More than half of human diseases caused by pathogens have been exacerbated at some point by impacts linked to the climate crisis, a new and comprehensive study of the link between disease and climate risks has found.
Diseases such as Zika, malaria, dengue, chikungunya and Covid-19 have been exacerbated by climate impacts such as heat waves, wildfires, extreme rainfall and floods. In total, these diverse influences have more than 1,000 different pathways for worsening disease transmission, a cavalcade of “many” threats to broader societal adaptations, the researchers wrote.
Global warming and altered rainfall patterns are expanding the range of disease vectors such as mosquitoes, ticks and fleas, resulting in the spread of malaria, Lyme disease, West Nile virus and other conditions.
Storms and floods displace people and bring them into close contact with pathogens that cause gastroenteritis and cholera, while climate impacts weaken humans’ ability to cope with certain pathogens—drought, for example, can lead to poor sanitation, diarrhea, typhoid fever, and other diseases.
“We’re opening a Pandora’s box,” said University of Hawaii geologist Camilo Mora, who led the research. “Because of climate change, there are these triggers around the world, more than 1,000 of them. There are diseases out there waiting to be unleashed. It’s like we poke a stick at a lion – at some point the lion will come and bite the donkey.
The researchers combed through more than 70,000 scientific papers to examine the links between various climate risks and infectious diseases. Some of these papers look at evidence as far back as 700 years, before the onset of the human-caused climate crisis. Of the 375 different infectious diseases mentioned in these papers, the researchers found that 218, more than half, are currently being worsened by the more common climate impacts of global warming.
A small proportion of infectious diseases, about 16%, were reduced by climate impacts, according to the paper. Published in Nature Climate Change. Kira Webster, co-author of the study, said that as the disease database grew, “we were both fascinated and saddened by the large number of case studies available, which already show how much we are affected by increasing emissions of greenhouse gases”. .
The climate crisis could worsen the spread of Covid in several ways, such as habitat disturbance from fires and floods, which could drive wildlife such as disease-carrying bats into new areas closer to humans. Mora said she contracted chikungunya and suffered from chronic pain in her joints after experiencing a surge in mosquitoes during heavy rains that swept through Colombia a few years ago.
“If we have pathogens that are harmful to us, climate change is trying to get every one of them,” he said. “It’s shocking to me that we’re still not taking this seriously.”
World Health Organization warned The climate crisis “threatens the last 50 years of progress in development, global health and poverty reduction” and estimates that an additional 250,000 people will die each year from 2030 to 2050 from increasing diseases such as malaria and dysentery. as well as malnutrition and heat stress.
The new research is an “impressive mine of what has been studied to demonstrate that climate shocks, on balance, make our difficult task of fighting microbes harder,” said Aaron Bernstein, director of the Center for Climate, Health and Global Environment. Harvard University, which was not involved in the study.
“Climate science shows that climate change is making many parts of the world too hot, too dry, too wet, and ultimately too unsuitable for people to sustain their livelihoods,” Bernstein added.
“Mass migration of people can trigger all kinds of epidemics, from meningitis to HIV. In short, an unstable climate creates fertile ground for infectious disease to establish roots and spread.”
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