It may be tempting to attribute current weather trends like the record warmth and early rains on climate change caused by humans.
But KPLU weather expert Cliff Mass says a newly-published paper should give us pause. It shows that the global warming of approximately 1 degree Celsius on the U.S. West Coast since 1900 appears more likely to be the result of natural variations than of human inputs of greenhouse gases.
“A very, very important study,” Mass said of the publication in PNAS by doctors James A. Johnstone and Nathan A. Mantua, which analyzed the temperature trend over the West Coast during the last 100 years.
“And what they found is that the temperature variations were driven by changes in pressure, in winds, in circulation, and not driven by greenhouse-gas warming,” Mass said.
But Mass said it’s also important to note that the authors said this doesn’t mean that global warming is something we don’t have to worry about.
“It’s just that here in the western United States, the temperature changes are relatively weak from global warming due to the Pacific ocean. And natural variability is still very large, compared to that,”Mass said. “By the end of this century, we do expect the global warming signal from greenhouse gases to be important. But what their study indicates is not yet.”
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The weekly KPLU feature "Weather with Cliff Mass" airs every Friday at 9 a.m. immediately following BirdNote, and twice on Friday afternoons during All Things Considered. The feature is hosted by KPLU Environment Reporter Bellamy Pailthorp. Cliff Mass is a University of Washington Professor of Atmospheric Sciences, a renowned Seattle weather prognosticator, and a popular weather blogger. You can also subscribe to a podcast of “Weather with Cliff Mass” shows.
