October 11, 2021

Human-induced climate change may affect 85% of the global population, researchers say

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Scientists are beginning to paint a clearer picture on just how many people will be affected by climate change if current warming trends continue.

About 85% of the world's population already lives in areas experiencing the affects of human-induced climate change, according to a study published in Nature Climate Change on Tuesday.

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Researchers in Berlin compiled data from more than 100,000 impact studies analyzing detectable environmental signals of human-induced climate change, finding that the evidence for how climate change is impacting communities is continuing to grow.

"In almost every study where we have enough data, we can see, [the world] is getting hotter, and it's getting hotter in a way that is consistent," Max Callaghan, a researcher at the Mercator Research Institute on Global Commons and Climate Change in Berlin and one of the authors of the study, told ABC News.

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The Windy Fire blazes through the Long Meadow Grove of giant sequoia trees near The Trail of 100 Giants overnight in Sequoia National Park on Sept. 21, 2021, near California Hot Springs, Calif.

The research also looked at how rising temperatures change precipitation patterns and affect crop yields and local ecosystems, and it found that human-attributable changes in temperature and precipitation are now occurring in 80% of the world's land area, where about 85% of the global population resides, Callaghan said.

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The impacts will be felt the strongest in the least developed countries, but little is known about exactly what those effects will look like, he added, describing the lack of data as an "attribution gap" that needs to be filled.

"In high income countries, almost all of those people live in an area where there is also lots of evidence about how that warming trend affects other systems," he said. "But in low income countries... there is little evidence about how that warming trend is affecting other things."

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Cars and trucks left stranded in high water on an expressway after flash flooding in New York, from Hurricane Ida, Sept. 2, 2021.

The new research is allowing scientists to attribute with near-certainty that global temperatures are increasing because of human influence on the planet, Callaghan said. While previous studies often focus on possible scenarios by 2050 or 2100, it is clear that climate change is "already happening."

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Countries will need to significantly reduce greenhouse gas emissions in the near future to mitigate the extremity of pending disasters, the researchers said.

"As long as we continue burning fossil fuels, things will get worse," Callaghan said. "Until we reach net-zero, things will continue to get worse."