I am a bit bored with wingnuts attempting to discredit Al Gore.

They tried to "bag" him for his role in getting the internet going. Well, bad luck, in the 1980s, the internet was just a few computers wired up in the Pentagon for research. As a senator, Al Gore sponsored the very first bill to turn it into a much wider “information superhighway.” Vincent Cerf, who is widely regarded as the technological founder of the internet, has publicly said that it is thanks to Gore that the internet is used by all of us today. So when Gore said in a 1997 interview that he “took the initiative” in making the internet possible, it was true. The other Gore “lies” have equally impressive truths behind them.

Recently a friend tried to tell me that "An Inconvenient Truth" was as much as sham as Ian Plimer farrago "Heaven and Earth". "An Inconvenient Truth" was the subject of a high profile court case in Britain and denialists - who, in what I can only regard as Orwellian political correctness - should now be called dissentients, have tried to make out that Justice Burton discredited the movie.

Far from the truth (what a surprise!)

In fact he praised the movie but he did find some things to complain about that the dissentients have called errors.

Again, not true. Burton did not find that there were 9 scientific errors in AIT, but that there were nine points that might be errors or where differing views should be presented for balance. He said that this was on the basis that they were not in accordance with the views of the IPCC. Well a few people on RealClimate.org and other places have looked at his reasoning.

So now let's look at the nine points and see if Burton classified them correctly.

1. Greenland Ice Sheet: The IPCC report does say that the ice sheets will melt if warming is sustained over millennia, it may melt quicker but there is "no quantitative information is available from the current generation of ice sheet models as to the likelihood or timing of such an event." Burton is marginally wrong. The IPCC does not preclude that contingency.

3. The Gulf Stream. The IPCC says that by "very unlikely", they mean a 5-10% chance of it happening. It would have been better if he had said that it was a possible rather probable result of continued warming.

4. Al Gore shows two graphs relating to a period of 650,000 years, one showing rise in CO2 and one showing rise in temperature, and asserts (by ridiculing the opposite view) that they show an exact fit. Although there is general scientific agreement that there is a connection, the two graphs do not establish what Mr Gore asserts. Burton is wrong here. Gore does not assert that there is an exact fit, but rather that: "The relationship is very complicated. But there is one relationship that is more powerful than all the others and it is this. When there is more carbon dioxide, the temperature gets warmer, because it traps more heat from the sun inside" And that is the consensus.

5. The snow on Mt Kilimanjaro. It cannot be established that the recession of snows on Mt Kilimanjaro is mainly attributable to human-induced climate change. In fact the Kilimanjaro glacier may or may not be disappearing due to global warming, but it is making other tropical glaciers disappear. He could have picked a better example but it doesn't affect his argument.

6. The drying up of Lake Chad. It is apparently considered to be far more likely to result from other factors, such as population increase and over-grazing, and regional climate variability. However the United Nations Environment Programme says that about half of the lake's decrease is attributable to human water use such as inefficient damming and irrigation methods. The other half of the shrinkage is due to shifting climate patterns. Anada Tiega of the Lake Chad Basin Commission blames climate change for 50 to 75 percent of the water's disappearance. So some of it is due to human use, but it is wrong to say that global warming has been ruled out as a cause.

7. Katrina. Gore does not ascribe Katrina to global warming. He follows the scientific consensus in saying that warming will make hurricanes get stronger. Katrina is used as an example of the damage that stronger hurricanes could do and of the consequences of ignoring warnings from scientists. Burton is wrong again

8. Polar Bears. Burton is badly wrong here. c.f. http://www.timesonline.co.uk/tol/news/uk/article767459.ece The bears drowned in the 2006 storm because they had to swim further because of global warming.

9. Coral Reefs. Burton is, again, badly wrong. The IPCC report says that late 20th century effects of rising temperature include loss of sea ice, thawing of permafrost and associated coastal retreat, and more frequent coral bleaching and mortality.

Overall, there are a couple of points where Gore should have talked about timescales and probabilities and a couple of examples that could have been better chosen but aside from that Burton was mistaken on the other points where he felt that Gore went past the consensus.