A tragic, devastating, and mostly ignored in the media, loss of Arctic sea ice is still ongoing. Today, sea ice area fell below the threshold of 2.3 million square kilometers to touch 2.29 million square kilometers today. By comparison, the total land area of Greenland is about 2.1 million square kilometers. Sea ice extent also fell again today reaching 3.59 million square kilometers and breaking the threshold of 3.6 million square kilometers.
The record retreat this year has extended the vast losses seen in 2007. Now, it appears there is dire risk of losing the Arctic ice, its related habitats, and the cooling services it provides. This will have a number of very powerful impacts, not the least of which is economic. A Pew Study recently estimated that added cooling costs alone resulting from the loss of Arctic sea ice could total between 4.8 and 91.3 trillion dollars by 2100. The fact that this study was based on model estimates for sea ice area, which have tended to vastly lag observations, means that the lower range of estimates is far too conservative. Other impacts include far less predictable weather, enhanced Greenland melt, and a potentially devastating erosion of seasonal variability.
With much of the energy from sea ice melt now transferring to the land-bound ice sheets of Greenland and, to a lesser extent, Antarctica, we can expect weather patterns that result in rapidly increasing melt in these regions.
James Hansen has identified a problem in ice melt forecasting. The question involves Greenland’s ice melt’s rate of doubling. Hansen notes that melt rate could double every ten years or as quickly as once every six years. Either melt rate doubling is severe. But a six year doubling rate would have a terrible impact on sea level rise. Likely, even the doubling rates don’t paint the whole picture, with large single melt pulses increasingly likely as heat builds in the region of Greenland.
Recently, changing weather patterns have enhanced melt over Greenland. A discussion of these weather patterns can be found here. Simply put, a strong high pressure system has tended, with greater and greater frequency, to form over Greenland. These events have coincided, in many cases, with large melt events and may well be an emerging pattern of atmospheric heat transfer to the frozen island. Here is a weather map illustrating the pattern in a three decade trend:
Areas of high pressure are indicated in green, yellow and red. Areas of low pressure are indicated in blue and purple. Since 2007, this pattern has been emerging with particular strength.
It is likely that ice loss is a major contributor to the emergence of this new weather pattern.
For this year, record values for sea ice loss show alarming departures from previous records set in 2007 and 2011. Departure values for 2012 are as follows (previous record year in parenthesis):
JAXA Extent: -655,000 square kilometers (2007)
Cryosphere Today Area: -607,000 square kilometers (2011)
PIOMAS Volume: -400 cubic kilometers (2011)
NSIDC Extent: -682,000 square kilometers (2007)
Now all major values for sea ice area and extent are more than 600,000 square kilometers below previous records. Percent losses from the previous record low are: JAXA 15.4%, Cryosphere Today 20.5%, NSIDC 16.3%. For a single year, this is a very high rate of loss. September 15 marks the melt season’s average end date and we are still one week away. However, highly variable Arctic weather has resulted in melt seasons over the past 30 years ending any time from late August to early October.
If you are concerned about the Arctic and wish to put pressure on governments and businesses to protect this key environment, you may be interested in the following petitions:
Though these petitions are helpful measures, any chance of saving the Arctic from total loss of sea ice within the next generation will require a massive cessation in the use of fossil fuels and, likely, the application of a number of technologies that actively remove carbon from the atmosphere. That is the situation we are now faced with. And we need to raise awareness as rapidly as possible or face even more devastating consequences.