Climate change is likely to affect the spread of more than half of known human pathogenic diseases, according to a new study by researchers from the University of Hawaiʻi at Mānoa, published in the journal Nature Climate Change, ABC News reports.

The study, a survey and analysis of published literature on pathogenic diseases—those caused by viruses, bacteria, and fungi, as well as those passed to humans by animal and organic vectors—found that the spread and virulence of 58 percent (218 of 375) of known human infectious diseases have been or currently are aggravated by climatic hazard, suggesting that as global warming and weather extremes persist in the coming century, the spread of known diseases such as malaria and novel viruses like COVID-19 will become more common and outbreaks more frequent.

The study found that climate events—heat waves, droughts, wildfires, extreme precipitation, floods, and sea level rise—that trigger population shifts, degrade sanitation, and disrupt food supplies bring humans closer to pathogens. Such events are also increasing the geographical range of disease carrying organisms—one of the most common ecological indications of climate change—bringing pathogens closer to humans. Moreover, warming in tropical and temperate regions has triggered an explosion of mosquito populations, biting rates, and viral replication, increasing the transmission of diseases such as West Nile virus, while at higher latitudes pathogens and vectors are now surviving winter, aggravating outbreaks of viruses like anthrax.

According to the study’s lead author, Camilo Mora, COVID-19, as one example of an animal-to-human transmission of a novel virus, would have been unlikely without global warming. “The magnitude of the vulnerability, when you think about one or two diseases—okay, sure, we can deal with that,” said Mora. “But…you're talking about 58 percent of the diseases…[that] can be affected or triggered in 1,000 different ways. So that, to me, was also revealing of the fact that we’re not going to be able to adapt to climate change.”

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