Skip to Main Content

How climate change affects public health

Yale Medicine Magazine, 2009 - Winter


In 1967 U.S. Surgeon General William Stewart, M.D., announced that it was time to “close the book” on infectious diseases. There was a hitch to that announcement, said Mary C. Pearl, Ph.D. ’72, at a talk in November sponsored by The Elihu Club and Tropical Resources Institute: “No one alerted the bacteria and viruses.”

The diseases that have since emerged are deadlier and more expensive to fight, said Pearl, president of the Wildlife Trust, a conservation science group. And more than 61 percent of these diseases—including SARS, avian flu, Lyme disease and West Nile virus—have jumped from animals to humans. They’re also, she said, the result of human damage to the environment.

In 2006, the Centers for Disease Control and Prevention declared climate change to be the “largest looming public health challenge we face,” she said. Among its effects are excessive heat that stresses the heart; pollution that attacks the lungs and heart; water- and vector-borne diseases; more frequent floods and drought; and more environmental refugees, leading to overcrowding, civil unrest and ideal conditions for disease proliferation.

“Emerging diseases originate where there are lots of people living in rapidly changing ecosystems,” Pearl said. “Biodiversity is a buffer.”