The 18 scientists hope to open up the bitterly polarised debate on global warming : while advocates of the Kyoto Protocol say climate stabilisation is vital and within reach of today 's technology, critics argue that it is unnecessary and exorbitantly expensive.

"We stake out a third position," says atmospheric scientist Ken Caldeira of the US government's Lawrence Livermore National Laboratory in California. "Climate stabilisation is important, but we can 't really do it with current technology, even if we wanted to."

The world 's energy needs are rising far faster that we can bring emission-free generation such as nuclear and wind power on stream. Global power consumption for electricity, transport, heat and industry is now about 12 trillion watts, 85 per cent of which comes from fossil fuels.