Arctic Sea Ice Extent Has Reached a Record Low

Arctic sea ice extent over time. Image: Japan Aerospace Exploration Agency.

Yesterday (August 27th), the National Snow and Ice Data Centre announced that the extent of Arctic ice had reached a new record low.  And we are still weeks away from the end of the Arctic ice’s melting season.  This is yet another clear indicator that our planet is warming.  The previous record low was set in 2007, with 2011 in 2nd place and 2008 in 3rd.

The loss of Arctic ice is happening much faster than scientists had previously projected.  In the IPCC’s 2007 Fourth Assessment Report, it was believed that we would see an ice-free Arctic by the end of the century.  Now it is believed that this will occur by 2030!

A comparison of Arctic ice extent. Top is September 1979, bottom is September 2007. Images: NASA.

The loss of Arctic sea ice has many important consequences for the planet and everything that lives on it.  Arguably the most important of these consequences is the acceleration of global warming.  Arctic ice reflects sunlight and sends it back into space.  But as the ice shrinks, it exposes the dark water below, which absorbs sunlight.  The more the ice melts, the more sea is exposed, the warmer the sea (and the rest of the planet) gets.  The loss of Arctic sea ice is what is known as a “positive feedback” to global warming: the more it happens, the warmer the planet gets.

The ice reflects sunlight while the dark ocean absorbs it. Image: Climate Progress.

Rapid loss of Arctic sea ice could also affect another positive feedback of global warming: the melting of the world’s permafrost (land that, in the past, remained frozen all year long).  As the Arctic Ocean warms, it could lead to a more rapid melting of the permafrost.  As the permafrost melts, it will gradually release the carbon that it holds, increasing the greenhouse effect and warming our planet.  Unfortunately, the world’s permafrost holds four times more carbon than we have emitted through the burning of fossil fuels.  So, this is potentially a very big problem.

Warming of the Arctic Ocean will also exacerbate sea level rise.  The melting of Arctic ice does not directly contribute to sea level rise because it is floating on the Arctic Ocean.  (This is contrary to Antarctic (south pole) ice which sits on top of the Antarctic continent).  However, more heat in the Arctic Ocean will lead to more rapid melting of glaciers on Greenland and northern Canada.  Melt water from those glaciers will make its way to the oceans, raising their levels.  We are pretty much guaranteed a sea level rise of at least one meter by the end of the century, but it could be worse if we do not get our emissions under control ASAP.

Loss of Arctic sea ice could also lead to a more man-made positive feedback.  As the Arctic Ocean opens up, oil and gas companies are “chomping at the bit” to go and dig up any oil and gas that may be found beneath that ocean’s floor.  As those fossil fuels are extracted, they will mostly be burned as a source of energy, adding more carbon to the atmosphere, increasing the greenhouse effect and warming our planet that much more. (Not to mention the potential disasters that could occur from exploring for oil and gas in such isolated and dangerous waters.)

Finally, the loss of Arctic sea ice is a more direct threat to the people and animals that depend on it for their survival.  Large animals who live in the Arctic hunt or give birth on the Arctic ice.  Also, many human populations still hunt and make a living on there.

Polar bears are among the large animals that depend on the Arctic ice sheet. Image: US Fish and Wildlife Service.

And who knows what Santa will do…

But, seriously.  Nature has given us yet another warning that our planet is warming and our climate is becoming unstable.  We either heed that warning or face the consequences.  I hope we will do the former rather than the latter.