A sensible, reasonable skeptic (I am going for the American spelling from now on) has emailed me with some points. My responses in italics.
Thank you for a clear and concise summary of your case.
There are, however, several large assumptions that are made in the reasoning process. I would like to point out a few.
1. The assumption that a computer model of the atmosphere is accurate to draw conclusions as far ranging as you draw. Computer models are not science at all, but an pseudo-world created on a computer by a human being.
1 Computer models are theories worked out in software. In view of the dynamic complexity of the atmosphere, they are the only means we have of understanding what is happening. Like all theories, they need to be validated, and they will never be perfect, but I was impressed a few years ago to see how the model moved towards the observed situation when sulphate aerosols were added in to the equations.
2. The failure to note the "tipping points" that may occur in the opposite direction: for example, warming may increase greatly plant growth in polar regions and algae in the oceans, thus leading to absorption of CO2.
2 I sincerely hope that there are negative feedbacks that will offset the positive. C02 fertilisation is another such. They need to be fed into the models. Maybe they are. We all need simple summaries of what climate science is finding.
3. The assumption that we are better off spending huge amounts of money in order to do something when doing nothing may be the best response. The amount of waste that is probable when we go off half cocked trying to fix a "problem" we don't really understand clearly will be more damaging than just adjusting to a little more heat.
3 The projections from the do nothing approach are very worrying. 6*C warming is too depressing to think about. Stern shows that investment in decarbonisation is money well invested. I know that he has been criticised, but all such work is criticised, especially when it demands such radical economic reforms. For me, the clincher on decarbonisation is that it acts to help relieve peak oil peak gas, acid rain and acidification of the oceans.
4. There are many benefits to global warming, too. We will reduce heating bills. We will open up new lands for farming..... How can we know the benefits won't outweigh the harm?
4 re benefits of GW: http://www.newscientist.com/article/dn11655-climate-myths-higher-co2-levels-will-boost-plant-growth-and-food-production.html
Do not assume that you will reduce heating bills. The prediction is not for gentle, balmy conditions everywhere, but for perturbations of weather, with increasing extreme events.
5. How does this computer model explain that the earth has stopped warming for the past several years when greenhouse gases have continued to increase?
If you look at the graph on global temperatures here
you will see that there is a quite regular wobble in the 5 year average line. It is in a falling phase at the moment, thank the gods, but we must expect a rise to follow.
I see very little science in the whole theory and a lot of politics. It also seems there is a lot of money to be obtained by many scientists from climate warming panic. There is so little rigor in the scientific case that is being made, and yet so much is being claimed and the whole world is expected to sacrifice so much, I think not nearly enough supporting study has been done to justify these conclusions. When a politician, Al Gore, puts out a movie that is full of distortions, exaggerations, and untruths, and wins an Oscar, so the media gets on board, and soon 60 per cent of Americans have bought in, this strikes me more as a snow job than the result of sober scientific thinking. If more scientists who believe humans are causing global warming would have pointed out that the movie was hyperbole and inaccurate, they would have kept their credibility. As it is, they lost it with me. The whole so-called "scientific" establishment has lost much of their credibility with me over this. I do appreciate your well-stated case, but I just think it has holes and am not ready to jump to the conclusions you come to.
I agree that economics is a factor in science, and research can continue until the source of funding dries up. I agree that scientist are human, with human emotions and failings. I agree that data massaging, whether unconscious or fraudulent, does take place in all science. However, it is too much to ask us to believe that this entire body of science is fraudulent, and that the whole community is bending its data to please a conspiratorial group of politicians.
Again, thank you for taking the trouble to comment.