If an industrial revolution to produce energy with much lower carbon emissions gathers momentum in Copenhagen in December, there will be fortunes to be made. There are also likely to be some great business empires destroyed.

The scale of the task is vast. Limiting carbon dioxide emissions to the levels scientists suggest would keep global warming to no more than about 2°C would mean building nuclear power stations, wind farms and solar panels at rates never seen before. But it is – just about – achievable. As Cecilia Tam of the International Energy Agency, the rich countries' watchdog, puts it: “It is challenging, but feasible.”

The technology is not an obstacle. All the necessary processes are either already in use or, with luck, capable of being deployed within a decade or so.