Today's CO2 will still be heating the world 100 years from now

On a cold January Saturday in London, 140-odd people turned out tonight for a public meeting. The subject: climate change, and specifically Friends of the Earth's The Big Ask. What struck me was the number of people who said, during the question time and afterwards: "I've going just got involved in this." "I just realised this is really important."

There were people fitting the usual stereotypes of environmental campaigners in the audience, but there were plenty who didn't, among whom I'd include myself. It was only on January 1 that I joined the Green Party, and I'll be heading out tomorrow for my third Sunday of canvassing for it for local government elections coming up in May.

What FoE is asking for is legislation committing the British government to step-by-step, year-by-year reductions in carbon emissions, up to the target of a 60 per cent reduction by 2050. This move apparently has the backing of a majority of MPs, but that in no way, of course, guarantees that it will become law. It has to be their priority, and almost certainly, the government has to be forced to support it.

And at present, the UK is heading in the wrong direction, with emissions rising, and this matters because while the long-term target is needed - and has been calculated on a worldwide basis that should produce only a two-degree rise in worldwide temperatures. This will be hugely damaging but hopefully not totally destructive. However, that is a calculation based on a gradual fall in emissions. A sudden fall in the last decade will result in an overshoot, because - I was told tonight - every molecule of carbon dioxide emitted today will go on heating the world for a century.

Two MPs were present last night - both from the Labour Left and central London, Frank Dobson and Emily Thornberry. Both did the usual political things, shying away from criticising the government and mouthing slogans, although the latter's "the biggest challenge for our generation is to ensure that is not our generation that kills the planet" certainly got to the heart of the manner.

Frank Dobson sounded as though he thought the government's energy review was definitely going to come down on the side of nuclear power, and he set out some nice details about the industry propaganda - the "proven technology" the AP1000 reactor did not in fact exist - the proven claim applied only to various bits of which, some being in civilian use, some military. Much was also being made of "passive safety" features - basically it would be supposed to shut itself down if things went horribly wrong - but every system had that, including Chernobyl. Nuclear power was neither a quick, nor a cheap solution, he said, although he wouldn't altogether rule out the possibility that it might become necessary.

The Green Party is running its own campaign in relations to the energy review. Unfortunately I couldn't make it earlier this week, but there was also a launch of its campaign for practical steps to green energy. I'm particularly taken with microgeneration schemes - particularly wind and solar. I look around the estate on which I live - flat-roofed buildings, some of them very tall, and wonder how much of its own energy it could actually generate, with a bit of imagination and effort.