A Tale of Two Poles
Posted on Oct 02, 2012 in Opinion
The Arctic ice melt has halted – for now. On September 16th, the record decline in the frozen mass constituting our planet’s “attic” reached a low of 3.41 million square kilometers. This figure roughly translates into 43 percent the size of the contiguous United States. What’s so alarming about this extent of ice loss over the past several decades is that it is unmatched in at least the past 1,450 years. We might have to go back to 4,000 B.C. to observe such a minimal amount of ice present across the Arctic region.
The rate of thaw has been 12 percent each decade, which is worse than even the grimmest scenario that scientists laid out in the 2007 report by the Intergovernmental Panel on Climate Change. The current model variance for an ice-free Arctic ranges from 30 years to a mere four years from present day. The general consensus of model agreement, though, tends to be at least 10 years.
Yet, with unpredictability being a hallmark of climate change, a more rapidly deteriorating melt should probably be anticipated.
And for more ennui, this year marks the fifth straight time that ice-free navigation has been possible along both the coasts of Canada and Russia. Some scientist believe that in a few decades, ice-free navigation across the Arctic Ocean may be possible in the month of August.
Unless you happen to work for a global transport company or have a strong desire to begin exploratory drilling in the Arctic, you should be concerned about this news. Besides the previously reported sea level rise and release of carbon and methane into the atmosphere, there are other effects that will require our attention.
One major repercussion is on the jet stream, which is a quick-flowing current of air that serves as a demarcation line between different air masses. The less ice cover means that more of the sun’s heat will be absorbed by the darker-colored ocean, which in turn will prompt more warm and moist air to enter the atmosphere, leading to changes in the stream patterns. These disturbances in a naturally occurring jet stream are evident in the fall and winter, where an over-amplified stream can result in extreme weather events, such as record cold snaps or severe storms.
One other bit of recent news is the meager long-term growth of Antarctic sea ice, despite the fact that the waters around the continent are warming at record rates. How can this be? One would imagine that as ocean temperatures rise, scientist would observe a shrinking ice mass.
The answer has to do with stratification. The Southern Ocean has both a layer of cold water near the surface and a warmer sector at a deeper level. As the general rule goes, warm water rises, leading to ice melt near the surface. As the disintegration continues, there is an increase in air temperatures, which triggers more snow and rain to fall. The added precipitation causes the cold surface layer of the ocean to become less dense and more stratified, or separated, from the warmer water below. Since less mixing of the two layers occurs, less warm water rises to the surface. The result is less sea ice lost – in the short term, though. As the world continues to warm, the water will be unable to support such an abundance of ice, and more thawing will ensue.
Clearly, the phenomena in the Arctic and the Antarctic yet again demonstrate the fragile lattice that is our planet. And that lattice is breaking.