The Coming Climate Change Plague

Scientists warn that exotic diseases such as Ebola, SARS, and West Nile virus will become increasingly common as the world warms.

(Photo: Seyllou/AFP/Getty Images)

Feb 18, 2015· 1 MIN READ
Padma Nagappan is a multimedia journalist who writes about the environment, renewable energy, sustainability, agriculture, and biotechnology.

Ebola was not an aberration—it may well be the future as climate change accelerates the spread of exotic diseases around the world, according to a new study.

“Take SARS, West Nile virus.... It’s actually much easier for these pathogens to be introduced in new regions than we thought earlier,” said Daniel Brooks, a zoologist with the University of Nebraska–Lincoln. "All they need is to come into contact with hosts that are susceptible.”

In the study, published this week in the journal Philosophical Transactions of the Royal Society B, Brooks and coauthor Eric Hoberg found that a changing climate will drive migration of birds, fish, and animals to new regions. Pathogens will hitch a ride, finding hosts that have no immunity to various diseases.

We’re not talking about outbreaks in remote areas of the world but much closer to home.

Brooks studied parasites in the tropical region of Costa Rica, while Hoberg, who is with the United States Department of Agriculture, tracked parasites in birds and mammals in the Canadian Arctic. Their findings were alarmingly similar.

Both zoologists found lots of unknown parasites, but what surprised them was that even known parasites now resided in new hosts in regions far from the organisms’ origins.

When they dug deeper, they found the phenomenon had occurred during earlier episodes of significant climate change, such as in the Ice Age.

“In the Ice Age, climate change pushed a lot of animals and plants down south, where they mixed together with local species, and when that period ended, they pushed back up north,” Brooks said. “But by that time, they’d already exchanged pathogens between the northern and southern species, so what moved north was a completely new set of pathogens.”

Any kind of movement creates the possibility for any pathogen and host to come in contact with each other.

Brooks cautioned that we should expect exotic diseases to become more common. Public health officials will need increasingly to worry about diseases spread to humans by animals.

New diseases are also likely to have a huge economic impact and affect the food supply, according to the scientists.

“This is essentially about food security and food safety,” said Hoberg. “Changing temperature drives distribution of animals. When they move north—to the Canadian Arctic, for example—they come in contact with local animals like reindeer, caribou, and musk oxen, which get exposed to new pathogens, which can reduce their numbers and hurt the food supply of northerners.”

The climate will also change the locations where crops can be grown, and as agriculture moves north, it will carry pathogens into new regions.

But neither scientist predicts it will be all doom and gloom.

“The good news is, we know what to do to mitigate it,” Brooks said. “We can’t stop emerging diseases, just like we can’t stop climate change, but we can prepare for it.”