Yesterday I went to listen to Sir Nicholas Stern at the Examination Schools. Of the many topics he could have been asked to discuss, climate change was the one he finally settled on. He made a very succinct presentation of his findings in the Report, and with the benefit of four months outside scrutiny, also made a considered defence against the criticisms he has faced since last November. (Herein we get all technical) He talked about the probability distributions the team used is assessing how certain levels of carbon in the atmosphere translate to temperature changes.

At 450 ppm CO2e, just above te current level, there is a 50% chance of temperatures increasing by more than 1.5°C, while at 550 ppm CO2e, there is a 50% chance of temperatures increasing by more than 3°C. Both predictions had a 95% confidence band of about 5°C. The distributions they used are by no means the most conservative, but are similarly not the most outlandish. Also, his assumptions close, and possibly slightly more conservative than the most recent IPCC report predictions. (That wasn't too bad, was it?)

Basically, I was impressed and left feeling the doubters are the ones that need to prove themselves now.

Plus, he discussed the reasons people may not want to act: 1. don't believe the science; 2. believe we will be able to adapt when it happens; 3. don't care about the future. These, he said, were 1. absurd 2. reckless and 3. unethical. Plus, he did manage to get one little dig in: he said there are many top scientists who aren't convinced climate change is a man-made phenomena. Nigel Lawson, for example.