A new study is making waves in the media, claiming to finally address the question of man-made global warming’s role in Hurricane Harvey’s record-setting rainfall. There’s one huge caveat: the scientists didn’t actually study Hurricane Harvey itself.
Massachusetts Institute of Technology (MIT) professor Kerry Emanuel, a renowned hurricane expert, and his colleagues published their findings on Monday, claiming global warming increased the of risk Hurricane Harvey-level rainfall in southeastern Texas grew since the last century.
There’s one huge caveat: Emanuel didn’t actually study Hurricane Harvey itself.
Instead, Emanuel’s study is based on thousands of climate model runs to find out the odds a storm will bring the amount of rainfall Hurricane Harvey did when it made landfall in late August 2017.
Instead, his study models the statistical likelihood of Harvey-level rainfall based on a linear projection of how storms could change under a scenario with massive amounts of global warming.
Hurricane Harvey broke Texas rainfall records when it hit, dumping large amounts of rain over the greater Houston area for about five days. Cedar Bayou, outside Houston, saw nearly 52 inches of rainfall, breaking an all-time U.S. record.
Emanuel concluded there’s “a sixfold increase” in the odds of Harvey-level rainfall pummeling Houston in any given year. Emanuel estimated an 18 percent chance of Harvey-level rainfall by the end of the 21st Century.
At one point, Emanuel noted “Harvey’s rainfall in Houston was ‘biblical’ in the sense that it likely occurred around once since the Old Testament was written.”
But special circumstances were at play for Hurricane Harvey.
Harvey’s rainfall was only able to break records because it stalled over Texas, blocked by a high pressure ridge in the west. The high pressure ridge kept Harvey over Texas longer than it otherwise would have, concentrating rainfall over a smaller area.
“There is no question that the extraordinary magnitude of Harvey’s rain was mostly because it stalled,” Emanuel told TheDCNF.
Media coverage of the study glossed over this inconvenience, with The Washington Post reporting that “Climate change upped the odds of Hurricane Harvey’s extreme rains, study finds.”
The Atlantic ran with the ridiculous headline: “Global Warming Really Did Make Hurricane Harvey More Likely.” Apparently the writer didn’t read the study itself.
Some climate scientists were quick to blame global warming for Hurricane Harvey’s devastation. Climate scientist Michael Mann said warmer-than-normal temperature in the Gulf of Mexico gave Harvey more power and allowed it to hold more moisture, but other scientists were quick to shut him down.
So far, scientists have found little to no evidence global warming is having an impact on hurricanes. The National Oceanic and Atmospheric Administration found in March 2017 that it’s “premature to conclude that human activities — and particularly greenhouse gas emissions that cause global warming — have already had a detectable impact on Atlantic hurricane or global tropical cyclone activity.”
Emanuel was one of the scientists who came out linking Harvey’s devastation to global warming. Now, he’s published a study on this.
Studies like this usually take time to get published, but Emanuel “decided to use his status as a member of the National Academies of Science, which let him pick his own peer reviewers, who were likely to be friendly and get the review done quickly,” Ars Technica reported.
That means the “findings probably haven’t faced as rigorous a review as they might have,” Ars Technica reported, but it does show Emanuel is confident in his hurricane modeling, which has already been peer-reviewed. Emanuel’s study was funded, in part, by the National Science Foundation.