SuperFreakonomics on the shelf and decided to check the table of contents. Lo and behold they had a section on climate change which obviously I decided to read. Their coverage of a bunch of points in the debate was reasonable if slanted to the skeptical side but the really interesting part was the ideas that were talked about to cool the Earth back down.
1. Firehose to Heaven.
The idea here is to use lessons from the Mount Pinatubo explosion to cool the Earth. Most volcanoes have a minimal impact on cooling because the sulphur dioxide they spew out does not go very high in the atmosphere and falls back to the ground fairly quickly. Mount Pinatubo and other massive volcanic events blast the sulphur dioxide much much higher where it is caught by high altitude winds and spread around the globe, lowering temperature. This effect substantially lowered world temperature by 1C or so for the year after Pinatubo blew up. The idea behind the firehose is to have a hose supported by balloons that pumps sulphur dioxide 18 kilometers up into the air and releases it there. The plan they outlined suggested that 2-5 stations could be set up at an estimated cost of $150 million upfront and $100 million yearly that would be able to lower world temperature by several degrees, enough to offset all of the expected warming in the next 100 years.
2. A good use for pollution.
This proposal was basically the same idea as the first but was done to placate people who don't like the idea of pouring things into the atmosphere. It is simply setting up a similar skyhose on the outputs of factories and industries that already produce pollution and release it in the stratosphere instead of normal smokestack height. The cost was at least an order of magnitude larger but avoided putting any extra pollution into the air.
Lastly they talked about setting up a fleet of boats to zoom around the oceans deliberately kicking up spray high into the air. The idea here is that the oceans have much less cloud than the land but that we could drastically increase cloud cover over the oceans with this technique which would cut out sunlight received by the ground and water and lower world temperature. I also saw this technique online when it was talked about by Bjorn Lomborg. This technique was expected to be drastically more expensive than the first one but to be a lot more palatable to the public since kicking up ocean spray is less likely to be seen as negative than pumping sulphur dioxide into the high atmosphere.
I don't claim to have any idea as to how feasible these methods really are but it is encouraging to see that people are coming up with lots of interesting ways that we could reduce the temperature of the Earth if we really needed to. I do find it very interesting that increasing the CO2 in our atmosphere seems like it could be a very good thing if it didn't happen to heat the place up. The estimations I have seen suggest that a doubling of the CO2 concentration in the atmosphere would increase plant growth by 70%, which would certainly be a way to help feed our ever expanding population and shows that fossil fuel consumption does at least have some side benefits for our ecosystem. It isn't by any means a good enough reason to starting burning more but it may end up being a consolation prize if we simply aren't able/willing to get emissions down and CO2 continues to accumulate at ever increasing rates.