In “Why carbon is innocent”, Peter Ravenscroft summarises the case for exculpating carbon dioxide from the base accusations of defamatory misanthracists:
Consensus in the natural sciences is unavoidably a set of fashion statements, but anthropogenic greenhouse warming (AGW), one of the newer sets, is inspired nonsense. Its foundation mythology is based, I contend, on a very poor grasp of basic chemistry, geology, geophysics, oceanography and logic. Few of the current crop of climate scientists have any real familiarity with those vastly complex fields—not their fault, just reality—the field is too big for the human mind. I do not claim to understand climate change either, just to have seen some of the problems and some possible alternatives. [...]
Sure, the climate is changing, it always does, see the geological record. This is the peak of an interglacial, merely one of the most unstable times in geological history, barring incoming large meteorites, gamma ray bursts and magnetic field reversals. The geomagnetic field of this planet has declined by a third in the last 400 years, we have lowered water tables in many regions and we have cut down a large proportion of the Earth’s trees, one of the main continental air-conditioning systems. Why would the climate not change? It is likely that the continental surface and the lower atmosphere are warming and that we are in part responsible. But there is no evidence whatever that anthropogenic greenhouse gases such as carbon dioxide are the cause of that climate change. A vast amount of generally ignored satellite and other hard data now shows, very clearly, that our industrial and other carbon dioxide outputs are of minute importance in that change, if any and also that the far larger natural production of carbon dioxide (CO2) is not occurring anywhere near where the planet is actually warming. Other things, as yet unknown or little understood, are driving the change. So apart from the important gain of getting people to conserve scarce resources, the war on carbon is a total waste of effort.
We do not yet remotely understand what caused the ice ages, the main climatic shifts in the last 2 million years, though geologists and others have been trying to do so seriously for over 200 years. The more strident carbonists are incensed that geologists have the audacity to participate in this debate and to look skeptical about their views, but it is they who are the newcomers here. The climate change debate started as an attempt to explain the ice ages and still requires them to be explained. All carbonists are very welcome of course and maybe they will solve the puzzle, but they do seem a little time-shallow as yet. Until we understand what drives the ice ages, we will not understand climate change.
The main problem for the AGW model is that where real surface warming happening geographically does not remotely match where humans are generating CO2 and other greenhouse gases. Or for that matter, where nature is generating far vaster anomalous amounts of CO2 either. Since trace gases disperse in the atmosphere, an inescapable consequence of the laws of thermodynamics, AGW requires the atmospheric heating it postulates to happen above and just downwind of the sources of the gas. The real pattern is complex and it shifts by the week, but the most intense surface warming on average is in eastern Siberia, in and around the Antarctic Peninsula and in the Congo-Angola region, three places with about the lowest concentrations of both human-generated and naturally- generated CO2 on the planet.