Green jobs. They sound good, don't they? First off, any job in a recession is welcome. Then you get the satisfaction of, well, let's not be shy about it, getting paid to save the planet. And finally there's the prospect of meeting all sorts of like-minded people and comparing tips on composting. Reality, of course, hits like a blast of biomass.

"We are on the edge of a low-carbon industrial revolution," claimed the Business Secretary Peter Mandelson in March – although he did scale back Gordon Brown's promise of 100,000 recession-busting "Green New Deal" jobs to just "tens of thousands" of new jobs in the approaching low- carbon economy. The definition of a "green job" is equally nebulous. At the executive end of the spectrum, they are jobs in sustainability and corporate responsibility. "Such jobs transcend all sectors of the economy," explains Andy Cartland, founder of leading recruitment agency Acre Resources. But a broader sweep might include cycle ' instructors and furniture restorers alongside hydrologists and climatologists. Indeed, you may already have a green tinge to your collar already without realising it.

As well as jobs in renewable energy, from installers of photovoltaic panels (or maybe you know them as solar panels) and wind turbines to scientists developing biofuel from algae (a technology in which the UK leads the world), there are green jobs in facilities management – has everyone switched off the lights for the night? – and the waste industry. In 20 years, chemical engineers currently employed to get oil out of the ground will be paid by governments to clean up after the oil companies. In the next 50 years, some believe many green jobs will be in climate-change mitigation, such as flood defences and carbon sequestration.

But that's all some way off.