In fact, it seems as if it isn’t really much of a debate anymore.
First, let me be clear, the debate among scientists isn’t whether CO2 is a greenhouse gas or whether, even, it can cause warming, but instead on what real (if any) total effect it has overall on the climate. In other words, is there a saturation point where additional CO2 has little marginal effect, or does it build to a tipping point where the change is radical? Robust climate or delicate climate?
Evidence is building toward the robust climate theory, which would mean that while there may be more CO2 being emitted, it has little to no effect on the overall climate. That, of course, is contrary to the AGW crowd’s theory.
So, on to the latest high profile defections:
One of the fathers of Germany’s modern green movement, Professor Dr. Fritz Vahrenholt, a social democrat and green activist, decided to author a climate science skeptical book together with geologist/paleontologist Dr. Sebastian Lüning. Vahrenholt’s skepticism started when he was asked to review an IPCC report on renewable energy. He found hundreds of errors. When he pointed them out, IPCC officials simply brushed them aside. Stunned, he asked himself, “Is this the way they approached the climate assessment reports?”
Vahrenholt decided to do some digging. His colleague Dr. Lüning also gave him a copy of Andrew Montford’s The Hockey Stick Illusion. He was horrified by the sloppiness and deception he found. Persuaded by Hoffmann & Campe, he and Lüning decided to write the book. Die kalte Sonne cites 800 sources and has over 80 charts and figures. It examines and summarizes the latest science.
Vahrenholt concluded, through his research, that the science of the IPCC (if you can call it that) was mostly political and had been “hyped.”
Germany’s flagship weekly news magazine Der Spiegel today also featured a 4-page exclusive interview with Vahrenholt, where he repeated that the IPCC has ignored a large part of climate science and that IPCC scientists exaggerated the impact of CO2 on climate. Vahrenholt said that by extending the known natural cycles of the past into the future, and taking CO2′s real impact into effect, we should expect a few tenths of a degree of cooling.
That, as I said, points to the “robust” climate model.
Once more to make the point before I leave the subject:
Skeptic readers should not think that the book will fortify their existing skepticism of CO2 causing warming. The authors agree it does. but have major qualms about the assumed positive CO2-related feed-backs and believe the sun plays a far greater role in the whole scheme of things.
As Dr. Roy Spencer says, CO2 is a greenhouse gas. Adding CO2 should cause warming. The argument is “how much” and that’s based on competing theories about the climate’s sensitivity. Skeptics think the sensitivity is very low while alarmists think it is very high. The building evidence is that rising CO2 has little warming effect in real terms regardless of the amount of the gas emitted. That there is a “saturation level”. If that’s true, and indications are it is, then there’s a) no justification for limiting emissions and b) certainly no justification to tax them.
That, of course, is where politics enter the picture. Governments like the idea of literally creating a tax out of thin air, especially given the current financial condition of most states. Consequently, governments are more likely to fund science that supports their desired conclusion – and it seems that in this case there were plenty who were willing to comply (especially, as Patrick J. Michael has noted, when that gravy train amounts to $103 billion in grants).
What Vahrenholt is objecting too is the IPCC’s key definition in which it clearly states that “climate change” is a result of and because of “human contributions”. As noted above, he thinks that the sun is a much greater factor (something mostly ignored in the models) and he finds past CO2 trends to forecast nothing like the IPCC’s forecast.
What we’re finding as this argument goes forward is that Patrick Michaels was right – “AGW theory functions best in a data free environment”.