Chris Rowan recently discussed using geoengineering to mitigate climate change on a global scale. This sort of geoengineering gives me the willies; it’s likely to be subject to the law of unintended consequences on a global scale.
Why? Just look at our track record on other environmental fixeds. Use more biofuels, and watch forests get eaten up in an effort to cash in and plant more biofuel crops. Switch to nuclear energy, and then you have a spent rod disposal problem. Encourage more electric (read: battery-powered) cars, and you have a heavy metal mining/disposal problem.
Some of the geoengineering options suggested (blow particles into the atmosphere to create a global umbrella!) to fix global warming just sound like bad ideas. Some (re-injecting carbon into the ground, bio-engineering algae to take up excess atmospheric carbon) sound fairly reasonable. But far more safe and cost-effective would be to try and limit the damage we’re inflicting.
I know how politically thorny it is, but if you think the arguments between developing and post-industrial countries are bad now, wait until the US or Europe decides to “cool things down” and goes a little too far and we have massive crop die-off and famine.