Thursday, September 21, 2006

Sunlight Reflection Scheme Inevitable

Last Thursday on National Public Radio’s All Things Considered they interviewed a scientist who had just published a paper that described a scheme for temporarily halting global warming by injecting material into the atmosphere similarly to what occurs during some large volcanic eruptions. When Mount Pinatubo erupted in 1991 so much ash was thrown into the atmosphere that there was slight global cooling for a few years due to reflection of sunlight which counteracted the ongoing global warming. The idea is not to solve the global warming problem but to buy us time until we can adequately reduce emissions of greenhouse gases.

It is difficult to argue with the notion that we need to buy time. After all, climate experts say that to have atmospheric carbon dioxide level off at a concentration where the further increase in global temperature would only be about 1°F or 0.5°C the amount of carbon dioxide emissions worldwide would have to be reduced by about 70% from 1990 levels. Even that would cause considerable climate change. Moreover, NASA scientist James Hansen has said that to prevent additional increases in global temperature beyond 1°F we must begin to take major action within the next 10 years. Even the most optimistic among us would we hard pressed to be positive about success in these circumstances. The pessimism must be growing because during the interview it was revealed that some climate scientists now believe it is inevitable that some type of scheme to increase the reflection of sunlight worldwide will eventually be attempted. Proposed schemes to reflect sunlight globally, which seemed so farfetched only a short time ago, now appear to be gaining traction in the scientific community as the coming reality.

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