James Lovelock has started proposing some of the wacky geo-engineering ideas to prevent warming. He was an early proponent of nuclear power, and many followed and I'm sure over the next few years many will also follow this trend.

Clearly these are a distraction from the real task - reducing emissions, and some are so large scale and risky as to likely be worse than the problem they are trying to cure.

However, while these ideas are eccentric, some are even mad, they will unfortunately become necessary. If we we pass the tipping point around 2015 without sufficient emissions reductions, we will have to start adding one or more of these mad schemes to our, rather too gradual, emissions reductions. This is another reason why I believe that we WILL pass the tipping point. Those at the top of the economic pyramid will benefit not only from an extended period of business as usual, but also from the eventual need for these, hugely expensive, schemes.