surface of water and can be different colors. They endanger our health when we eat contaminated shellfish. They also can harm pets, livestock, wildlife, and the environment. While no human deaths caused by cyanobacteria have been reported in the United States, some of these toxins can make dogs and other animals sick and possibly even cause death within hours to days. Dog deaths have been reported after dogs swam in or drank fresh water containing cyanobacterial toxins.

Additionally, scientific evidence shows that traces of antibiotics are present and can sometimes remain in the environment (waterways and soils) for a long time. Scientists need to do more research to better understand the connection between the environment, existing and emerging antibiotic resistance and its spread, and the impact on human health.

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Download the full version of this page [PDF - 4 pages] As the nation's public health leader, the Centers for Disease Control and Prevention (CDC) is actively engaged in a national effort to protect the public's health from the harmful effects of climate change.

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Climate change, urbanization, and humans spreading into new areas changes the ranges of insect-borne diseases. The climate changing also forces humans and animals to be in closer contact, forcing each to be closer with pathogens that cause disease. All the travel that humans do and how interconnected the entire world is means that diseases spread far more easily than it used to. As the heating of the Earth disrupts the weather, such the creation of monsoons, malaria outbreaks cost more. There is still so much unknown about the relation between climate change and infectious diseases, but many people are are unwilling to change that due to skepticism.

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How climate change and health are connected.

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How climate change and health are connected.

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This podcasts discusses how diseases are related to the temperature rising. The way that pathogens rely on temperature means that it effects whether or not the disease will spread. As the Earth continues to increase in temperature, the more likely it is for the diseases to occur, especially in places that are not adaptable. Diseases are not able to be stopped by physical boundaries; they must be stopped through stopping climate change. The speakers in the podcast argue that if we are so quick to fix infection and put money to stop diseases, the same should occur to climate change because increasing heat could cause more infection.

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See transcript

Noah Leavitt: Coming up on Harvard Chan, This Week in Health, Climate Change and Our Health.

Ari Bernstein: When you change the climate, you sort of change the rules of the game for human civilization.

Noah Leavitt: In this week's episode, an in-depth conversation about the effects of climate change and the steps we can take to reduce the damage.

Noah Leavitt: Hello and welcome to Harvard Chan This Week in Health. It's Thursday, February 16, 2017 I'm Noah Leavitt.

Amie Montemurro: And I'm Amie Montemurro. In this week's episode, we'll be sharing an in-depth conversation on the health effects of climate change.

Noah Leavitt: And this will be the first in a multi-part series looking at links between climate change and health. I recently sat down with Ari Bernstein, who is Associate Director of the Center for Health in the Global Environment at the Harvard Chan School, and also a pediatrician at Boston Children's Hospital. In this week's episode, we speak about what we know about the health effects of climate change and what can be done to mitigate those effects.

Amie Montemurro: And in the second half of our conversation, which you'll hear next week, we spoke specifically about communicating about climate change and strategies to reach those maybe skeptical about the effects. In future episodes will be looking specifically at how climate change may affect our food supply and even mental health. But for now, here's part one of our conversation with Ari Bernstein.

Noah Leavitt: You're a pediatrician, but also you work over at the Center for Health and the Global Environment. So can you talk about kind of how you kind of came into environmental health, studying the effects of climate change?

Ari Bernstein: I was exposed to climate change as a scientific problem relatively early on. And it was compelling because people were saying that by changing the composition of the atmosphere we were going to change the climate. And when I went to medical school, I was thinking that this has got to matter to people's health. At that time relative few relatively few people were engaged. But it was apparent then as it is now, that climate change has vast implications for our ability to lead healthy lives.

And as a pediatrician, you know, our job is essentially to keep kids healthy and mostly to prevent kids from getting sick. So there is really a natural pairing between being a pediatrician and thinking about climate change. In the same way that you know I give kids vaccines to prevent disease, I would like to prevent our kids from experiencing the ills of climate change. And those are preventable in many cases.

Noah Leavitt: And so you just touched on something there, the ills of climate change. So what do we know now about what some of the health effects of climate change are?

Ari Bernstein: We know enough to know that reducing greenhouse gas emissions is the most cost-effective strategy to prevent health outcomes that we don't want. And the way I think about the health effects of climate change is that they really affect all of the great progress we have made in dealing with nutritional problems, infectious problems, in some cases mental health. And that's because when you change the climate, you sort of change the rules of a game for human civilization.

So you know, we've only grown food for ourselves for about 10,000 years. That's occurred because the climate of the Earth is where it is now. And we're pushing ourselves out of the envelope. So we're changing the game for how we grow food. Carbon dioxide is, as Sam Myers and others research here at the school has shown, carbon dioxide itself affects nutritional content of plants.

We change the way infectious diseases work. There is no pathogen that isn't in some ways temperature sensitive, and especially vector borne diseases. There's the prospect that climate change will destabilize where are those infections can happen. There's a lot of other things can affect where infections do and do not happen. There used to be malaria in Washington, DC. There isn't anymore. That's not because the climate has done anything but warm since it was eradicated there. But nonetheless, particularly in places in the world where they are least able to adapt.

The other thing, of course, is sea level rise. You know, lots of people live near the coast. People are moving to the coast. At the same time sea level's rising. And one of the areas in which climate science has been particularly clear is on the accelerating rate of sea level rise as we learn more about the melting of ice sheets in Greenland and Antarctica. So really across the board climate change has effects upon health.

But again, it's quite clear that if we want to do a really powerful thing when it comes to protecting and improving people's health, we would do well to reduce our use of fossil fuels, to increase our rates of active transport, bicycling, walking, so forth, and really get a win-win in a sense. We get short term benefits from air pollution. We get long term benefits from greenhouse gas emissions.

Noah Leavitt: And so just to jump off of that, you give this interview with Harvard Public Health Magazine, and I believe the quote was, "reducing greenhouse gases in the Earth's atmosphere may be the greatest public health intervention ever." You just touched on it there. You mentioned how it's cost-effective. So can you explain a little bit more about why focusing on reducing greenhouse gas emissions is such an effective public health intervention?

Ari Bernstein: A lot of the health outcomes are clear in the sense that we can anticipate they will happen, but their magnitude is really hard to know. And infectious disease burdens, vector-borne disease is a good example of that, even to a certain extent nutritional outcomes, if we're having a harder time growing food because there are droughts or heat waves. We can see those things happening. We're not entirely sure how that's going to lead into nutritional outcomes. But if you're a gambling person, you're probably not going to bet that climate change is going to be good for either the spread of vector-borne diseases or nutritional outcomes or a host of other things.

And so, then you get into this math about, is it cost effective to do something now? And one of the big arguments that stands out about whether we should be doing more to reduce our greenhouse gas emissions is that it's not cost-effective. It's going to cost too much. Well, that's an accounting problem. And we're stumbling on an economic model that essentially says, we can only count what we have counted, and if we can't count it it, doesn't really matter.

And you know, I get that but it also is essentially pitting the present moment against the future. And as a physician, what we're doing makes no sense, because if I saw a child come to see me at Children's who was say, two weeks old and had a fever and you know had been exposed to, as many kids this time of year are, lots of people with colds, I don't presume that that child has a cold, and won't get better with medication.

We know from experience. We have some reason to believe that there's a very small percentage of kids who will have a potentially life-threatening infection. And so, we act in the likelihood that that will be reality. We do everything we can to find that infection, and we treat with antibiotics presumptively before we know the infection is there. If it turns out, in a couple of days that there's no sign of infection, we stop the antibiotics, the kid goes home.

Well, that's sort of the analogy here, which is that we don't know for sure how severe the health consequences are going to be. We have ample reason to be concerned and we have technologies that can substantially move us off fossil fuels rapidly. And we're not using them as much as we might because people are saying it's not cost-effective in this limited sense of cost-effectiveness.

So you know, this issue of the greatest public health intervention ever, you know if sea levels rise by as much as 10 feet, we're talking about tens of millions of people are going to be displaced. Those people, if you find people who have been forced to move against their home- forced against their will to move from their homes, they have some of the worse health status in the world. Think about people displaced by Katrina or the Syrian refugees across the board. So that population of itself would be an enormous issue.

But then you think about the nutritional piece. So we had a massive heat wave in Europe a few years ago. It burned about a quarter of the Russian wheat crop. Russia stopped exporting food, and there were global price spikes in food, and that caused food riots in Mozambique and people's ability to get access to food. Because a lot of the poorest countries in the world are net food importers. They don't grow enough to feed their own populations.

You think about heatwaves and the predictions around heatwaves, and on and on and on and on. So you know again, I think one of the stumbling blocks here is that there are a lot of people who feel that we don't have enough certainty to do more or that the economic equations don't pan out enough. On the first issue, I would say we know well more than enough to be doing more in reducing our greenhouse gas emissions, even from a health standpoint. Forget about the economic arguments, by the way, which are also significant or the national security arguments, which are also profound.

And on the math thing, you know, even the economists they use this thing called the discount rates, which is essentially how much you value money in the future, whether or not this is cost effective even with the limited understanding of the health costs that we have, like the ones we can actually put numbers on, even with that, it's simply a matter of what discount rate you choose and how much you think the future is worth compared to the present. And there are vast arguments over that.

But to me it's- you know, to play devil's advocate, the argument is that if we spend too much now to move away from fossil fuels, it could be damaging to our economies in the present. I think that that's a rational argument but it belies the reality that you would be hard pressed to think about a more cost effective time, even with technologies becoming less expensive, because of the long atmospheric half life of carbon dioxide. This stuff is going to be around for a very long time.

And even if we went cold turkey on carbon emissions today, there would still be increases in CO2 through the century that would cost-effect. So again, we have a hard time doing accounting here. As a physician, I look at the situation and say, I would never treat a patient this way. No one as an individual would accept being treated this way. They would never say there's a potentially small but real probability of civilization being undermined, and us saying well, it's a little too expensive right now to do anything.

No one would say you know it's a little too expensive to have your appendectomy right now. Let's wait a little while and see if that's a good idea. So that's sort of what we're doing here. Some of us, some people are thinking in this realm and it just doesn't make sense when you really scratch below the surface.

Noah Leavitt: Are there any kind of big unanswered questions when it comes to climate change and health or is it more a situation where we know what the health effects are, the unanswered question is how severe they will be or when we'll start to see these effects?

Ari Bernstein: So there's two sides to that coin. We can always try and learn more about the specific health outcomes. That's going to be really hard. , And again in this analogy with the baby who comes in with a fever, you know, it's going to be hard for us to make precise estimates of health outcomes, aside from maybe heat and potentially sea level rise. A lot of these things are hard to model in ways that you can get clear answers.

But I do think in the debate about cost-effectiveness and policy, we can do much more to understand the health benefits in the near term from things that reduce greenhouse gas emissions. So we've done a little bit around air quality. Some of the research has come out of the school, Jonathan Buonocore and Joel Schwartz in particular have been involved, looking at how many lives would be saved if the Clean Power Rule that was set forth in the Obama Administration were implemented, it's thousands of lives a year in the United States.

But you know, we haven't even touched things like food waste. So we throw away a quarter, potentially more, of the calories produced. Those calories all have greenhouse gas embedded in them, but they also have water. They also have fertilizer that runs off into our rivers and pollutes waterways. And there's all the equipment that's putting out fossil fuel-based pollution. So there are a whole suite of co-benefits there from water consumption and scarcity to fresh water pollution to air pollution, and potentially even to caloric insecurity. So in place of the world where calories are really scarce, if we're still wasting lots of food, know if we reduce that there will be benefits to nutrition.

If we got a better handle on those things and could put monetary values on them, then they can be put into these contexts, is it cost-effective to reduce carbon dioxide emissions? But without any of that quantified, it becomes hard to do that. So we've got food waste as an issue. We've got active transport. We've got dietary changes. We've got a whole host of these so-called co-benefits, which if we were better able to get a number on the benefits, those, benefits we could include them in conversations about whether we should be doing more right now. And I think that is one of the biggest areas we need research in right now.

Noah Leavitt: That was part one of our conversation with Ari Bernstein on the health effects of climate change. Coming up next week, how can we communicate more effectively about climate change?

Ari Bernstein: This is a view of the world in which we live for tomorrow, but not for our children.

Noah Leavitt: How did climate change become such a polarizing topic? What can be done to change that? And why empathy might be the key to shifting the conversation.

Amie Montemurro: If you're interested in learning more about climate change and its effects, we have a page of resources for you. You'll find a link on our website, hsph.me/thisweekinhealth.

Noah Leavitt: And that's all for this week's episode. I'm Noah Leavitt.

Amie Montemurro: And I'm Amie Montemurro. A reminder, you can always find the podcast on iTunes, SoundCloud, or Stitcher.

See transcript

Amie Montemurro: Coming up on Harvard Chan This Week in Health, part two of our series on climate change and health.

Ari Bernstein: This is a view of the world in which we live for tomorrow, but not for our children.

Amie Montemurro: In this episode, communicating about climate change. How did climate change become such a polarizing topic? What can be done to change that? And why empathy might be the key to shifting the conversation.

Amie Montemurro: Hello, and welcome to Harvard Chan This Week in Health. It's Thursday, February 23, 2017. I'm Amie Montemurro.

Noah Leavitt: And I'm Noah Leavitt. In this episode, we're bringing you part two of our conversation with Ari Bernstein, a pediatrician and associate director of the Center for Health in the Global Environment at the Harvard Chan School.

Amie Montemurro: In part one, which aired last week, Bernstein explained what we know about the health effects of climate change and some potential strategies to reduce or reverse the damage.

Noah Leavitt: If you haven't listened to part one, we'd obviously encourage you to go back and check it out, but if you did miss it, we'll be playing a short clip from that interview where Bernstein gives an overview of links between climate change and health. After that, we'll jump directly into our conversation about communication and climate change. And so here's Bernstein now explaining what we do know about health effects of climate change.

Ari Bernstein: We know enough to know that reducing greenhouse gas emissions is the most cost effective strategy to prevent health outcomes that we don't want. And the way I think about the health effects of climate change is that they really affect all of the great progress we have made in dealing with nutritional problems, infectious problems, in some cases mental health, and that's because when you change the climate you sort of change the rules of the game for human civilization.

So we've only grown food for ourselves for about 10,000 years. That's occurred because the climate of the Earth is where it is now, and we're pushing ourselves out of that envelope. So we're changing the game for how we grow food. Carbon dioxide is, as Sam Myers and others' research here at the school has shown, carbon dioxide itself affects nutritional content of plants. We change the way infectious diseases work. There is no pathogen that isn't in some ways temperature sensitive, and especially vector borne diseases. There's the prospect that climate change will destabilize where those infections can happen.

Now, there's a lot of other things that can affect where infections do and do not happen. There used to be malaria in Washington, DC. There isn't anymore. That's not because the climate has done anything but warm since it was eradicated there, but nonetheless, particularly in places of the world where they're least able to adapt.

The other thing, of course, is sea level rise. Lots of people live near the coast. People are moving to the coast. At the same time, sea levels rising, and one of the areas in which climate science has been particularly clear is on the accelerating rate of sea level rise as we learn more about the melting of ice sheets in Greenland and Antarctica. So really across the board climate change has effects upon health, but again, it's quite clear that if we want to do a really powerful thing when it comes to protecting and improving people's health we would do well to reduce our use of fossil fuels, to increase our rates of active transport- bicycling, walking, so forth- and really get a win-win in a sense. We get short term benefits from air pollution. We get long term benefits from greenhouse gas emissions.

Noah Leavitt: In some ways, is it easier- when you're communicating about it, do you focus on these are the benefits if we make changes versus these are the negative effects if we don't make any changes?

Ari Bernstein: Yeah, no question that it's better to focus on the benefits. It's kind of hard to articulate a motivating message that says climate change is bad in a big way. We can't exactly tell you how big and how bad when or where. I mean- which is a significant part of that reality right now. I mean, again, with heat or sea level rise there's a little more clarity there.

In any event, people are much more inclined or much more likely to be motivated by a reward in the near term. And even though I think there are compelling, for example, intergenerational arguments- like if you're a grandparent saying, do you want to leave the world a better place for your grandchildren? And there are compelling longer term messages. There's no question that if you can say to someone that by eating less red meat you're less likely to die of colon cancer, and, oh by the way, will reduce all kinds of other things we don't want to admit, like greenhouse gases, air pollution, so forth that come with red meat production. People are potentially more inclined to act. So yes, there has to be, I think, a much clearer articulation of how actions that reduce greenhouse gas emissions have direct benefits to people in the near term.

Noah Leavitt: And so kind of jumping off of that, I mean, I think you kind of touched on kind of I guess what needs to be done, but looking for scientists or public health professionals, what have they done well when communing about climate change? But I guess and then the flip side of that is, what are some areas that maybe need some more work or more focus?

Ari Bernstein: I've spent a fair amount of time thinking about how we got to where we got in terms of the relative inaction on climate change. It's important to acknowledge that the Paris Accord is a watershed event.

Noah Leavitt: And a quick interjection here- for people who may not be familiar, Bernstein is referring to the 2016 Paris agreement. The accord was signed by 194 countries and laid out a framework for reducing greenhouse gases and mitigating the effects of climate change. It also aims to limit the rising global temperatures to less than two degrees Celsius. And now we'll head back to our conversation with Ari Bernstein.

Ari Bernstein: This is essentially every country in the world is coming together in a peaceful way and making an agreement to do something about a problem that we can only solve together, which I think for our species is a wonderful, wonderful achievement. Nonetheless, clearly we're not doing enough by anyone's estimation. How did we get here? Why is it that, on the one hand, the scientific community seems so clear that this is a relatively well understood problem with severe consequences for humanity and yet we don't seem to be able to pull the trigger on doing what we need to do?

The way that climate change largely entered policy discourse was through the IPCC, the intergovernmental Panel on Climate Change. This is a UN framework that was started in the Rio Earth Summit 1992, and that idea of the IPCC was to provide the scientific evidence that described climate change to policymakers, and that by doing so, they would be empowered to act in a responsible way. Well, that didn't work at all, and it didn't work for a number of reasons.

It turned out that there were real discrepancies in understanding about who was responsible, so going back to the first Bush administration, there was a carbon tax proposed, which got destroyed in the Senate. I think it was voted down in 98 to 2, or maybe it was 98 to 0. I don't remember. It was a landslide. And one of the arguments then was, why should we do something about this when China is going to be the major polluter? What's their responsibility?

So you got these disagreements between countries about who is responsible. Rich nations, poor nations, north south- there became this very sticky diplomatic problem with all kinds of responsibilities, be it who is emitting now, who was emitting in the past, how much should we get for our trees? That's cluster carbon. All this stuff became problematic.

Then there were concerted efforts on the part of specific interest to undermine climate science. These came from corporations. They came from individuals, and these were underhanded and unethical things. These were not intended in any way in people's best interest, and for those who have followed this, there are now lawsuits against corporations claiming just as with big tobacco that they hid information and purposefully misled the public and scientists about this issue. But those are real, and they're profound, but I think one of the biggest challenges- and this gets to the part of the question of what could we be doing differently- is that it turns out that aside from those issues we are dependent on fossil fuels.

I mean, there's nothing we can do that doesn't require fossil fuels right now, and that includes for people like me. I use electricity. I eat food- but particularly for the people whose livelihoods depend on it, whether they are working directly in the fossil fuel industry, whether they work in the plastics industry. They use fossil- on, and on, and on our economy is saturated with fossil fuels. And I think that provided fertile ground for doubt to be sewn.

And people on one level didn't want to believe that what they were engaged in could potentially be catastrophic. I mean, I don't want to think that my day to day existence as an American is contributing disproportionately to this problem, but the truth is that it is. I don't want to look at that reality, but it's true, and so this IPCC model where we present the data was worked for things like the Montreal Accords, which dealt with the chemicals that deplete the ozone layer, which protects us from ultraviolet radiation. It worked in the Clean Air Act. The science was incredibly influential there, even though there was a lot of push back there.

And I think the embeddedness of fossil fuels in our society has really made it much harder. The other side of it is that it became- sometime in the early 90s and progressively since it became less about the science and more about tribal affiliation, and that was, I think, a concerted tactic on the part of those who didn't want to do something about it to make it less about what science said and more about if you are a- if you believe in certain other political views, you also must be against doing something about climate change and vice versa.

And so the conversation moved away from evidence and science into a you're a bad person if you think this, and that made it yet harder. At the same time- and we're seeing this in the United States right now- is that there's this enormous empathy gap. So we had on the side of doing something about climate change this attitude that people who were not willing to do that were bad and vice versa- that people who were advancing an agenda to deal with climate change were killing jobs and really didn't understand. And that's something that we can do better with. We need to be much more compassionate and empathic about what it would mean to large numbers of people in the United States and elsewhere should we not use fossil fuels.

We can't just say we're going to go from A to B as if people didn't have livelihoods. So I think in the communications front we could learn a lot from our colleagues at the business school about marketing and how to make our understanding of this problem compelling in the frameworks that people hear, be it religious, ethical, health, economic, national security. And there's some of that, but we really can do much more.

Noah Leavitt: And so I think you touched on something important there, and I think this has kind of been in the news lately, but this idea that science itself is kind of becoming politicized. And so I think you just touched on it there, but what can be done to combat that? And I guess in the context of- for people who might be kind of doubting the health effects of climate change, what can public health professionals do to kind of combat that where science is politicized, where kind of there's doubt about the effects of climate change?

Ari Bernstein: Yeah, it's a great question and extremely timely. This is where history is really important. There was a period of time not so long ago- most Americans may not know this- where medicine as a practice was highly unscientific. Highly unscientific. It was essentially no different than the dark ages when there were apprenticeships, and people sort of learned by learning what their mentor had learned. And that was based upon experience, and our experience is important, but I can tell you that if we treated patients based upon individual clinician's experience there'd be a lot of unnecessary suffering in the world.

And it becomes very easy for people to not grasp, for example, how scientific research has dramatically reduced rates of death from heart disease, how it's dramatically reduced rates of death from cancer, how it's dramatically increased longevity in the United States. All these things depend upon the scientific method, but for people who don't have a scientific background and are fearful of science because it's so abstract and so foreign, it becomes just another point of view. It becomes like a different religion, and that's tricky because if scientists then come out and say we're not another religion and here's why, it sounds like we're advocating for our tribe. It sounds like we're really doing what any other group would do.

So I think there are a couple of things that need to be done. One is I think clinicians- physicians in particular- need to be much more vocal, because we sit at this critical interface between science and applied science, where we have to in some cases do science, but we're always applying science- or as best we can. And we see people, and we deal with people at a very personal level.

And if you look at surveys about who people trust in the United States, it's number one- it's nurses, and number two it's doctors. And so I would include nurses very much in this idea, but there needs to be the articulation of, you know, I'm treating you with these antibiotics, and these antibiotics exist because of scientific research. This isn't about your belief, or my belief, or whatever. This is about a process that we've used to substantially improve health. And that's the same kind of science and research that we're using when we think about climate change.

Now, there's a fair amount of the public I would say- and skeptics- who are at that level of complexity, where science is just another dogma, and it really is no different than anybody else, in my view. The slightly more sophisticated arguments come into, well, yeah, I think climate change is a problem, and humans are causing it, but it's not OK- we're not clear that it's the right thing to do right now- to do something about it. And that gets back to the point I made before, which is that this is a view of the world in which we live for tomorrow, but not for our children.

And there's no question that, although we've incurred enormous expense already from climate change related events, the damages are going to accelerate, and so for the moment, for the day, if you wanted to maximize your profitability as a corporation, if you wanted to essentially maintain the status quo in which fossil fuels are heavily embedded in our country, there's no question that doing nothing is a pretty good thing to do, but again, that is very shortsighted. And again, I think I would call upon people who are at the interface between science and the public.

These are journalists. These are physicians. These are meteorologists- and call upon them to say we can't think about these things in the immediate term alone and that there are many angles that one can make that case. This gets back to the messaging, be it energy independence, be it national security, be it economies. I mean, I can't tell you how many companies we've spoken to who are begging for a carbon rule because they know that climate change is going to destroy their business, and yet they are not empowered to act in their own best self-interest because if they did so without a carbon tax it's cost ineffective. And if I ran a business, I would make the same decision.

So we really do need- we do need a change in outlook about how to make science more relevant to the public. It's a tall order because scientific literacy in the United States is not robust, and I think we need to be careful about scientists going out and doing that, because there's the prospect that that could backfire, and I do think it is incumbent upon- at least from the health sector. We've seen this in the national security sector. We've seen the military leaders. You've seen religious leaders. And I think to a certain extent health is a powerful motivator because there's a large segment of the population that will resonate with the health dimensions of this, where they may not resonate with others.

Noah Leavitt: Before we wrapped up our interview, Bernstein wanted to hone in on two key points that he hopes all of you will keep in mind when thinking about climate change.

Ari Bernstein: There will be no time in the future in which it will be more cost effective to move away from fossil fuels than the present. Now people argue about how quickly, but no one would argue that we're moving anywhere- we're not pushing the envelope on going too quick right now by any estimation. The second is that we don't have a scientific problem on our hands. What we have is a cultural shift in some ways and a problem that exists because of our own brains. We have to sort of defeat our own hard wiring because our brains predispose us to bias towards what benefits us immediately in the near term versus the long term.

And that really requires thinking about the near term benefits, as we talked about, these co-benefits. And it also requires greater empathy, and I can't underscore that enough. I think that we, on all sides, have not done- for those of us who are earnest and honest about this, which is the vast majority of people here who really do have interest in doing the best thing, we don't understand each other as well as we might. And I think in that absence we have arguments about different things. We have arguments about- are we talking about government takeover of individual responsibility versus the common good?

It's not the argument we need to have. We need to have the argument about which of the renewable energy sources makes most sense to deploy as quickly as possible here, there, and anywhere. How do we get- how do we strengthen rules that exist like [? Reggie ?] in New England or the California rule on carbon emissions? How do we show their benefits and make it clear that this is actually a good thing to do for the economy? I should mention that renewable energy jobs surpassed, I think, oil and gas in the United States last year. So there's data here, but I also think that the empathy gap exists, and it needs to be filled for us to make progress.

Noah Leavitt: That was our interview with Ari Bernstein talking about communicating about climate change. Again, if you did miss part one, you can find the link to it on our web site, hsph.me/thisweekinhealth.

Amie Montemurro: And as we mentioned last week, these are the first two episodes in our re-occurring series on climate change and health. Coming up in future episodes, the key ways in which climate change will affect our food supply, plus a look at the potential impact on mental health.

Noah Leavitt: That's all for this week's episode. I'm Noah Leavitt.

Amie Montemurro: And I'm Amie Montemurro. As a reminder, you can always find this podcast on iTunes, SoundCloud, or Stitcher.

See transcript

Noah Leavitt: Coming up on Harvard Chan This Week in Health, part three of our series on climate change.

Sam Myers: We need to essentially increase food production by about 70% over the next 40 years in order to keep up with demand.

Noah Leavitt: In this episode, we examine how changes to our environment will not only affect what we can grow, but will make the food we're already growing less nutritious.

Noah Leavitt: Hello, and welcome to Harvard Chan this week in health. It's Thursday, March 2nd 2017. I'm Noah Leavitt, Amie Montemurro is off this week. This is part three of our series on climate change and health. In parts one and two, Ari Bernstein gave us a broad overview of links between environmental changes and our health. It also shared strategies for communicating more effectively about climate change. If you're listening to us on our website, you'll find links to both episodes. In the next two episodes we'll be taking deeper dives into two specific areas, food and mental health.

A recent daylong conference in Atlanta explored the wide ranging health effects of climate change. The climate and health meeting was organized by a coalition, including the Harvard Global Health Institute, former vice president Al Gore, and the American Public Health Association. It came together after the Centers for Disease Control cancelled the previously scheduled three day conference shortly before the inauguration of President Donald Trump.

In a few minutes we'll hear a presentation from Sam Meyers, senior research scientist in the Department of Environmental Health here at the Harvard Chan School. But first to set the stage, we wanted to share some remarks from Ashish Jha He's director of the Harvard Global Health Institute and K.T. Li professor of health policy at the Harvard Chan School. Jha explained why we can't wait to take action to address climate change.

Ashish Jha: One hundred years ago a child born on this planet had a 1 in 3 chance of dying before the age of 5. That number has been cut by 90%. That is remarkable progress. And much of that gain has come from better nutrition, more plentiful food, better crops. But here's the problem, as the world warms and as hot places get hotter and dry places get drier we will see more droughts, we will see more famines. The nutritional content of food will change and the children and families who are thriving now will face hunger, they will face malnutrition, they will face diseases, and they will face death. And as the weather becomes more extreme, the pollution that is all around us, it's going to become deadlier. We will see more cases of asthma, and heart disease, and stroke.

And as the climate changes, so will the infectious diseases that we confront. More outbreaks like Ebola and Zika, more pandemics like the bird flu. And here's the catch, walls will not keep these pathogens out. No borders are going to protect us. That's what awaits us unless we act. We must commit to funding and supporting research on climate change and its impact on health. And I believe that's how we become smarter about protecting the American people, and that's how we begin to share knowledge to protect people around the globe. Universities create and share knowledge, that's what we do. And through that knowledge we educate not just our students but the broader public. And here, I think we as universities need to do a much, much better job helping our citizens and our policymakers understand what's at stake and what must be done.

Health is the human face of climate change. That's what Michelle Williams, the dean of our School of Public Health, likes to say. And she's right. This is not just about temperature rises and sea level changes, though those are important, it's about fighting hunger and starvation, it's about preventing that child's asthma attack, it's about stopping the spread of diseases. Ultimately, it's about creating a world where children don't just make it to the age of five, they grow up to be adults who are thriving, and healthy, and productive. That's the world we want.

And universities like mine and others recognize that's the threat we face. That's the world we need to have that is threatened by climate change. And we want and we need to be part of the solution. To meet the public health challenge that is climate change. To produce unbiased data driven research and making it both accessible and actionable. To train the next generation so they understand the science of climate change and its impact on health. And to educating the American public and American policymakers, really global policymakers, so they too understand the effects of climate change and the costs of action.

Noah Leavitt: That was Ashish Jha on the urgent need to take action to address climate change and mitigate its health effects. Now, let me share a presentation from Sam Myers of the Harvard Chan School. Myers has extensively research how environmental changes will affect the global food supply, and over the next 10 minutes I'll learn how climate change will not just affect the types of food we can grow and where we grow it, but how that food will actually become less nutritious over time. Take a listen.

Sam Myers: We find ourselves at a really, really interesting moment when global demand for food is rising more steeply than ever before in human history at the very same time that our own activities are fundamentally transforming the biological and physical conditions that underpin just about every aspect of our global food production system. Failures of nutrition drive more disability and death around the world than any other risk factor, and climate change is threatening the quantities of food we can produce, it's quality, and even the locations where our food is produced. Early studies from the 1990s suggested that there might be a silver lining, that increasing carbon dioxide in the atmosphere might have a fertilizing effect and increase crop yields.

Subsequent studies have shown that that fertilization effect is actually smaller than initially thought. And studies that combine CO2 fertilization with anticipated changes in temperature and precipitation over the next century indicate that we can expect to see 15% to 25% reductions in the yields of several staple food crops, particularly in the tropics. We also anticipate complex changes in the biology of agricultural plants and the pests and pathogens that attack them, as well as the pollinators on which many of them depend.

As temperatures rise, parts of the world will become simply incompatible with prolonged physical labor and many farmers in those regions will lack the resources to replace their labor with mechanization. Fisheries assessments around the world have suggested that wild harvested fish catch peaked over a decade ago and has been falling by about 1% per year. And ocean warming will reduce total fish biomass while at the same time pushing the remaining fish stocks up towards the poles and away from the tropics.

The impacts on livestock and animal husbandry are not very well understood, but increasing heat exposure in the context of growing water scarcity in some regions is a concern. So overall, we're faced with this uncomfortable requirement that we need to essentially increase food production by about 70% over the next 40 years in order to keep up with demand at the same time that climate change is threatening to reduce yields and to push our food production toward the poles and away from the regions where we expect to see most of the world's population growth. In that context we become increasingly dependent on international trade and the prospect of food price lability leaves the poor, including the poor here in the United States, especially vulnerable to food shortages.

And then there are surprises. It's not possible to fundamentally change all the biophysical conditions within which we live without encountering surprises and I want to tell you about one such surprise from our own research. So following on a few small studies done in greenhouses and chambers that indicated that agricultural crops grown at elevated carbon dioxide levels had significantly reduced nutritional value, we decided to investigate that more comprehensively using the free air carbon dioxide enrichment or FACE methods, which is now the gold standard for doing this kind of research.

And by growing crops in these open field conditions that you can see inside a ring of carbon dioxide emitting jets it's possible to expose identical cultivars of the same food crops to the exact same field conditions except that the plants inside the ring are experiencing elevated carbon dioxide. In our experiments that level was about 550 parts per million, which is essentially where we expect the world to be in about 50 years. In that way you can isolate the effect of carbon dioxide on these plants but otherwise have them growing in natural conditions. In our experiments we grew 41 cultivars of 6 important staple food crops on 7 locations across 3 different continents over 10 years.

And by analyzing that large data set we were able to show that yes indeed rising concentrations of carbon dioxide are threatening global human nutrition. Overall, what we found is that all c-3 crops, which is essentially most of what we all eat show significant reductions in iron and zinc. The c-3 grains like rice and wheat also showed significant reductions in protein, while c-4 crops were less effective.

The reason this matters is that iron and zinc deficiency are huge public health problems today, affecting about 2 billion people at a cost of around 63 million life years lost annually. Then to try to understand what these changes in crop nutrients actually meant for risk of micronutrient deficiency in people we went ahead and modeled the dietary intake for the populations of 152 countries around the world. And we found that there are around 2.75 billion people who get at least 70% of their dietary zinc and/or iron from the kinds of c-3 crops that are losing zinc and iron.

Our modeling studies suggested that the carbon dioxide effect alone could push up to 200 million people into new onset zinc deficiency. In addition to exacerbating the existing deficiency in around a billion people. And we have now completed and are about to publish similar studies looking at effects on iron and protein, and we found similar effects. And again we found our most vulnerable populations to be in Africa and South Asia.

I think that I would argue that these findings are important on their own, but I also think that they illustrate a dimension of the conversation that we're having today that I'd like to emphasize about the impacts of climate change on health. If we'd sat down 10 years ago and tried to think what the effects of anthropogenic carbon dioxide emissions might be on human health, none of us would have anticipated that one effect would be to make our food less nutritious. But we can't fundamentally disrupt and reconfigure most of the natural systems around our planet without encountering unintended consequences. And I would argue that these complex, uncertain, difficult to anticipate effects of climate change on health may be just as important as the effects that we're starting to understand.

Noah Leavitt: That was Sam Myers at the recent climate and health meeting in Atlanta. Coming up next week you'll hear from Lise van Susteren, an advisor board member of the school's Center for Health and the Global Environment. She'll be talking about the effects of climate change on mental health. And if you'd like to watch the full conference, we'll have a link on our website, hsph.me/thisweekinhealth. You can also find links to the first two episodes of our series on climate change. And that's all for this week's episode, I'm Noah Leavitt. A reminder that you can always find us on iTunes, SoundCloud, and Stitcher.

See transcript

Noah Leavitt: Coming up on Harvard Chan, This Week in Health, part four of our series on climate change.

Lise Van Susteren: When the place you call home is burned down, blown away, dried up, flooded, see injuries, illness, and death, the mix of fear, anger, sorrow, and trauma can easily send the person to the breaking point.

Noah Leavitt: In this week's episode, how changes to the environment will have wide-ranging effects on mental health and why it's critical to take action now.

Noah Leavitt: Hello and welcome to Harvard Chan, This Week in Health. It's Thursday, March 9th, 2017. I'm Noah Leavitt.

Amie Montemurro: And I'm Amie Montemurro This is part four of our series examining the links between climate change and health. In previous episodes, we've talked about how climate change is likely to force people from their homes, affect our food supply, and cause a spike in some infectious diseases.

Noah Leavitt: This week, though, we're taking a closer look at something that's not often discussed when talking about climate change, mental health. In a few minutes, we'll be playing another clip from the recent climate and health meeting in Atlanta.

Amie Montemurro: Last week, you heard from Sam Meyers about the effects of climate change in our food supply. And he outlined how environmental changes will affect what we can grow, where we can grow it, and, in the end, make our food less nutritious. If you missed that episode or any of our other climate change podcasts, you can visit hsph.me/climatepodcast to listen.

Noah Leavitt: This week we'll be sharing a presentation from Lise Van Susteren, a psychiatrist and an advisory board member for the Center for Health and the Global Environment. Over the next seven minutes, she'll explain that climate change is likely to be a root cause of mental health issues but can also act as a threat multiplier. It will make existing mental health problems worse. Take a listen.

Lise Van Susteren: Everything related to climate change, either directly or indirectly, all the losses, injuries, illnesses, displacements, carry with them an attended emotional toll that must be included as we tally up the psychological impacts of climate change. So I'll start with a few of the mental impacts for which we have precise data and then move on to those for which we do not.

We know of the link between extreme climate and weather events to aggression. For each standard deviation of increased temperature and rainfall, we can expect a 4% increase in conflict between individuals and a 14% increase in conflict between groups. The findings are valid for all ethnicities and regions, so more assaults, murders, and suicides. And increase in unrest all over the world should come as no surprise.

Air pollution forming more readily at higher temperatures with particulate matter crossing into the brain via the olfactory nerve, causing neural inflammation linked to multiple mental and neurologic problems, cognitive decline in all age groups, including Alzheimer's and other neurodegenerative disorders such as Parkinson's disease and ALS. It is linked to autism and psychiatric disorders.

The American Psychological Association reports that children exposed in utero to air pollutants were more likely to have symptoms of anxiety or depression. Emergency room visits for panic attacks and threats to commit suicide are higher on days with poor air quality. Exposing workers to increasing levels of CO2 has significant impact on their cognitive functioning. The testing at indoor concentrations to which Americans are frequently exposed shows the most serious decline in our ability to think strategically, to use information, and to respond to a crisis. Not good.

But not everything that counts can be counted. Indeed, it is the inchoate insidious complex and unconscious psychological states driven by climate trauma not lending themselves to studies in precise numbers that are the most profoundly damaging and drives systemic emotional conditions society will find difficult to treat and surmount. We must think about it, the balance between the need for data with the need to connect emotionally. Because emotional connection is at the heart of what moves people to action. And action now turns on our success in part, at least in stirring empathy.

When the place you call home is burned down, blown away, dried up, flooded, when you lose your possessions, maybe your pets, your livelihood, your community, see injuries, illness and death, the mix of fear, anger, sorrow, and trauma can easily send the person to the breaking point. Mental health professionals are seeing a full range of psychiatric disorders, PTSD, major depression, generalized anxiety, a rise in the abuse of drugs and alcohol, domestic violence, most often against women, and a rise in child abuse.

Some of us are lucky enough to be at a distance from the world's climate disasters. But we're not potted plants sitting here. This is empathic identification with the victims. It is painful seeing people drowned, burned, flooded, starved, right?

Special populations that are at risk: children, the elderly, the sick, the disabled, the mentally ill of course, the poor, those living in the bull's eye of disaster-prone areas along coastlines and rivers, tornado alleys, inner cities with the heat island effect, first responders, climate Cassandras who suffer from pre-traumatic stress disorder in the grip of images of future disasters they can't put out of their minds.

In the first published climate change delusion, a 17-year-old Australian boy had to be hospitalized for refusing to drink water believing it would cause millions in his drought-ridden country to die of thirst. The Melbourne Children's Hospital doctor who treated him told me he has a clinic full of children with climate anxieties. Though the result of multiple forces, climate change is both a threat multiplier and a root cause of the mental health crises from the explosion of refugees today searching for safety, destabilization of regions with groups dangerous to world security rising in these feral conditions.

In Europe, a sharp turn to the far right politically, the once open question about America was answered in November. In times of peril and scarcity, people regress. They turn to what they perceive as strong leaders to protect them and are willing to give up their freedoms and values in exchange for perceived security. And fears often flipped to a more empowering form, anger, explaining why hearing about scary climate change kind of vote so much aggression.

The experiences of citizens stranded at the Superdome in New Orleans in the days after Katrina are an example of how quickly our systems can be overwhelmed and our faith in them turned upside down. Faith in a functional government is the sine qua non known of a stable society. And when disasters are no longer experienced solely as acts of God or nature but derived from the behavior of humans, it will be much tougher on us.

Because what happens from intentional negligence is harder to put behind us than what happens accidentally. Carried by an on/off switch, the activation of a human gene for stress in the face of trauma can be passed on to succeeding generations compounding the toll. A new term has been coined, soul nostalgia, to describe the pain as seeing lands that once gave the treasured sense of home now lost or irreparably damaged.

Should I have a baby is a question increasingly being asked by young people worried about the carbon cost of bringing another person into the world. A doctoral student anthropology at Stanford and one of his friends, who I'm in contact with, have been discussing rational suicide in the face of climate and carbon impacts. As we register the warning that, by mid-century, 30% to 50% of species may be on the path to extinction and considering the life sustaining biodiversity, the overwhelming beauty and complexity of nature inspiring us with awe and wonder, what our friend Eric chivvying would likely ask, is the cost not only to human health but the cost to our souls?

When we put people in harm's way, there's a name for it. It's called aggression. To our children, though they are not yet calling it this, it's clearer every day that destructive inaction on climate- and this is my professional opinion- will be experienced as child abuse with all the attendant mental health impacts we would expect.

Amie Montemurro: That was Lise Van Susteren on the effects of climate change and mental health.

Noah Leavitt: As we mentioned at the beginning, if you missed any of our past episodes on climate change in health, you can visit hsph.me/climatepodcast to catch up on what you missed.

Amie Montemurro: In next week's episode, we'll be taking a closer look at the growing use of nanotechnology in foods. We'll be discussing the benefit of nanoparticles as well as some of the potential risks that scientists are now exploring.

Noah Leavitt: That's all for this week's episode. I'm Noah Leavitt.

Amie Montemurro: And I'm Amie Montemurro. A reminder that you can subscribe to this podcast on iTunes and Sticher or listen any time at souncloud.com/harvardpublichealth.

# data[].attributes.attachment_link.description
Noah Leavitt: Coming up on Harvard Chan, This Week in Health, Climate Change and Our Health. Ari Bernstein: When you change the climate, you sort of change the rules of the game for human civilization. Noah Leavitt: In this week's episode, an in-depth conversation about the effects of climate change and the steps we can take to reduce the damage.

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Global temperatures rising means that diseases spread more easily. 

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Global temperatures rising means that diseases spread more easily. 

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There are four arguments as to how climate change is related to the spreading of infectious diseases. As weather patterns change, the risk of infectious diseases around the world increase because of the misplacement animals and migration through humans and animals. Air pollution particles allow viruses to become airborne and more deadly, prime example being coronavirus in New York City. Due to ice and permafrost melting, ancient diseases may reemerge because the pathogens can be released and our immune system would be unprepared. Global warming could be able to cause mutations that resist our immune system, such as fever not being able to fight off infections because diseases might develop a heat tolerance.

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Fighting infectious diseases: The connection to climate change

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Four reasons the battle against infectious diseases and pandemics is also about the fight against climate change.