Science Confirms, Helene Was a Climate Catastrophe

This wasn’t really in doubt, of course. Climate change has progressed past the point where its tendrils of influence are seen in essentially every severe weather event, and the burden of proof should more reasonably be placed on a claim that warming did not play an important role.

But the opposite standard still exists, leftover from a couple of decades of “you can’t blame climate change for individual weather events” refrains. The good news, though, is that scientists have gotten very good and very fast at doing exactly that kind of blaming — like today, when World Weather Attribution released its analysis of the devastating Hurricane Helene. Short version: yes, warming made it worse.

“It is… overwhelmingly likely that the impacts of the hurricane were more severe as a result of climate change,” authors from four countries wrote. “[I]t is clear that the rainfall, wind speeds and conditions leading to Hurricane Helene have all increased due to climate change.”

The researchers found that in the world we live in and its 1.3 degrees Celsius of warming above pre-industrial temperatures, the rainfall Helene brought to the coasts will occur once ever seven years. Inland was another story: the rainfall seen in North Carolina and nearby will come back only once every 70 years. The rain that did fall was made 10 percent heavier thanks to warming, and the three-day total rainfall was 70 percent more likely than before climate change. If we get to 2 degrees C, this event could get 25 percent more likely still.

Helene, and other hurricanes crossing the Gulf of Mexico, are gaining more and more strength thanks to the warmth of the ocean water beneath them, which gives the more power where they hit and more opportunity to travel inland even as they weaken. The ocean temperature that Helene skated over was made as much as 500 times more likely thanks to climate change.

Helene’s death toll has crossed 230 now, and cleanup continues; the economic cost will easily be in the tens of billions of dollars. Its worst impacts fell hundreds of miles from a coast, and thousands of feet above sea level, confounding our baked-in ideas of what a hurricane can do. The roll of climate change in its destruction was clear to the eye, and now the numbers confirm it. Meanwhile, Milton approaches.