Wednesday, December 02, 2009

RealClimate - [Absolutely remarkable statement by Gavin Schmidt]
Gavin [Schmidt],

In your opinion, what percentage of global warming is due to human causes vs. natural causes?

[Response: Over the last 40 or so years, natural drivers would have caused cooling, and so the warming there has been (and some) is caused by a combination of human drivers and some degree of internal variability. I would judge the maximum amplitude of the internal variability to be roughly 0.1 deg C over that time period, and so given the warming of ~0.5 deg C, I'd say somewhere between 80 to 120% of the warming. Slightly larger range if you want a large range for the internal stuff. - gavin]
[Flashback: If Schmidt thinks natural variability should have been only .1 C in 40 years, how can we explain this 2.2 C change in 36 years?]
[David Archibald] What is also interesting is the 2.2° temperature rise from 7.8° in 1696 to 10.0° in 1732. This is a 2.2° rise is 36 years [in Central England]. By comparison, the world has seen a 0.6° rise over the 100 years of the 20th century. That temperature rise in the early 18th century was four times as large and three times as fast as the rise in the 20th century.

The significance of this is that the world can experience very rapid temperature swings all due to natural causes. The temperature peak of 10° in 1732 wasn’t reached again until 1947.
Clive Spash resigns from CSIRO after climate report 'censorship' | Herald Sun
SCIENTIST Clive Spash has resigned from the CSIRO and called for a Senate inquiry into the science body following the censorship of his controversial report into emissions trading.
[Look at what's currently displayed at the top of Joe Romm's blog] « Climate Progress
“The Web's most influential climate-change blogger” — Time Magazine

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