You’re on thin ice, sunshine

Here’s something to disquieten your day.  The National Oceanic and Atmospheric Administration, a scientific agency within the US Government who do some very respectable work on climate, released this video recently showing the ages of different parts of Arctic ice over the last 27 years.  The whiter the ice, the older it is.  Make sure you watch it to the end.

You can see from the very dark blue that there’s still a wide area covered with ice, even at the end of Summer.  However, what’s less obvious is that this ice is thinning.  As that happens, that which has been buried deep for decades becomes exposed and melts.  News ‘articles’ like this love to point out that the 2013 coverage area was greater than the previous year (2012 took the trophy for lowest sea ice minimum on record).  To anyone who is inclined to believe the Daily Mail, I recommend looking up the phenomenon of regression to the mean.

Maybe this illustrates what I’m trying to get at more clearly:

We’re looking at an ice-free Summer Arctic within a decade.  When this happens, the climate takes a turn for the worse; Arctic sea ice – a shiny white surface covering a vast area of the planet – does an excellent job of reflecting the Sun’s intensity back into space.  When’s it’s gone during Summer months, the dark ocean absorbs the energy much more readily, accelerating the climatic warming process.  This is a well-understood ‘positive feedback’ effect, though there’s nothing positive about it.  It’s because of phenomena like this (and others) that climate scientists are increasingly worried about ‘runaway’ global warming; we face a tipping point some time in the future, where warming triggers these feedbacks and we end up with a temperature increase much greater than the 2 degrees many are trying desparately to avoid.

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