“One “geoengineering” proposal for reducing the impact of urban heat islands is to paint roofs worldwide a reflective white. Jacobson’s computer modeling concluded that white roofs did indeed cool urban surfaces. However, they caused a net global warming, largely because they reduced cloudiness slightly by increasing the stability of the air, thereby reducing the vertical transport of moisture and energy to clouds. In Jacobson’s modeling, the reduction in cloudiness allowed more sunlight to reach the surface.

The increased sunlight reflected back into the atmosphere by white roofs in turn increased absorption of light by dark pollutants such as black carbon, which further increased heating of the atmosphere.

Jacobson’s study did not examine one potential benefit of white roofs – a reduced demand for electricity to run air conditioning in hot weather. But a recent study done at the National Center for Atmospheric Research showed that the decrease in air conditioning use, which occurs mostly in the summer, might be more than offset by increases in heating during winter months.

“There does not seem to be a benefit from investing in white roofs,” said Jacobson. “The most important thing is to reduce emissions of the pollutants that contribute to global warming.””

http://www.physorg.com/news/2011-10-urban-island-effect-small-global.html

Must read article on urban heat islands. Jacobson and his group do some excellent work. They’re the ones who did the 100% renewables in 20 years study and the recent work on the contribution of black carbon/soot to Arctic melting.

The grandiose schemes look ridiculously expensive and/or look like they’d have serious side-effects we don’t want.

Bottom line: nothing looks like it beats prevention.

But if we’re going to be so dim, I hope someone with sense could think up some solutions that are not more harmful than helpful.

Yes, the ocean is the big topic hardly anyone is talking about.

I somewhat think it a bad idea to pursue as it might give some the feeling that we can fix the climate problem when it gets bad, thus allowing us to continue doing little or nothing to prevent catastrophic climate change.

On the other hand I fear that we will do too little, too late. If we don’t start designing life boats now we might not have any available if we really need them.

Perhaps research into geoengineering with tell those not amply concerned about climate change that 1) there is no way to turn off the bad stuff if we trigger it, or 2) the cost of the best geoengineering solution will be extremely expensive. Either of those outcomes might swing a few more people to the side of taking preventative measures now.

I’d like to hear more arguments for and against. And I’d like to hear about any possible solutions which are affordable and largely non-destructive.