Study: Worsening of diseases connected to climate hazards
Climate hazards such as flooding, heat waves and drought have worsened more than half of the hundreds of known infectious diseases in people, including malaria, hantavirus, cholera and anthrax, a study says.
Researchers looked through the medical literature of established cases of illnesses and found that 218 out of the known 375 human infectious diseases, or 58%, seemed to be made worse by one of 10 types of extreme weather connected to climate change, according to a study in Monday’s journal Nature Climate Change.
Doctors have long connected disease to weather, but this study shows how widespread the influence of climate is on human health.
“If climate is changing, the risks of these diseases are changing,” said study co-author Dr. Jonathan Patz, director of the Global Health Institute at the University of Wisconsin-Madison.
Doctors such as Patz said they need to think of the diseases as symptoms of a sick Earth.
“The findings of this study are terrifying and illustrate well the enormous consequences of climate change on human pathogens,” said Dr. Carlos del Rio, an Emory University infectious disease specialist, who was not part of the study. “Those of us in infectious diseases and microbiology need to make climate change one of our priorities.”
In addition to looking at infectious diseases, the researchers expanded their search to look at all types of human illnesses, including noninfectious sicknesses such as asthma, allergies and even animal bites to see how many maladies they could connect to climate hazards in some way, including infectious diseases. They found a total of 286 unique sicknesses and of those, 223 seemed to be worsened by climate hazards.
Longtime climate and public health expert Kristie Ebi at the University of Washington cautioned that she had concerns with how the conclusions were drawn and some of the methods in the study. It is an established fact that the burning of coal, oil and natural gas has led to more frequent and intense extreme weather, and research has shown that weather patterns are associated with many health issues, she said.
“However, correlation is not causation,” Ebi said in an email. “The authors did not discuss the extent to which the climate hazards reviewed changed over the time period of the study and the extent to which any changes have been attributed to climate change.”
But Dr. Aaron Bernstein, interim director of the Center for Climate, Health, and the Global Environment at Harvard School of Public Health, Emory’s del Rio and three other outside experts said the study is a good warning about climate and health for now and the future. Especially as global warming and habitat loss push animals and their diseases closer to humans, Bernstein said.
“This study underscores how climate change may load the dice to favor unwelcome infectious surprises,” Bernstein said in an email.