Monday’s coverage of Pope Francis’ interview suggests climate change either led to or exacerbated recent hurricanes like Harvey and Irma. For instance, Reuters wrote, “Pope Francis said the recent spate of hurricanes should prompt people to understand that humanity will ‘go down’ if it does not address climate change and history will judge those who deny the science on its causes.”
The sources we analyzed weren’t forthright about the assumption. In other words, they juxtaposed climate change with the hurricanes, which is what can lead readers to connect the dots, but they didn’t explicitly state the connection between the two, so it could easily be accepted without question. Did climate change cause or exacerbate these hurricanes? Wouldn’t you know it — that’s the missing data in the media coverage of this story.
There are scientific arguments both for and against it. None of the articles we analyzed provided data against the correlation. Of the four articles, only BBC’s provided two arguments that could partly support the connection. It’s common knowledge that hurricanes form over warm ocean waters and they use warm, moist air. BBC explained that the hotter an atmosphere, the more moisture it holds (warm, moist air). And it cited an expert on the matter saying the Gulf of Mexico’s waters are roughly “1.5 degrees warmer above what they were from 1980–2010” (warm ocean waters). These conditions could explain why the hurricanes took on the magnitude they did, but they don’t answer the question, “Did climate change cause them?” The systems that surround hurricanes and their formation are complex, and it’s possible that they would have taken place regardless of climate change.
A 2014 National Climate Assessment by the U.S. Global Change Research Program said that “The intensity, frequency, and duration of North Atlantic hurricanes, as well as the frequency of the strongest (Category 4 and 5) hurricanes, have all increased since the early 1980s. The relative contributions of human and natural causes to these increases are still uncertain.”
It also said the recent increases in hurricane activity are in part linked to higher sea surface temperatures in the Atlantic, and that “numerous factors” influence those temperatures, including natural fluctuations, particulate pollution and manmade greenhouse gases. It said some studies suggest that natural variability “is the dominant cause of the warming trend in the Atlantic since the 1970s, while others argue that human-caused heat-trapping gases and particulate pollution are more important.”
The “Supporting Evidence” in the same 2014 report said, “The relative contributions of human and natural causes to increases [in North Atlantic hurricanes] are still uncertain.” It assigned a “low” confidence level to this statement, meaning there’s “Inconclusive evidence (limited sources, extrapolations, inconsistent findings, poor documentation and/or methods not tested, etc.), disagreement or lack of opinions among experts.”
It seems the jury’s still out on the subject, and this is an important point to not only bring to readers, but also to substantiate with data and scientific studies, rather than opinion. Our researchers found more data supporting various perspectives, which you can find in our Context section below.
Some scientists have already suggested there’s definitely a link. A recent op-ed in The Guardian by Michael Mann, professor of atmospheric science at Pennsylvania State University, calls it a “fact.” The headline reads, “It’s a fact: climate change made Hurricane Harvey more deadly.” Is it unscientific to suggest this is confirmed, given the inconclusive nature of the debate we explored above?
Considering that most of the world’s nations devote numerous and costly resources to climate change, it may be ill-advised to make these sorts of assumptions without first understanding the scientific basis for them. If the information isn’t available or conclusive, the media could encourage us to question the assumptions and think critically about the issue, rather than to accept it blindly.
Jens Erik Gould
Jens is a political, business and entertainment writer and editor who has reported from a dozen countries for media outlets including The New York Times, National Public Radio and Bloomberg News