Since 1997, Britain's emissions of warming gases have actually risen – and if you factor in the emissions from goods now manufactured for us in China, they have risen dramatically. Very few politicians have been honest about the crisis we face, or demanded the swift transition to an economy powered by the power of the sun, the wind and the waves. Working on the inside, the Environment Secretary Ed Miliband has a strong claim to this award, often trying to drag other government departments towards radical low- carbon approaches. But he is, in the end, too tainted by ineffective compromises, and by his sometime promotion of false solutions like the myth of "clean coal", to clinch it.
The politician who has most inspiringly proposed solutions to the climate crisis is in another party and another parliament altogether. Caroline Lucas joined the Green Party 20 years ago when it had a shabby office and almost no full-time staff. She has played a key role in leading it now to the brink of a historic breakthrough – her probable election in Brighton Pavilion next month as the first Green to the British Parliament.
In the European Parliament, without playing down the potential catastrophe of global warming for a second, Lucas has always proposed an optimistic and inspiring vision of how dealing with this crisis can also solve our other sicknesses. She has pioneered policies that can make Britain a more equal and fulfilled society, where instead of maniacally consuming ever more meaningless stuff, we find meaning in each other, and in the common cause of saving the biosphere. In a properly democratic electoral system, this vision could spurt ahead: in France, the Green party beat the Socialist party – the equivalent to Labour – at the last European elections.
If nothing else, there should be one great moment in the 2010 election: were you up for Lucas's win?