Although the connection between global warming and natural disasters is not entirely clear, major hurricanes like Harvey and Irma — which hit the United States earlier this month — present a valuable opportunity to win over climate-change deniers, Yale experts say.

“Our climate is becoming more like that of a southern state,” said Jennifer Marlon, a research scientist for the Yale Program on Climate Change Communication. “But we can’t really detect that. There are windows of opportunity after disasters like Harvey and Irma. We have to use these times to help educate people so that they can make the connection that these really unusual events are unusual in part because of climate change.”

Still, climate change was not fully responsible for Harvey and Irma, Marlon said. Rather, she said, it intensified the storms by allowing moisture to build up in the atmosphere and causing water temperatures to spike. As a result, storm surges — an increase in sea level during a storm — became more severe, which led to an unprecedented 33 trillion gallons of rainfall in the case of Hurricane Harvey.

While some scientists argue that there is a significant relationship between climate change and natural disasters, others disagree, said Xuhui Lee, director of the Yale Center for Earth Observation. But either way, Lee said, the recent uptick in hurricanes has major implications.

“Regardless of whether or not hurricanes are tied to climate change, the fact is we’re going to have more climate extremes,” he said. “[Houston] is what they call a 100-year-storm [and] society [was] inherently not prepared. If you look at trends, it’s in the data.”

Angie Hanawa ’15 FES ’18, a research assistant for the YPCCC who analyzes climate change data, said that while climate change and freak weather incidents are connected, the relationship is not necessarily linear, adding that it is important to be careful about assuming causation.

“Hurricanes Harvey and Irma would have happened anyway, but their extent is definitely a result of climate change,” Hanawa said. “The challenge now is for the science community to communicate it in such a way that it resonates with people and isn’t just facts.”

Marlon echoed Hanawa’s sentiments, criticizing Environmental Protection Agency Administrator Scott Pruitt’s recent claim that climate change should not be a topic of conversation in the context of natural disasters such as hurricanes Harvey and Irma.

“Despite what Pruitt says, making that link for people, that [Hurricanes Harvey and Irma] are unusual in part because of climate change, is very important,” Marlon said.

She added that because the media does not prioritize climate change education, it is important for the science community to take the lead.

“If someone would clearly show the difference between what actually happened and what should have happened, that could do it,” Perry Leung FES ’19 said. “A simple graphic [about the hurricanes] that people could take home to see the delta of intensity, and then say to themselves, ‘Now I can understand why climate change matters.’”

The aftermath of hurricanes Harvey and Irma presents a fleeting opportunity to acknowledge the role that climate change plays, Leung said. Hurricanes are shocking and can cause a climate-change nonbeliever to reconsider. By contrast, he said, a sunny day in September won’t do much, because people treat it like nothing more than an “extra day of summer.”

John Gross |  johnny.gross@yale.edu