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The Zoologist Who Says Climate Change Will Usher in a New Age of Disease

Governments are unwilling to address the new rise in outbreaks, he says.
​A person stands in protective equipment at a "Fighting Ebola Workshop." (Photo: Ted Eytan)

​Over the last couple days, zoologist Daniel Brooks' findings about how climate change is fueling the spread of infectious diseases have b​een inspired despairing headlines around the world. But when I spoke with the man over the phone, he was optimistic—for someone who thinks huma​nity is facing "the death of a thousand cuts," anyway.

"It's serious, but it's not bleak," Brooks said of the broader effects of climate change. "Nobody thinks all species are going to get wiped out."

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The conclusions drawn from his research are, indeed, serious. Over 30 years, Brooks and his colleague Eric Hoberg have studied how climate change has affected parasites in very different ecosystems, from the tropics to the Arctic. They discovered that pathogens are being spread more widely and more easily than previously thought, meaning outbreaks of Ebola, West Nile virus, and other diseases will be more frequent in the future.

"Climate change causes movement of species and new connections of species," Brooks said. "As you get hosts moving around, the pathogens move around as well. And then the pathogens come into contact with hosts they've never seen before."

The introduction of pathogens to new environments will cause more frequent and expansive epidemics.

"It's not that there's going to be one 'Andromeda Strain' that will wipe everybody out on the planet," Brooks said in a st​atement, referencing a science fiction film about a deadly pathogen by that name. "There are going to be a lot of localized outbreaks putting pressure on medical and veterinary health systems. It will be the death of a thousand cuts."

"It's not that there's going to be one 'Andromeda Strain' that will wipe everybody out on the planet"

Those findings aren't necessarily news. It's been l​ong expected that climate change would cause shifts in ecosystems and lead to the spread of disease. Brooks himself calls this a "predictable result of climate change" in the study. However, he said the effects of climate change on biodiversity are much broader in scope than scientists anticipated.

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"Some scientists saw the biodiversity crisis and climate change in the 1950s, but it was another 20 years before we really recognized the scope of the problem," he said. "Only now are we beginning to see the biodiversity issues are part of a much bigger problem, and every aspect of it has major socioeconomic implications."

His research also challenges the widely-held assumption that parasites don't easily shift hosts, meaning outbreaks of emerging diseases will be more common than previously thought.

"This idea that all of us were trained to believe was that parasites were so adapted to their hosts they didn't jump around much, but what we have found is parasites are changing hosts all the time," he said.

This discovery calls for a "fundamental conceptual shift" regarding the way pathogens acquire new hosts, Brooks said. As climate change pushes parasites to new regions, hosts who have never been exposed to the pathogens are actually more susceptible, not less, as they haven't had the chance to build up any resistance.

Brooks said it is too late to think about reversing climate change, but he is optimistic about the ways humans can respond to it.

"The thing about climate change, because it's a global phenomenon, we aren't going to be able to stop the emergence of disease, but we can anticipate it, we can adapt to it, we can slow it down and try to minimize the damage," he said.

He said the best way to respond to the rise in these diseases is to take inventory of what pathogens are out there, because, as he says, "what you don't know can hurt you."

"To reduce the amount of exposure, we have to anticipate where the pathogens are, where they could move to, how they can be transmitted to humans or livestock or crops or important wildlife," he said. "This is the only way to reduce the economic burden of emerging disease which is inevitable during a period of climate change, like this one."

When Brooks discusses government response to climate change, his optimism wavers. He said adapting to climate change will require a major shift from politicians, he said, who first have to admit that it's real."At the moment we are very unprepared," he said. "We are responding after the fact, in crisis mode. We need to anticipate and be as proactive as possible."

"There's no sense of urgency on the part of people who control the agenda, but the good thing is there are scientists who have a good idea of what to do when people who make policy decide to talk to us," Brooks said.