I thought some of my readers may find the following claim (section 1.2 The Nature of Earth Science of WGI) in the IPCC AR4 humorous:
The attributes of science briefly described here can be used in assessing competing assertions about climate change. Can the statement under consideration, in principle, be proven false? Has it been rigorously tested? Did it appear in the peer-reviewed literature? Did it build on the existing research record where appropriate? If the answer to any of these questions is no, then less credence should be given to the assertion until it is tested and independently verified.
Let’s take them in turn, shall we?
1. Can the statement under consideration, in principle, be proven false?
Perhaps the most frustrating aspect of climate science is the fact that nothing can prove it false. A drought one year is climate change, flash floods the next is climate change. A warm winter with poor skiing conditions is climate change, a record breaking snowfall is climate change. Fog is climate change, lack of fog is climate change. Every dang thing can be used as evidence for climate change, and nothing can ever be used against it.
Also, many claims are based on models predicting the future out for 100 years. It is impossible to falsify these claims, even if the first 20 years are wrong, who’s to say the next 80 won’t be right?
2. Has it been rigorously tested?
How? By seeing how well computer models work against reality? Well, for about a dozen years CO2 has increased, and temperature hasn’t. The models didn’t predict that. The temperature of the earth dropped from the 1940’s to the 1970’s, right when it should have increased (if CO2 was the driver of temperature). Plus, how can you test something which can’t be proven false?
3. Did it appear in the peer-reviewed literature?
This point is being reviewed now. So far, it appears that a significant portion of the claims that the IPCC have made are not based in peer-reviewed literature. I have a list here which barely scratches the surface (And I need to update).
4. Did it build on the existing research record where appropriate?
Not really appropriate, because climate science is an infant scientific field with the majority of research done only in the last two decades.
If the answer to any of these questions is no, then less credence should be given to the assertion until it is tested and independently verified.
This I completely agree with.