Scientific predictions, observations, and climate models all lead to the conclusion that signs and effects of global warming will be most extreme near the north pole. I saw some data this morning that made me sit up and take notice.
We are now in the middle of the most rapid sea ice melt of the year. That's not the news. The news is that the most recent data from NASA satellites and the National Snow and Ice Data Center (nsidc.org) show a notable drop in the percentage of the Arctic Ocean and nearby waters over the past few days.
Now a few days do not a trend make, but it is worth keeping an eye on!
This map (courtesy nsidc.org) shows two things. 1) It shows orange lines that indicate the historical average limit of sea ice cover in the Arctic Ocean between 1979 and 2000 for this date, and 2) the white area shows the actual sea ice cover for this date.
Just in case nsidc.org isn't one of your favorite web sites, and you don't routinely follow what's going on in the Arctic (I mean, what normal person does?), here's the scoop. During the winter of 2011-12 there was a larger than average coverage of sea ice in the Bering Sea (west of Alaska and north of the Aleutian Islands) and it hung around longer than usual. Today's map shows that the Bering Sea ice is breaking up - FAST! Also, there is quite a bit of open water showing up north of central Canada and central Russia. So, why the big news?
If you take a look at the graph below (also courtesy of nsidc.org), you will see the historical average amount of sea ice cover (1979-2000 - dark gray line), the area containing 95% of all historical observations (1979-2000), the current extent of sea ice cover for 2012 (blue line), and the extent of sea ice cover in 2007 - the year we observed the lowest sea ice extent ever (green dashed line).
The sea ice cover for 2012 fell easily within the normal range for historical sea ice cover all spring...until now. During the past few days the sea ice extent has dropped out of the average range, and even below the 2007 extent.
Does this mean we will see record sea ice melt in the Arctic this year? There's no way to tell at this point, because wind and weather conditions work together to determine the rate of ice melt and where the ice is blown. But, these data show that we should keep an eye on the Arctic. Why? The overall sea ice cover has taken a short-term dip in total cover. That may be temporary or it may be the beginning of a rapid melt. Only time will tell on that one.
Why do I follow what's happening in the Arctic Ocean? The Arctic is the Earth's climate "Canary in a Coal Mine". Coal miners used to take canaries with them into the mines. As long as the canaries sang and were healthy, they knew the air was OK. But when a canary keeled over, passing out or dying, the miners knew it was time to get out. This is because the canaries were more sensitive to air quality changes than humans. Similarly, the Arctic is more sensitive to climate change than other areas of the globe, so when we see changes there - and we ARE seeing changes there, it's time to take notice and make changes to mitigate the problem.
What changes are we seeing? For one, both winter and summer sea ice cover in the Arctic has been dropping significantly for the past 30+ years!
By the way, if noise in the data concerns you, you need to realize that EVERY natural system contains noise in the data. This includes everything from local and global average temperatures to your own heart rate. But if you collect data long enough, and scientists have, trends, if they exist in the data, will become apparent. The trend in the Arctic is that it is getting warmer up there, and as a result the sea ice cover is dropping year to year.
In other words, the canaries are having a hard time singing. They may be having a hard time breathing.
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