Pesky Reality Intrudes in Denierville (again). Danish Ice Maps from the 30s.

April 11, 2013

1938_08a

I bumped into some of these sea ice maps squirreled away on a dusty corner of my HD,  on my way to researching this week’s video,   and it occurred to me this would make a good post. Checking around, I see Neven already had it covered some time ago. 

Nevertheless, people should know about these very valuable historical documents – Danish Sea Ice Maps from the early 20th Century.

From Arctic Sea Ice Blog:

I’m supposed to be on a holiday and should let this one slide, but it’s too much. I was expecting fake skeptics to remain mostly silent in face of the ice massacre up north, but apparently they acutely sense how big this blow is to the remaining shred of their credibility, and so they upped the ante of misleading and distorting stupidity. Anyone can see and judge the silliness of paid shill Marc Morano, 5-sentence posts regurgitator/vomiter Steve Goddard and of course WUWT. But this Sunday Times article, written by well-known pseudo-journalist Jonathan Leake (search for his name on Deltoid) had a quote by presumed scientist John Christy that really got my hackles up:

Professor John Christy director of the Earth System Science Centre at the University of Alabama in Huntsville, said the Arctic had indeed warmed, but there was also anecdotal and other evidence suggesting similar melts from 1938-43 and on other occasions.

“Climate change is a murky science”, he said. “To some it’s an easy answer to say it’s due to extra green house gasses. To the rest of us, separating natural variability from human impacts remains a wicked problem.”

Commenters over at Skeptical Science quickly took this nonsense apart. First FrankD:

Danske Meteorologiske Institut published a series of annual reports on arctic sea ice covering most years from 1893 to 1956. The link has one folder per year, with each containing individual pages (month identified by the trailing digit) and the whole annual report (about 5 meg each).

Just referring to August extent…

Its true that ice extent was lower in the 1930s than it had been in the preceding 30 years. In particular, 1938 saw a dramatic reduction from the previous years – it was probably 1.4 M km^2 below the then long term average and maybe 0.6 M km^2 below the already low years in the late 30’s (carefully measured using Eyeball, Mk I).

So, it is fair to say there were some big melts in the 30’s. But Christy’s false equivalence is an epic fail – “similar melts” is pretty nice weasel-wording for mine. 1.4 M km^2 below recent climatology? Considered like that, 1938 was like 2010, I guess.

But in absolute terms, August 1938 extent was much greater (4 M km^2?) than today. So any attempt to conflate the two is…well…I can[‘t think of an adjective suitable for polite company.

Taking the Kinnard graphic (below) – the 1930’s “similar melt” is the second last dip on the graph, the first decline with modern observational data. This saw a return to “normal” after a peak that had seen the greatest extents in 500 years.

kinnard

Compared to the current decline on Kinnard (even without “enhancement”)? Well, even on Sesame Street they could tell you when one of these things was not like the other…

And then Daniel Bailey posted these two graphs:

(ABOVE)Arctic Sea Ice Extent August 1938.

(BELOW)

Arctic Sea Ice Extent August 2012:

My question to Dr. Christy: Why do you lie?

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44 Responses to “Pesky Reality Intrudes in Denierville (again). Danish Ice Maps from the 30s.”

  1. MorinMoss Says:

    Peter,
    Between this post and the ones that follow, you have a few on the Arctic and Greenland.
    I thought you’d be interested in one I came upon regarding Arctic methane. I’ve been hearing more and more about it in the last few years and the experts are increasingly worried.
    Here’s a 20-min clip featuring Peter Wadhams, James Hansen, David Wasdell and Natalia Shakhova


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