Guest Post at Climate Science
October 9th, 2008Posted by: Roger Pielke, Jr.
I have a guest post on the logic of IPCC statements on attribution up over at my father’s blog. Please feel free to read it over there and comment here.
Posted by: Roger Pielke, Jr.
I have a guest post on the logic of IPCC statements on attribution up over at my father’s blog. Please feel free to read it over there and comment here.
October 9th, 2008 at 1:48 pm
Nice post. My reading is similar to yours.
October 9th, 2008 at 8:39 pm
Hi Roger,
I agree with your posting at Climate Science. But I have some additional comments.
My first comment is that I also agree with what (I think) Gavin Schmidt is saying about the IPCC’s sentence. Here’s what the IPCC wrote:
“Attribution studies show that it is very likely that these natural forcing factors alone cannot account for the observed warming.”
I ***think*** that Gavin Schmidt is saying that the IPCC SHOULD have written:
“We are highly confident that attribution studies show natural factors alone cannot account for the observed warming.”
From page 22 of the Technical Summary, “highly confident” means that they are greater than 90 percent confident.
So the reworded statement is a statement about confidence in the attribution studies.
In fact, the statement that the IPCC made doesn’t even make sense, given *their own* definition of “very likely.” As they point out, the “very likely” deals with probability of ***future*** events or outcomes (see page 23 of of the Technical Summary). It doesn’t make sense to attribute probability to past events.
October 19th, 2008 at 11:12 pm
An article published in Science Express makes the case that a species of fruit fly (Drosophila subobscura) has adapted to warming on three continents in a relatively short period of time. Joan Balanya from the University of Barcelona and three colleagues tracked genetic changes in this species of fruit fly in Europe, North America, and South America. They compared chromosome arrangements in 26 fly populations from previous studies completed 13 to 46 years ago to recent samples and identified genetic changes, called “chromosome inversion frequencies.” They correlated these changes with mean monthly weather data taken four years prior to the original study to a current four-year period that coincides with more contemporary samples
The problem with this kind of research is the risk of false correlation. Over the last 20-40 years, many places on Earth have been warming. But obviously warming is not responsible for the increase in every observable phenomenon on the planet (although, more and more, it seems people are acting that way). The correlation between the first principal component of chromosome arrangement frequencies in 26 fruit fly communities on three continents with the first principal component of average monthly temperature does not prove cause-and-effect.
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jennifertom
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