It's been freakin' cold this spring of 2012 in the Great Pacific Northwest. Also, rainy. March saw the most rainfall ever in Portland. I think here in Salem we had the third rainiest March on record.
Today I went for an afternoon dog walk in 45 degree weather. Driving home from my Tai Chi class tonight, my car thermometer "dinged" with a 37 degrees nearing-freezing alert.
Global warming deniers seize upon any unusual cold spell as evidence that Al Gore is wrong; global warming is a fraud perpetrated by the United Nations One World Order and complicit climatologists; weird record-breaking weather is just doing what the weather does -- be changeable.
Here's the scientific truth: "Arctic Warming Favors Extreme Prolonged Weather Events 'Such as Drought, Flooding, Cold Spells, and Heat Waves."
By showing that Arctic climate change is no longer just a problem for the polar bear, a new study may finally dispel the view that what happens in the Arctic, stays in the Arctic.
The study, by Jennifer Francis of Rutgers University and Stephen Vavrus of the University of Wisconsin-Madison, ties rapid Arctic climate change to high-impact, extreme weather events in the U.S. and Europe.
The study shows that by changing the temperature balance between the Arctic and mid-latitudes, rapid Arctic warming is altering the course of the jet stream, which steers weather systems from west to east around the hemisphere. The Arctic has been warming about twice as fast as the rest of the Northern Hemisphere, due to a combination of human emissions of greenhouse gases and unique feedbacks built into the Arctic climate system.
The jet stream, the study says, is becoming “wavier,” with steeper troughs and higher ridges. Weather systems are progressing more slowly, raising the chances for long-duration extreme events, like droughts, floods, and heat waves.
...In addition, the study also mentions jet stream configurations that led to heavy snows in the Northeast and Europe during recent winters. Such events are also “consistent” with the study’s findings, according to the paper.
A map included with the blog post shows why our relatives in the mid-West have been gloating about marvelous warm weather this spring (close to 80 degrees, or even above, I believe), while we've been telling them "it's still cold and rainy Oregon."
Surface temperature departures from average during the March heat wave. Credit: NOAA/ESRL.
Blue colors are colder than average in March 2012. Darker the blue, the more from the long-term average. Red, orange, yellow, and green show March temperatures warmer than average, with red, orange, and yellow being the warmest.
So most of the United States has been basking while the West Coast states have been "enjoying" (if that's the right word, which to me, it isn't) cooler than normal temperatures. Note that western Oregon and Washington had the largest deviation in the cool direction of anywhere in the U.S.
Lucky us. But the weather will change. That's what weather does.
However, with global warming becoming steadily stronger, this study says that as the Arctic warms faster than the world as a whole, changes in the jet stream are going to cause even weirder weather in the future.
The study contains a stark warning about future weather patterns, given projections showing that Arctic climate change is likely to accelerate in coming years. “As the Arctic sea ice cover continues to disappear and the snow cover melts ever earlier over vast regions of Eurasia and North America, it is expected that large-scale circulation patterns throughout the northern hemisphere will become increasingly influenced by Arctic amplification,” the study reports.
In other words, rapid Arctic warming is expected to exert a growing influence on the weather far beyond the Arctic Circle, for many years to come.