Harvey boosts media confidence for linking extreme weather to global warming
Texas National Guard soldiers aid flood victims in Houston on 27 August.
Texas Military Department, CC BY-ND 2.0
Distilling news from Texas that bears on the climate wars, FactCheck.org’s SciCheck declares , “Hurricane Harvey has brought with it both a record amount of rain and questions about how much climate change can be blamed for the storm. Climate change did not cause Harvey, or any other storm, but it makes intense storms like Harvey more likely to occur, scientists say.” An informal sampling of media coverage suggests that the hurricane has led journalists to ratchet up their readiness to presume that likelihood.
Nature‘s editors illustrated the readiness by asserting , “Extreme weather events such as Harvey can be described as ‘unprecedented’ only so many times before companies and governments are forced to accept that such events are the new normal.” Climate Central blogger Andrea Thompson warned two years ago that torrential rains back then were “an example of what Texas—and the globe as a whole—are likely to see more of in a warming world.”
The New York Times gave op-ed space and the headline “Hurricane Harvey was no surprise ” to Stanford University’s Noah Diffenbaugh, editor-in-chief of the American Geophysical Union’s peer-reviewed Geophysical Research Letters. He cautioned that although “seas have risen and warmed, and the atmosphere now holds more moisture, we can’t yet draw definitive conclusions about the influence of climate change on Hurricane Harvey.” But he emphasized that it’s nevertheless “well established that global warming is already influencing many kinds of extremes.” Diffenbaugh summarized: The “odds of catastrophes like Hurricane Harvey are increasing.”
Under the headline “The relationship between hurricanes and climate change ,” Times science writer John Schwartz cautiously cited a draft of a climate science report from 13 federal agencies suggesting that the science connecting hurricanes to climate change is “still emerging.” But he also quoted the view of Texas Tech University climatologist Katharine Hayhoe, an author of the report, that even if global warming doesn’t increase or reduce the number of storms, they do get energy from warm water, which means that a changing climate “can have a role in intensifying a storm that already exists.”
It’s a regularly emphasized combination: caution about attributing causation of extreme weather to climate change plus confidence about attributing intensification to climate change. A USA Today editorial used the headline “Climate change juiced Hurricane Harvey.” At the Washington Post, Chris Mooney quoted MIT’s Kerry Emanuel’s point, made also by climatologist Michael Mann, that “attributing a particular event to anything, whether it’s climate change or anything else, is a badly posed question, really.” Mooney elaborated: “Scientists like Emanuel prefer to speak about climate-related factors that can worsen hurricanes, like Harvey, in specific ways—and about the ways in which certain attributes of Harvey seem consistent with what to expect, more generally, in a warming climate, even if they can’t be causally attributed to it.”
The pre-landfall strengthening of Hurricane Harvey was aided by anomalously warm water in the Gulf of Mexico.
What to expect in a warming climate? To help answer, the Atlantic‘s article “Did climate change intensify Hurricane Harvey?” linked to a color-coded map (right) showing anomalously high water temperatures where the hurricane approached Houston. A short caption told a big story: “Harvey intensified rapidly amid sea surface temperatures in the Gulf of Mexico up to 2.7-7.2°F (1.5-4°C) above average, relative to a 1961-1990 baseline.”
At Vox, climate writer David Roberts published “Climate change did not ‘cause’ Harvey, but it’s a huge part of the story.” He’s irked. He thinks others are saying too little about the connection between climate change and extreme weather. He calls climate change a “threat multiplier” and says it can give a storm that would have arisen anyway its “winning personality.”
New York Times columnist David Leonhardt is irked too. “It’s time to shed some of the fussy over-precision about the relationship between climate change and weather,” he wrote , then continued:
James Hansen, the eminent climate researcher, has used the term “scientific reticence” to describe this problem. Out of an abundance of academic caution—a caution that is in many ways admirable—scientists (and journalists) have obscured climate change’s true effects.
We don’t display the same fussiness in other important areas. No individual case of lung cancer can be definitively linked to smoking, as Heidi Cullen, the chief scientist at Climate Central, notes. Few vehicle accidents can be definitely linked to alcohol, and few saved lives can be definitively linked to seatbelts.
Yet smoking, drunken driving and seatbeltless riding each created a public health crisis. Once the link became clear and widely understood, people changed their behavior and prevented a whole lot of suffering.
Similarly assertive are meteorologist Eric Holthaus and climatologist Mann. In Politico, Holthaus published “Harvey is what climate change looks like: It’s time to open our eyes and prepare for the world that’s coming.” In a Guardian op-ed addressing sea-level rise, warmed ocean waters, and wind effects, Mann concluded “Climate change worsened the impact of Hurricane Harvey.”
But then there’s Wall Street Journal columnist Holman Jenkins, who declared confidently that Harvey’s severity had “nothing to do with climate change.” The WSJ website offers a two-minute video called “The science of why Harvey was so devastating.” It never mentions climate.
For the Competitive Enterprise Institute, blogger and former Trump transition-team head Myron Ebell posted “Climate alarmists exploit Hurricane Harvey to score political points .” He directed readers to what he called an “expert commentary by Dr. Roy Spencer on Hurricane Harvey and global warming.” That commentary takes the headline “Texas major hurricane intensity not related to gulf water temperatures.” It argues that the “flooding disaster in Houston is the chance occurrence of several factors which can be explained naturally.” Spencer authored An Inconvenient Deception: How Al Gore Distorts Climate Science and Energy Policy.
Reuters reported that the US Environmental Protection Agency “rejected a contention by scientists that the historic rainfall from Tropical Storm Harvey was linked to climate change, calling it ‘an attempt to politicize an ongoing tragedy.’”
On 30 August, with the water in Houston finally about to begin receding, the Washington Post‘s Mooney placed online a climate-wars analysis headlined “Katrina. Sandy. Harvey. The debate over climate and hurricanes is getting louder and louder.” Though “the argument following Katrina lacked any satisfying resolution,” he writes, “today we may be getting closer to answering questions about how a changing climate worsens hurricanes.”
Steven T. Corneliussen is Physics Today‘s media analyst. He has published op-eds in the Washington Post and other newspapers, has written for NASA’s history program, and was a science writer at a particle-accelerator laboratory.