Despite skepticism, UC scientists affirm link between extreme weather and climate change

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As Hurricane Harvey surged over Houston last week, killing at least 70 people and displacing tens of thousands, scientists and activists were quick to point to climate change as a potential contributor to Harvey’s staggering strength.

Further evidence of climate change-induced extreme weather seemed to be on display over the weekend and into this week as temperatures soared in the Bay Area. The Berkeley Hills reached 105 degrees Friday afternoon as the city opened 11 cooling centers to let residents escape the heat.

Hurricane Irma plowed over the Caribbean on Wednesday, causing two deaths on French-controlled islands and threatening to damage Puerto Rico’s fragile power grid so profoundly that parts of the island could lose power for months, according to the New York Times.

“Everything about (Harvey) is consistent with the predictions of climate science,” said Daniel Kammen, a former science envoy for the U.S. Department of State and a campus professor in the Energy and Resources Group, in an email.

Paul Ullrich, a UC Davis professor who studies climate change and extreme weather, said no single extreme weather event could be attributed directly to climate change. The severity of hurricanes such as Harvey and Irma — or heat waves such as the Bay Area’s — is impacted by climate change, he added.

Basic physics and chemistry, Ullrich said, dictate that warmer air holds more moisture and that more moisture means more intense storms. He also said even small increases in global temperatures make extreme weather events much more likely to occur.

It’s very difficult to attribute any specific event to climate change,” Ullrich said, “but we can certainly see fingerprints of the climate influence on extreme weather events.”

Some conservative commentators have criticized drawing an explicit link between climate change and extreme weather events, arguing that discussion should focus on relief efforts rather than climate policy.

Conservative talk show host Rush Limbaugh suggested Tuesday that forecasts for Irma had a liberal bent to inspire public outcry and rally support to fight climate change. Michael Graham, another conservative talk show host, said many reactions to Harvey were meant to bash President Donald Trump and act as a facade to push stronger economic regulation.

“They see the hurricane, and while people are still swimming and climbing into boats, they’re screaming and yelling about (climate change) because they see an opportunity,” Graham said. “It’s classic political opportunism.”

Chris Janssen, a campus senior and Houston native, has little patience for Limbaugh and Graham’s arguments. Swaths of Janssen’s neighborhood flooded during Harvey, and many of his friends and neighbors’ homes sustained damage.

Janssen, a molecular and environmental biology major in the College of Natural Resources, said that after Harvey, climate change mitigation should be an important policy priority and that denying climate change is “intellectually dishonest.”

“The idea that (weather forecasts) are bad when they predict something we don’t want to happen or because it’s something that would require us to change is just absurd,” Janssen said. “It’s very, very frustrating, especially as someone who’s concerned about climate change and the future of our planet.”

Contact Simon Greenhill at [email protected] and follow him on Twitter at @simondgreenhill.