By now, anyone paying attention has seen the headlines: this summer, unprecedented low levels of Arctic sea ice have broken all records for the satellite era.
The numbers have been jaw-dropping. With about 2 weeks remaining in the Arctic melt season, this year's sea ice extent is more than 1.8 million square kilometers lower than the levels we saw just six years ago, and nearly 700,000 square kilometers lower than what we saw in August during the previous record-melting year (2007).
And for the first 24 days of last month, that extent dropped an average of more than 95,000 square kilometers per day.
Remember - we probably haven't hit bottom yet. Unless something very unusual happens, we can still expect to see 2 (or more) weeks of melting in this season.
Jim Pettit's superb graphics show an Arctic which is clearly exhibiting a 'death spiral'. Below, see his depiction of the current Arctic sea ice extent, compared to past decade-long averages:
Sobering enough. But even more stunning is Pettit's graph of sea ice volume. Notice the slow (but consistently-downward) trend for the 1980s and 1990s, which grows much larger during the first decade of this century - and literally falls off a 'summertime cliff' in the last 3 years:
A good graphic is worth a million words - and Pettit shows the ice volume trend even more clearly below, where he graphs the percentage of each year's annual maximum that disappears during the annual summer melt season.
Once again, remember that we probably haven't seen the final numbers for 2012 yet:
Graphs like Pettit's are invaluable, because they convey so much information in a single image. But even the best graph does nothing to explain the effects that all this melting will have. And simply put, it's those effects that matter most to us.
So now that the media frenzy has cooled downed a bit, I think it's a good time to look very closely at those effects. Over the course of the next few weeks, I'll be publishing a series of articles to explain exactly why a melting Arctic is important to you - personally.
I'll look at the impacts that reduced Arctic sea ice will have on our own weather (and the impacts we can already see). I'll discuss how sea ice loss will unleash natural feedbacks, facilitating even more planetary warming. And I'll explain how the loss of Arctic ice (which has created a relatively stable climate throughout human civilization) will affect everything from agriculture to existing human settlements.
As a final note, I leave you with this image from Kinnard et al. 2011 - 1,450 years of summer Arctic sea ice extent. Just one more jaw-dropping graph in a season that leaves everyone watching this in shocked silence.