The unexploded bomb dug up three metres from my kitchen door a few years ago was an uncomfortable reminder of how much explosive was dropped on London during two world wars.

This came to mind when I was reading about the huge, bomb-proof bunker from which Winston Churchill ran the Second World War effort. The Cabinet War Rooms (CWR) survived because they were too big to blow up, so today they are a tourist attraction.

But while visitors trooped underground to visit them over summer, I was meeting Jigar Shah, who runs a very different CWR—the Carbon War Room, founded by Sir Richard Branson. The Virgin founder is clear about the scale of the climate challenge: "We are potentially facing World War Three."

If the Carbon War Room succeeds, it will have a lot to do with its chief executive. Shah, a renewable energy pioneer, launched SunEdison in 2003, based on a business plan he developed for a university class.

Shah and Sir Richard stress that our business-as-usual, carbon-intensive economic system poses the greatest threat to security and prosperity. "We need new thinking, new leadership, and innovation," the pair say, "to create a post-carbon economy."

The Carbon War Room has identified 25 "battles", or sectors, that are central to winning the war against climate change. Each battle accounts for more than one billion tonnes (or more than two per cent) of global CO2-equivalent emissions annually. Its agents of change are entrepreneurs of all kinds, including business leaders, corporate intrapreneurs, and non-profit social entrepreneurs.

Critically, Sir Richard believes, "solutions to global warming will create more wealth than any other business in the next decade". Two early targets are shipping and the built environment. But why not leave it to the politicians?

"Copenhagen showed us that this challenge is one that cannot and should not be left to governments alone," says Sir Richard. "Politicians, are only there for four years. The Carbon War Room, hopefully, will be around for the next 50 years."

Let's hope it will also be a museum then-mission accomplished.

John Elkington is executive chairman of Volans (www.volans.com) and non-executive director at SustainAbility (www.sustainability.com)