Four weeks of climate data:Arctic Circle Region #6

So far, we have had five slices of the Arctic Circle and every one has shown a warming trend over the time period 1955-2010. The last slice is polar Greenland, which excludes only a small part of the large island, a little in the south and the western part that counted in the previous polar region.

Greenland has a lot of land north of the Circle, but that land is extremely sparsely populated and very poorly covered by weather stations. There are seven grid points out of a possible 100 that give readings.

Looking at the Winter data, no trend is consistently upward, though the most recent time interval is clearly warmer than the last. The record warm Winter was about 30 years ago.

Spring also shows no trends. The null hypothesis for warming has to be "there is no warming" and the null hypothesis for an increasing trend has to be "there is no increasing trend". Both Winter and Spring data point to keeping the null hypothesis, or saying it in the technically proper statistical weasel words, "so far, we fail to reject the null hypothesis".

Greenland Summers say the same thing. The highs and lows bounce around the way random stat with no discernable trend would do.

Finally, a sign of a warming trend shows up in the low temperature pattern in Fall and in the median, just barely enough to overwhelm the data pattern we have seen.

We can say with just barely 95% confidence that the weather in Greenland is warming. Compared to the other five sections, the weather in Greenland appears to be relatively stable over this period, rising on average less than a full degree Celsius from the median reading of 1955-1975 to the most recent interval, 1999-2010.

Final Arctic tally

Warming regions: 6-0
Increasing trend regions: 2-4

A fair question is why Greenland is the odd region out in the Arctic. A big difference is a land mass with a very large ice cap. Bright colors like ice reflect heat and dark colors like sea water absorb it. This effect is called albedo. In Antarctica, a lot of the slices will be filled with ice covered land mass and some ice shelves above what would be open ocean if the ice weren't there.