Fingerprints of climate change are increasingly appearing in extreme weather

Extremely low sea ice in the Bering Sea. Heavy rainfall in the mid-Atlantic United States. Wildfires in northeast Australia.

Examinations of these and 16 other extreme weather events that occurred in 2018 found that all but one were made more likely due to human-caused climate change, scientists reported December 9 at a news conference at the American Geophysical Union’s annual meeting. Insufficient observational data made it impossible to assess the influence of climate change on the one event, heavy rains in Tasmania.

The new report marks the third year in a row that scientists have identified specific weather events that they said would not have happened without human activities that are altering Earth’s climate.

The findings are part of a climate-attribution special issue, called “Explaining extreme events in 2018 from a climate perspective, published online December 9 in the Bulletin of the American Meteorological Society. Over the 11 years that BAMS has published the special issue, it’s included 168 studies examining specific weather events. Of those, 122, or 73 percent, found that climate change likely played some role in the event, the special issue’s editor Stephanie Herring said at the news conference. In some cases, that means the event was more likely to occur due to human actions; in a few studies, researchers have concluded that the event would not have occurred without climate change.

Finding a role is becoming more common; the special issues tied to events in 2017 and 2016 found that climate change was linked to 95 percent of the events studied.

Rather than being a cause for despair, identifying humankind’s role in these events should be seen as a way to provide new data in the fight to prepare for climate change, BAMS Editor in Chief Jeff Rosenfeld said in the news conference. “Instead of stoking fear, I think having real quantifiable information like this puts that human fingerprint in terms that we can actually act [on] without getting overwhelmed.

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