Arctic Sea Ice: that 75% decline data

Tamino gives us a Sea Ice Update:

I’ve said it before and I’ll say it again: one of the strongest evidences of global warming is the dramatic loss of sea ice in the Arctic.

Read the original post for lots of data graphs, here’s just the conclusion which follows after Tamino patiently points out the distinctions between area/extent (which hit a record low in 2007) and volume (which hit a record low in 2011) and why volume is a more comprehensive measure (the thickness of ice coverage varies, volume takes this into account):

The summer minimum sea ice volume hasn’t just declined, it has decrease by 75% during the time span covered by the data:

a graph showing volume of Sea Ice on the y-axis and year on the x-axis: over the last 30 years the volume has declined from over 16 million km^3 to a around 4 million km^3 since 2010

It wasn’t that long ago that Anthony Watts made quite a fuss over claims that we had lost 75% of Arctic sea ice, calling the idea “ridiculous” and “patently false.” He was pretty thoroughly raked over the coals, because the statement was about summer minimum sea ice volume — which has declined by 76%. In my opinion, for Anthony Watts it’s the truth itself that is “ridiculous” and “patently false.”

A few more predictions: If this year’s minimum is higher than last year’s, then the fake skeptics will crow loud and long about “recovery” of the sea ice even though the trend remains undeniable. They have to take anything they can get — and when it comes to Arctic sea ice, they’re desperate. Anthony Watts will probably mention Mark Serreze from NSIDC and ridicule his notion of an Arctic sea ice “death spiral,” even though a death spiral is exactly what we’re witnessing.

If this year’s minimum is less than last year’s but doesn’t break the 2007 record, the fake skeptics will also talk about “recovery” and how there’s nothing to worry about.

If this year’s minimum does break the 2007 record, the fake skeptics will adopt one of two strategies. The dumber ones will talk about how it’s all because of something — wind, ocean currents, the Arctic oscillation, solar ultraviolet, leprechauns — anything except global warming. The smarter ones won’t breathe a word about it.

What will this summer bring? Will we break the record for the summer minimum again? In any of the measures? In all three? I don’t know. In addition to trend, sea ice shows fluctuations. The uncertainty in predictions is sizable. But this much you can expect: the trend will continue. Because of global warming.

I’ve said it before and I’ll say it again: those who deny that Arctic sea ice decline is powerful evidence of global warming aren’t skeptics. They’re fake skeptics.



Categories: culture wars, Science

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4 replies

  1. The really frightening thing about that (30 year) graph is that it covers a single generation. This means my children’s children really do have to hope for some significant change in the way their forebears (that would be us) live their lives.
    And you missed the other prediction: that this graph will be reworked over (whatever, but say) 500 years, so that this decline will seem like a mere blip.

  2. Yes, it’s the extrapolations of these trends that makes me understand the reflex nay-saying, somewhat (at least the initial impulse), of those who are saying that it just can’t possibly be happening. I don’t want it to be happening either. But it is.

  3. Only tangentially related, but I thought this article about the end of nature by Christopher Mims was a rather interesting read. His argument is that nature as we imagine it doesn’t really exist, as we basically run the world now and everything is part of our systems. Not sure if I completely agree with his assertion, but I find his writing style entertaining.
    h/t Not Exactly Rocket Science

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