Why is Arctic sea ice extent important?
August 26th, 2010 by Jim JustA good friend recently asked me why I give so much attention to news about Arctic sea ice extent at this blog, saying he just glosses over posts on this subject.
Here’s the reason: the area of sea ice cover is an important, amplifying climate feedback. Loss of sea ice is a cause of concern because as the area of ice decreases, increased absorption of sunlight by the darker ocean causes more sea ice melting. As this graph from Makiko Sato & James Hansen’s new blog shows, Arctic sea ice extent has been declining steadily . . .
. . . as has sea ice volume. What ice remains is getting thinner.
It’s not just sea ice that is melting. Ice sheets are shrinking too, both in Greenland and in Antarctica.
And the ice loss over the last few years has been at a time of minimum solar irradiance. Solar irradiance is now once again on the upswing.
It seems likely that September Arctic sea ice may be all but gone within a few decades – or perhaps even sooner. What does less Arctic sea ice mean for Earth’s weather patterns?
NASA is predicting loss of summer sea ice will mean more severe winter storms in the northern hemisphere – a prediction which is already being borne out.
Following Arctic sea ice extent is fascinating because it shows that global warming is not something to worry about in the future. Global warming is here and now, and is already affecting us in our daily lives. What’s worrisome is that the impacts will only get more severe. By the time the impacts are bad enough to get our attention, it will be too late – the damage will already have been done. Under the best-case scenario it will take Earth a thousand years or more to recover. Under the worst-case scenario, Earth will flip into a different, stable climate regime which won’t be hospitable to human existence.