While I have been venturing South and East, the Arctic regions have been a enjoying a mild end to their long winter.
One way to quantify this is to use satellite imagery to measure the extent (in millions of square kilometres) of the area of sea which contains at least 15% of Sea Ice. This figure is called Sea Ice Extent.
When the sea and air are cold, Sea Ice grows quickly and extends over a large area. So this relatively simple measurement provides a ‘proxy’ measure for the severity of the Arctic Winter.
Fortunately we have a continuous record since 1979 and the graph at the head of the page shows this years data in context.
Although the freeze is not quite (it usually ends around the Equinox on March 21st), it looks like the extent of Arctic Sea is the lowest it has been at this time of year – at least since 1979.
This is consistent with the long-term trend which has seen the Maximum Extent of Sea Ice shrink by approximately 40,000 square kilometres per year on average.
This is only half the long-term trend in the Minimum Extent of Sea Ice which occurs every September. This has been shrinking by approximately 83,000 square kilometres per year on average.
Using just a linear extrapolation, we would expect the entire Arctic ocean to be free of Sea Ice in September in just 60 years – by 2076. However there many reasons to expect this to happen much faster.
Personally, I expect see the Arctic ‘ice-free’ in summer in my lifetime, which I am anticipating will end in 2040 at the age of 80.
It is worth noting that the record low extent of the winter freeze is not necessarily an indicator that the summer melt will also reach a record low extent. The US National Snow and Ice Data Centre have an excellent discussion of these issues and many more here.
P.S. Whew: All that and still I managed to avoid the use of the phrase minumum maximum!