"We found about 1 in every 8 decades has near-zero or negative global temperature trends in simulations which would otherwise warm at expected present-day rates. Given that we have seen fairly consistent global warming since the 1970s, these odds suggest the observed slowdown was due to occur."Two questions:
1. Does anyone want to point out the flaw in the statistical reasoning? (Hint: Boulder hasn't had 100 year flood since 1896, we must be now overdue!)
2. Can anyone point to a prediction of a slowdown in temperature increase made before the slowdown occurred?
7 comments:
That is an amazing comment from someone claiming to be a scientist. It's like saying that having thrown a dice 10 times and failed to get a six, the chances are high that the next throw will give a six!
Of course, what they 'found' was based on their computer model.
Back in the real world, there have indeed been periods when the 10-year trend has been near to zero, but these have followed major volcanic eruptions (most recently Pinatubo).
See
http://globalwarmingquestions.googlepages.com/trendvolc.jpg
and Lucia's article
http://rankexploits.com/musings/2009/how-to-obfuscate-forget-to-mention-volcanoes/
for related discussion of an equally flawed paper by Easterling and Wehner
Given that we have seen fairly consistent global warming since the 1970s, these odds suggest the observed slowdown was due to occur."
Gosh... could it mean the variability of 8 year trends in these particular model runs exceeds that of the earth's climate? Some models have very wild temperature variations.
Also, what happened to the observation that we have had 8 year negative trends since the 70s? (All are associated with periods of volcanic eruptions. Those happened frequently. So even if someone had the theory we were "due", how would they know?
To be fair maybe they are saying that the underlying natural variation seems to be cyclic and that mention of odds was just a slip. I'd prefer that excuse to the recently-seen "the model sometimes goes down too" excuse which combines poor knowledge of numerical methods with a childlike "my randomness is as good as yours" joke.
Roger, this may be of interest:
http://devoidofnulls.wordpress.com/2009/09/07/144-month-trend-in-observations/
Bizarre discussion on BBC radio 4 this morning: apparantly Latif of Kiel is "predicting" that we may see a "flattening off" of the "remorseless rise in temperatures" at some point "in the near future". No recognition of the past decade then.
See http://news.bbc.co.uk/today/hi/today/newsid_8258000/8258167.stm and look at 0714.
A small point:
According to HadCRU, global temperatures experience roughly ZERO increase from the mid 1930s to the mid 1970s. That's four decades.
More than 100% of the net warming of the last 70+ years occurred during a 22 year window ending in the 1998 El Nino.
Even if it were established that in one out of eight decades, there should be no material increase in temperature, that's not what we are looking at. We are looking at a planet which, most of the time, is not showing the signs of global warming.
Alarmists could reasonably claim that due to natural climate variations that we don't yet understand, global temperature shows a sort of punctuated equilibrium, with most warming happening over brief, concentrated, periods of time.
I would guess that they are not saying this because:
1. They would have to acknowledge not actually being able to model the climate system.
2. If true, it would significantly reduce estimates of climate sensitivity.
In my opinion, both #1 and #2 are clearly true (although punctuated equilibrium may or may not be) and denying them only damages the case for action, which could certainly still be made.
Climate science is so feather-light - when the climate is warming we get predictions of more warming, when it's not warming, we get predictions of more non-warming or cooling.
Can anyone point to a prediction of a slowdown in temperature increase made before the slowdown occurred?
Landscheidt T. (2003): New Little Ice Age Instead of Global Warming? Energy & Environment, Volume 14, Numbers 2-3, 1 May 2003 , pp. 327-350(24)
Outlook:
“We need not wait until 2030 to see whether the forecast of the next deep Gleissberg minimum is correct. A declining trend in solar activity and global temperature should become manifest long before the deepest point in the development. The current 11-year sunspot cycle 23 with its considerably weaker activity seems to be a first indication of the new trend, especially as it was predicted on the basis of solar motion cycles two decades ago. As to temperature, only El Nino periods should interrupt the downward trend, but even El Ninos should become less frequent and strong. The outcome of this further long-range climate forecast solely based on solar activity may be considered to be a touchstone of the IPCC’s hypothesis of man-made global warming.”
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