On June 17, 2013, NASA's Terra Satellite captured a rare photograph of a clear view of Alaska. While the photo itself is beautiful, the reason for the nearly cloud-free sky has concerning implications for climate change.
NASA explains what caused the anomaly:
The same ridge of high pressure that cleared Alaska's skies also brought stifling temperatures to many areas accustomed to chilly June days. Talkeetna, a town about 100 miles north of Anchorage, saw temperatures reach 96°F (36°C) on June 17. Other towns in southern Alaska set all-time record highs, including Cordova, Valez, and Seward. The high temperatures also helped fuel wildfires and hastened the breakup of sea ice in the Chukchi Sea.
Phil Plait of Bad Astronomy finds the photo beautiful, but the implications of this shifting weather pattern "chilling":
A new study just came out possibly linking that Greenland system to global warming. It’s not a direct link; that is, it’s not that things are warmer now so we got more melting. What may be happening is that the changing climate is affecting the pattern of the jet stream, causing warmer high-pressure systems to sit and stay in one place in what’s called a blocking pattern.
In other words, weather patterns are changing because the climate is changing. The Arctic climate system in particular may be undergoing a rapid evolution due to changing conditions there; loss of sea ice (which exposes darker water, increasing the amount of heat absorbed from sunlight), the wobbling of the jet stream, and more subtle variations are playing havoc with the normal weather.
The first decade of this century was the warmest ever recorded. 2012 was the hottest year ever recorded. In early 2013, it was so hot in Australia that new colors had to be added to the heat map. And this summer in the US, we're experiencing a record-setting heat wave, wildfires and drought in the American West.
This is the new normal.
And the feedback loops being observed in Alaska and elsewhere in the Arctic are going to make climate change even worse if we don't act fast. As we noted with the case of eroding beaches in Malibu and Nantucket, waiting until the problem is right outside your door is too late.
You can see much larger versions of the photo at NASA's site.