SEATTLE – Thirty years ago this week, NASA climate expert James Hansen gave groundbreaking testimony before Congress. He told them that human-caused global warming was already happening.
Time has proved him right, according to a new analysis of National Oceanic and Atmospheric Administration data by The Associated Press .
The average yearly temperature in the continental U.S. is nearly 1.6 degrees warmer today than it was 30 years ago, the analysis shows. In that period, the average yearly temperature has increased by more than 1 degree in all but one state.
The lone exception? Washington. Temperatures have gone up here, too, in the past 30 years, but by only a little more than half a degree. Oregon had the second-smallest increase, at just more than 1 degree, and North Dakota’s was third.
Alaska has had the most dramatic temperature change, a jump of about 2.4 degrees. After Alaska, Vermont and New Jersey warmed the most, in that order.
In the Lower 48 states, there are 344 NOAA climate divisions – these are groupings of counties that have similar weather. All of them have experienced warming in the past 30 years. But the six climate divisions with the smallest increases are all in Washington (the state has a total of 10 climate divisions).
The AP data also includes 188 cities, with three in Washington. In Olympia, the temperature has gone up by a little more than half a degree. Seattle’s average yearly temperature has increased about 1 degree. Yakima, though, has shot up by about 3 degrees, which is among the highest increases nationally.
So we’ve enjoyed relatively normal temperatures here recently, compared to the rest of the country – but how meaningful is it in terms of climate change?
I asked a couple of experts what they make of Washington’s smallest-in-the-nation temperature increase these past 30 years.
“I wouldn’t put too much significance to it,” said Nick Bond, associate professor of atmospheric sciences at the University of Washington. “From a climate perspective, 30 years is a short time for a trend.”
He said that if you looked at the temperature over a longer period, Washington probably wouldn’t look like such an outlier. The 30-year period starts in the 1980s, which was a warmer than average cycle for Washington.
“You’re starting at a relatively warm time, so you’re not going to get as big of a change as if you started at a relatively cold time,” he said.
Even so, Bond said he’s not surprised that Washington’s climate hasn’t warmed quite as much as other states in the past 30 years.
Climate models show that along the Pacific Coast, there’s a somewhat slower warming trend, he said. That’s because of the moderating influence of the ocean – and the prevailing winds here come from the west, off the ocean.
“The oceans are absorbing most of the heat from the higher concentration of greenhouse gases,” Bond said. “But the heat capacity of the ocean is so large, it still hasn’t warmed up as much as land areas.”
Bond said the trend is probably going to continue, with a more muted warming along the West Coast compared with the inland areas of the country.
“Those trends are inexorable. The climate is changing,” he said.
Kathie Dello, associate director of the Oregon Climate Change Research Institute, said that it doesn’t matter if we’ve warmed less than Florida or some other state. The bottom line is that we’ve warmed, and the impacts of it are visible.
“The Pacific Northwest has warmed about 2 degrees over the recorded past, 1895 to 2016,” Dello said in an email, “and we know we are responsible for this warming.
“Hot and dry summers have given us some of our biggest wildfire years. Warm winters make for lousy ski years and summertime water shortages. This is all happening here and now.”
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