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Wed Nov 21, 2012, 12:53 AM

Wigley and Santer Find the IPCC is too Conservative on AGW

Wigley and Santer Find the IPCC is too Conservative on AGW
Tom Wigley and Ben Santer have published a new paper in Climate Dynamics entitled A probabilistic quantification of the anthropogenic component of twentieth century global warming (hereinafter WS12). The paper seeks to clarify this statement about human-caused global warming in the 2007 IPCC report:

"Most of the observed increase in global average temperatures since the mid-20th century is very likely due to the observed increase in anthropogenic greenhouse gas concentrations"


As WS12 notes, this statement has been criticized by various individuals, including Pat Michaels in testimony to US Congress and Judith Curry. Some of these criticisms stem from a failure to understand that the term "very likely" has a specific numerical definition, meaning greater than 90% probability. Some stem from the fact that the other terms used in the IPCC attribution statement like "most" and "mid-20th century" are somewhat vague.

...

"Here, the probability that the model-estimated GHG component of warming is greater than the entire observed trend (i.e., not just greater than most of the observed warming) is about 93%. Using IPCC terminology, therefore, it is very likely that GHG-induced warming is greater than the observed warming. Our conclusion is considerably stronger than the original IPCC statement."

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Reply Wigley and Santer Find the IPCC is too Conservative on AGW (Original post)
joshcryer Nov 2012 OP
AverageJoe90 Nov 2012 #1
CRH Nov 2012 #2
AverageJoe90 Nov 2012 #3
joshcryer Nov 2012 #4
CRH Nov 2012 #5
joshcryer Nov 2012 #6
CRH Nov 2012 #7
joshcryer Nov 2012 #8

Response to joshcryer (Original post)

Wed Nov 21, 2012, 06:13 AM

1. Decent article.

I've always liked the stuff that the guys at Skeptical Science have put out & featured over the years. They know their stuff.

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Response to AverageJoe90 (Reply #1)

Wed Nov 21, 2012, 09:32 AM

2. Yeah great site, ...

they continue to produce a lot of average joes who underestimate the science.

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Response to CRH (Reply #2)

Wed Nov 21, 2012, 04:01 PM

3. Nope. =)

They do a pretty darn good job. They don't overestimate the science as a few certain people like Guy McPherson have done. They stick to the facts.

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Response to AverageJoe90 (Reply #3)

Wed Nov 21, 2012, 04:20 PM

4. They featured "Hotter Climate Models Likely Right" in their weekly update.

They refrain from alarmism in their rhetoric, but they post the alarming data on a frequent basis.

They featured "alarmist" stuff such as coffee plant extinction, Hurricane Sandy's ties to global warming, they regularly feature The Climate Show which does not paint a rosy picture and often points out how we're doing shit all about climate change.

So I wouldn't find that characterization accurate in the least.

edit: as an example:

Catastrophe if We Don't Change Course

In short, while FS12 does not provide a specific measurement of climate sensitivity, it does suggest that the climate models with lower sensitivity (and 'low' here refers to approximately 2 to 3C surface warming in response to doubled CO2, not the ridiculously low estimates of 1C or less proposed by contrarians like Lindzen) are not accurately representing changes in cloud cover, and are therefore biased. Climate models with higher sensitivity - in the 3 to 4.4C ECS range for doubled CO2 - more accurately simulate the observational RH data and thus the response of subtropical clouds to climate change.

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Response to AverageJoe90 (Reply #3)

Wed Nov 21, 2012, 04:20 PM

5. Couldn't resist joe, to wish a good morning, ...

we would miss you not immediately contesting the dissolution of civilization or even possible extinction. If you didn't, I'd begin to worry for your health.

Most scientists don't have a problem with the facts, its making an unfettered assessment that allows realistic interpretation. Look at what has happened since 2000. Aren't most past assumptions of the facts now being proven to be underestimation? If you always look for the weakest predictions and print this as mainstream cool aid, who does that serve if it latter turns out to influence policy or the lack thereof?

Later

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Response to CRH (Reply #5)

Wed Nov 21, 2012, 04:23 PM

6. What Joe doesn't get is that we "alarmists" are just interpreting the data.

We're interpreting the data in a way that science can't or refuse to do. Either they will lose their grants for making apocalyptic predictions, or they will be "discredited" because they make predictions that people aren't happy to listen to.

Almost every record is underestimating, with the exception of the temperature record which hasn't exactly been too far off, but closer to what was predicted by faulty models without an understanding of cloud feedbacks, arctic sea ice feedbacks, and the like. Given that most of the rest of the predictions were off, it seems reasonable that the temperature forecast, when all is said and done, will be off as well.

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Response to joshcryer (Reply #6)

Wed Nov 21, 2012, 04:35 PM

7. Little off topic, ...

but what you said a couple of weeks ago keeps rattling my brain into agreement.

You said the powers that be have given up trying to reduce emissions to the extent needed, and instead have placed their faith in geo engineering as their realistic hope of mitigation.

Since I begun to try and better inform myself about techno tinkering, and the more I read, the more I fear rolling the dice with mostly unproven science. Desperation does not seem an intelligent motivation.

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Response to CRH (Reply #7)

Wed Nov 21, 2012, 04:38 PM

8. "Desperation does not seem an intelligent motivation."

Indeed.

I completely agree. Mitigation / emission reduction is the only sane way to do this.

But I see no evidence it will be done.

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