Mainstream media outlets ran storiesover the last week attributing the very strong storm and its historic rainfall to climate change, but University of Washington atmospheric scientist Cliff Mass put the brakes on those theories in a new blog post.
According to Mass, the idea that human-caused climate change had any effect on Harvey is more than far-fetched — it’s downright not true.
It’s a lie in other words. In fact, the stories are not based on data at all.
“Most of the stories were not based on data or any kind of quantitative analysis, but a hand-waving argument that a warming earth will put more water vapor into the atmosphere and thus precipitation will increase,” he wrote. “[T]he results are clear: human-induced global warming played an inconsequential role in this disaster.”
He explained: “The proximate cause of the disaster is clear: the extreme rainfall was the result of a hurricane/tropical storm that pulled in huge amounts of water vapor off the Gulf of Mexico (and beyond), and which came into the Texas coast and then stalled for days. All tropical storms/hurricanes bring large amounts of rain during landfall. What was different here was the stalling and sitting over the same region for days.”
Mass says the questions that need to be asked are: Did global warming intensify the storm and cause great rainfall? And did global warming cause the storm to stall over southeast Texas for days?
Mass’ conclusion is a resounding “no.”
The temperatures before the storm were normal.
“Hurricane Harvey developed in an environment in which temperatures were near normal in the atmosphere and slightly above normal in the Gulf,” he wrote. “The clear implication: global warming could not have contributed very much to the storm.”
At most, even using the global warming intensification theory, warming would account for one inch of rain. Since more than 40 inches fell, it’s not significant.
“There is no evidence that global warming is influencing Texas coastal precipitation in the long term and little evidence that warmer than normal temperatures had any real impact on the precipitation intensity from this storm,” he wrote.
Regarding the second question, Mass wrote: “Quite honestly, none of this is supported by observations or models.”
The bottom line in this analysis is that both observations of the past decades and models looking forward to the future do not suggest that one can explain the heavy rains of Harvey by global warming, and folks that are suggesting it are poorly informing the public and decision makers.
They are using hand-waving arguments to push an agenda, which observations, theory, and modeling show to be incorrect. Global warming is a serious issue and mankind must deal with it, but hype and exaggeration of the current effects is counterproductive in the long term.
Instead, Mass suggested the real topic of concern should be on the “lack of resilience of our infrastructure to current extreme weather.”