Paul Epstein, M.D., of Harvard’s Center for Health and the Global Environment, is perhaps the premier medical researcher working on human health in the changing climate. He has co-written, with journalist Dan Ferber, a new book called Changing Planet, Changing Health: How the Climate Crisis Threatens Our Health and What We Can Do About It. I had the opportunity to ask him some questions about the book earlier this week.

How does climate change threaten human health?

The most obvious way is through heat waves. Heat waves are increasing in duration, intensity and frequency — but also in the nature of them. Since 1970, temperatures at night have gone up twice as fast as daytime temperatures. There’s no relief at night, which makes heat waves more lethal.

There are also rises in asthma and allergies and infectious disease, especially related to flooding and other extreme weather events. Drought is a deepening issue in much of the world. Finally, we are facing food and security issues all of a sudden, and there are several reasons for that and one is extreme weather events, like the heat wave that killed wheat crops last year.

You use Hurricane Mitch as an example in the book. How do big storms affect health in their wake?

Hurricane Mitch brought 6 feet of rain over 3 days to Honduras and other parts of Central America. There were 11,000 deaths. Clusters of infectious diseases follow the storms. There were huge clusters of malaria, cholera and rodent-borne [diseases].

The [2008] Pakistan floods displaced 20 million people; they’ve also had malaria, cholera, measles and other diseases. The measles come from crowding among refugees. You have people who are malnourished because the floods hurt the grain crops, and that also increases vulnerability to infectious diseases.

If we make the connection between human health and climate change, do you think that will carry over and persuade industrialized nations like the U.S. to shift to renewable energy?

I’m hopeful. I can’t tell you how it’s going to happen, because people are resistant but there’s a well funded well orchestrated campaign to keep up the doubts. But it’s not just about polar bears; it’s about us. There’s been an enormous increase in asthma in this country—it’s more than doubled since 1980.

But here’s five problems related to burning fossil fuels, even without climate change:

CO2 increases pollen production, and makes allergenic proteins stronger. Particulate pollution globs onto pollen and help deliver them deep in our lungs. Ozone primes the allergic response, and fossil fuel causes more ozone. And, with climate change, allergy and asthma season has increased by 2 to 4 weeks.

You come out against nuclear power, a controversial position even among environmentalists. Why did you decide to do that?

We looked at [climate] solutions through the health lens, and that’s not as fluffy as one might think. There are several unresolved issues with nuclear power: storage, security and safety—safety may be the least of it, but it makes nuclear power costly to build.

Storage is unsolved. And we have to think ahead, and I’m very afraid of replacing carbon pollution with nuclear pollution and winding up with lots of nuclear material that harms people, animals and plants.

The U.S. isn’t the hardest hit by the effects you write about. Rather, it seems to be developing nations. Who will take the lead in taking the kinds of steps you argue for, like the development of an adaptation fund managed by the U.N.?

I think it’s a myth that the U.S. is not affected. We’ve had severe floods, we’ve had a storm system in the Midwest with tornadoes in record numbers; the whole jet stream is displaced. We’re seeing droughts, floods, wild winter weather. Lyme disease is galloping north, and we’ll be threatened with heat waves this summer.

How can we get past the distrust between developing nations—who’ll be hardest hit—and industrialized nations, who take the lion’s share of the blame for climate change that has plagued U.N. talks?

It revolves around funds. There needs to be an international fund for the transfer of technology, the manufacture of technology. The Montreal protocol was only agreed upon when there was a fund put up, and the magnitude of funding for green energy is far greater than for the ozone.

Transferring money from the overloaded, hyperactive financial sector is appealing as a way of creating the hundreds of millions of dollars to make every nation safe. A thousand economists, including Jeff Sachs, signed on supporting the Tobin Tax. It’s been primarily about disease, but it could be a source for clean technology and millennium development goals. 

You warn of climate tipping points that could cause the climate to change dramatically within a decade. That’s really scary. How serious is that risk, and what will determine if it happens or not?

The climate is unstable, particularly of ice melting. We know that historically, the climate has tripped and flipped several degrees within a couple of years. The key thing to watch is North Atlantic circulation — as more ice melts, you get layer of cold, fresh water across the surface, and that can interfere with water turnover. As more arctic ice melts, the ocean absorbs more heat, warming is accelerated.

The climate instability is the scary part. The hopeful part is that systems like to go to equilibrium; it’s possible it could even out at another state.

You’ve mentioned a few things in our conversation that some people insist don’t have to do with climate change, such as the Russian grain failure and the Midwestern tornadoes. Why are you linking them with changes in the climate?

Dice is rolled to increase chance of extremes. Katrina wouldn’t have been as strong in 1980 because the water was warmer in 2004.

Kevin Trenberth is a climatologist at the National Center for Atmospheric Research. What he’s said is what I agree with, which is that everything now is affected by natural vulnerability and climate change. It’s absurd to say this event is climate change and this one isn’t: every weather event is affected by climate change.

We used to say no one event is diagnostic of climate change. That’s passé, we know the climate is changing and everything we see is affected by it.