Diseases such as Zika, malaria, dengue, chikungunya and even Covid-19 have been exacerbated by climate impacts such as heatwaves, wildfires, extreme rainfall and flooding, the paper found. In total, there are more than 1,000 different pathways for these various effects to exacerbate the spread of disease, a range of threats “too many for comprehensive societal adaptations,” the researchers wrote. Global warming and changed 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 have displaced people, bringing them closer to pathogens that cause outbreaks of gastroenteritis and cholera, while climate impacts have weakened people’s ability to deal with some pathogens—drought, for example, can lead to poor sanitation , resulting in dysentery, typhoid fever and other diseases. “We’re opening a Pandora’s box of disease,” said Camilo Mora, a geographer at the University of Hawaii who led the research. “Because of climate change, we have all these triggers around the world, over 1,000 of them. There are diseases out there waiting to be unleashed. It’s like poking a lion with a stick – at some point the lion will come and bite us in the ass.” The researchers analyzed more than 70,000 scientific papers that analyzed the relationships between different climate risks and infectious diseases. Some of these papers look at evidence stretching back 700 years, before the onset of the human-caused climate crisis. Of the 375 different infectious diseases reported in these papers, the researchers found that 218, more than half, have been exacerbated by the climate effects that are now becoming more common due to global warming. A smaller proportion of infectious diseases, about 16%, were reduced by climate impacts, according to the paper published in Nature Climate Change. Kira Webster, a co-author of the study, said that as the disease database grew, “we were both fascinated and saddened by the overwhelming number of case studies available that already show how vulnerable we are becoming to continued rising greenhouse gas emissions.” . Mora said there were likely many ways the climate crisis exacerbated the spread of Covid, such as habitat disruption from fires and floods displacing wildlife, such as disease-carrying bats, into new areas closer to people. Mora said he himself suffered from chronic joint pain after contracting chikungunya during an outbreak in Colombia a few years ago, following a period of heavy rain that caused mosquito numbers to explode. “If there are pathogens that harm us, climate change is trying to get to every single one of them,” he said. “It’s shocking to me that we’re not taking it more seriously.” The World Health Organization has warned that the climate crisis “threatens to undo the last 50 years of progress in development, global health and poverty reduction” and has estimated that an extra 250,000 people will die each year from 2030 to 2050 due to multiplying diseases. such as malaria and diarrhoea, as well as malnutrition and heat stress. The new research is an “impressive mining of what has been studied to show that climate shocks, on balance, make our already daunting task of fighting germs more difficult,” said Aaron Bernstein, director of the Center for Climate, Health and global environment at Harvard University, who was not involved in the study. “Climate science has shown that climate change is making more parts of the world too hot, too dry, too wet, and ultimately too unsuitable for people to sustain a livelihood,” Bernstein added. “Mass migrations of people can cause infectious outbreaks of everything from meningitis to HIV. In short, an unstable climate creates fertile ground for infectious diseases to take root and spread.”
