Andrew D Atkin:
I have already written on this issue, but I think I can make a clear and simple 'master picture' which I would like to contribute.
As follows:
Nobody is arguing that an increase in CO2 will lead to some increase in average global temperatures, in itself. But it is only a very mild greenhouse gas. If we doubled the CO2 concentration in our atmosphere (from where it is now) we would get around a 0.5 to 1 degree Celsius increase in average global temperatures, which is benign and probably even eco-beneficial.
[Our world would support more plant growth overall if it were a little warmer than today, and CO2 is plant food. CO2 is literally (and vitally) an atmospheric fertiliser].
So where is the argument? How the apocalypse? The argument from the IPCC (Inter-Governmental panel on Climate Change) is based on the idea that the marginal increase in warming coming from an increase in CO2 will be amplified by positive-feedback; that is, a slight increase in warming will heavily snowball via reactive processes in the atmosphere, so that we end up with a temperature increase not just about a half a degree greater (from the CO2) but eventually more like 3 or 5 degrees greater (or more?).
If I may speak frankly...Bollocks! If it were true that the earth responds to marginal increases in temperature with a positive-feedback loop (or "snowball" for common language), then we would have already turned into a Venus countless times over from temperature variations that have always (and continuously) happened throughout our ecological history (variations in the suns output being maybe the most significant).
Small, common changes in temperature do not lead to major changes in climate. The medieval warm-period did not turn into a runaway greenhouse effect.
So where did the IPCC get its evidence from? How did it reach its 'weird' conclusions? It did so from computer models. They developed computer programmes that (they claimed) simulated the environment.
Straight off the mark we should be laughing. Because to even suggest you can *accurately* simulate the climate for over a long period of time is a nonsense. This is like claiming divine knowledge - that we don't have. To model the environment so as to simulate it you have to understand it explicitly and be able to measure it - with all the many, many variables accurately accounted for.
First, we just can't do that (yet). We can barely measure known climatic variables, let alone (fully) understand how they all work against each other (which is no doubt why there is still so much debate, research and theory within climate science today). And even if we could measure and account for all the climatic variables (so as to develop accurate long-range cybernetic simulators) we would still require enormous long-term testing so as to develop a simulator that has a reasonable accuracy.
To believe that the IPCC has a "from the God's" cybernetic crystal-ball is one hell of a stretch.
Addition: 30-7-11: Here is an article that appears to vindicate my assertions. You will notice they're talking real world data - not computer models. The former answers to the latter, not the other way around. Models are the guess - real world measurements are the fact.
Conclusion
My conclusion is that we cannot take the computer models seriously. And also, the simple fact that trivial temperature variations (that happen all the time) do not lead to runaway-greenhouse effects suggests the obvious: that the IPCC is a political organisation established to achieve a political end. And an end that has nothing (nor ever did have anything) to do with saving the world from global warming.
Here is a relevant article by Lord Christopher Monckton, probably much more relevant than what I have just written:
And finally, people like Richard Lindzen (people who study direct measurements of climate - not people who pretend to believe in garbage-in/garbage-out computer simulators) have (supposedly) discovered that the climate is in fact a negative-feedback system (like a natural governor that tends to keep things constant). The latter is far more believable to me, because it would explain the relative stability of our climate in response to normal temperature variations.
...Monckton did another good talk, relating to my central points (posted 11-05-14):
...Monckton did another good talk, relating to my central points (posted 11-05-14):
