Previous attribution studies have quantified the effects of climate change on individual Atlantic storms: For example, researchers estimated that up to 38 percent of the extreme rainfall that Hurricane Harvey dumped in southeast Texas in August 2017 can be attributed to climate change. Dr. Reed was among the researchers who confirmed that climate change also played a role in Hurricane Florence in 2018 and Hurricane Dorian in 2019.
The new study is unusual in that it examined the effects of climate change not on a single hurricane but on an entire hurricane season, including not just the headline-grabbing storms but seemingly ordinary ones as well. Dr Reed said the findings provided strong evidence that the anthropogenic impact was not an anomaly confined to big events like Harvey.
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“If you do this objectively for an entire season, you get similar results,” he said.
Rosimar Rios-Berrios, a research meteorologist at the National Center for Atmospheric Research who was not involved in the new study, said examining an entire hurricane season rather than individual storms provided a greater degree of confidence that the findings accurately reflected the role of the climate. change.
“There is a lot of power in studying individual events, but in the end, a single event is not enough because every hurricane is different,” he said.
A separate analysis published Monday found that climate change likely also increased the intensity of rainfall from two vicious tropical storms that hit southeastern Africa earlier this year. But the researchers said that due to a dearth of high-quality weather data for that region, they were unable to measure the precise influence of global warming on those storms.
Dr. Reed noted that the same methodology his team employed could be used to quantify the impact of climate change on a storm in near real time, or to illustrate how much worse storms will get if nations continue to burn fossil fuels.
The study released Tuesday compared the 2020 hurricane season as we experience it to the hypothetical 2020 hurricane season in a world that has not been warmed by human activities. Since the 19th century, the burning of oil, gas and coal has increased the average global temperature by 1.1 degrees Celsius or 2 degrees Fahrenheit. It’s also possible to compare the season experienced with the version that might occur after, say, 1.5 or 2 degrees Celsius of warming, the threshold beyond which scientists say highly destructive storms become significantly more likely.
“It’s important not to plan for the 2020 hurricane season in the future,” Dr. Reed said. “It’s to plan for what the 2020 hurricane season would look like plus climate change in the future.”
Raymond Zhong contributed report.