Do we need a 'Gaian dictator' to save the world?
Here is a worrying thought. Or maybe not. One rich philanthropist could take it into his head to re-engineer the planet's climate. It might only cost a few billion dollars, and even in these days of financial meltdown there are people around with that kind of cash.
Dutch Nobel prize-winning chemist Paul Crutzen recently proposed that, if things went really pear-shaped on climate change, we could start spraying the upper atmosphere with sulphate particles. They would intercept enough solar radiation to cool us down again.
It might be a last resort, but it could prevent us crossing some tipping point to irreversible climate mayhem. And it wouldn't cost the Earth.
Last week, Crutzen was among a group of 40 scientists and engineers who attended a workshop at Wildbad-Kreuth in the Bavarian Alps, to discuss whether the world should be reassured or alarmed by the prospect of this or some other act of planetary engineering.
It's not often that Earth-hugging Gaians and grease-stained engineers share a litre or two in the bierkeller. I should declare an interest - I moderated the event.
It was a bit huffy at times. They discussed the ethical issues as much as the technical. Would it work? What would happen if it went wrong? If the sulphate sunshield, as some suggest, destroyed the ozone layer. Should anyone be allowed even to try?
But most seemed to agree that, even if only as a last resort, we need to develop some "ready-to-go" system for cooling us down - whether it was a planetary parasol or a way of soaking up atmospheric CO2 pronto.
But how to control this genie, if it were developed?
Or should we recognise that the genie is long since out of the bottle? After all, our carbon-dioxide emissions are already altering the climate, and nobody asked permission to do that.
Some enthusiasts for geo-engineering - or eco-hacking, as some have taken to calling it - said we might one day have...