Suppose all political efforts fail. Suppose the United Nations Climate Change Conference in Copenhagen, Denmark won’t lead to significant commitments. Suppose the burning of fossil fuels continues because of the world’s growing middle class while widespread renewable energy sources cannot be made available in time. Suppose the rate of increasing temperatures seriously threatens our ecosystems as species cannot adapt so quickly. Suppose there’s the danger that our food chains would be severely disrupted.

Will we eventually reach a point when geoengineering becomes the only option that is left? If humanity has to resort to such drastic measures which geoengineering method is the most promising?

1) Ocean iron fertilization (producing more algae)
2) Stratospheric sulfur aerosols (simulating a volcanic eruption)
3) Cloud seeding and reflectivity enhancement (using fine sea water spray)
4) Pale-colored roofing and paving materials
5) Dumping small white ping-pong balls into the ocean (increasing Earth’s albedo)
6) Space sunshade (obstructing solar radiation with space-based mirrors or other structures)
7) Oceanic upwelling (placing huge vertical pipes in the sea to pump water from the depths to the surface and from the surface to the depths)

http://en.wikipedia.org/wiki/Geoengineering

http://www.grist.org/article/2009-09-03-geoengineering-shouldnt-be-dismissed-out-of-hand-scientists-say/

Can we foresee the side effects? Would you consider this to be the most dangerous experiment ever?