Widespread scepticism greeted Goldman Sachs' announcement of a new environmental policy late last year. The US investment bank is known for its aggression rather than its concern for the planet, yet the policy had the personal backing of Hank Paulson, chief executive. It will lead to a big expansion of its activities in such areas as emissions trading.

A Goldman spokesman said: "We are certainly a financially focused organisation but we are also one that has built a business by being, among other things, intensely rational. Recognising that the planet is under threat is about as rational as one can be."