Geoengineering Unable to Fully Stop 21st Century Sea Level Rise: Report
Simulating a colossal volcanic eruption every 18 months would just delay sea level rise. Space Shuttle (Mission STS 43) photograph of the Earth over South America taken on August 8, 1991, showing double layer of Pinatubo aerosol cloud (dark streaks) above high cumulonimbus top. Photo via: Wikipedia.
Another nail in the coffin of the geoengineering as silver bullet to stop climate change notion: New research published in the Proceedings of the National Academy of Sciences finds that all but a sustained, aggressive, risky, and logistically daunting geoengineering effort will fail to stop projected global sea level rise over the coming century. Furthermore, even this is no substitute for actually reducing emissions. The researchers, from institutions in England, China, and Denmark, found that sea level rise of 30-70 centimeters by 2100 could not be prevented by geoengineering in their simulations.
Aggressive Geoengineering Would Delay Rising Seas by Half a Century
Even simulating a volcanic eruption the size of Mt Pinatubo every 18 months--injecting particles of sulphur dioxide into the atmosphere--would only delay sea level rise by 40-80 years. If that was kept up over decades, sea level rise could be held to 1990 levels.
Previous research into the side effects of such a geoengineering scheme has shown that not only would it be costly and difficult to coordinate internationally, but it would be fraught with possible negative side effects. Study co-author Dr Svetlana Jevrejeva concurs, noting, "We simply do not know how the Earth system would deal with such large-scale geoengineering action."
Scientific American sums up the only geoengineering solution that might work:
Perhaps the only way to reduce warming enough to minimize the rise of the oceans is an all-out effort that also includes burning biomass as fuel (either to replace coal or gasoline or both) and pairing it with CO2 capture and storage. Together, they could suck down greenhouse gas levels by 180 ppm--more than enough to bring us below pre-industrial levels. As a result, sea level rise is held to just 10 centimeters by 2100, according to the author's modeling.
The burning biomass to replace coal, gasoline, or both has serious land-use problems, when done on a scale to actually replace the same amount of energy currently obtained from those fossil fuel sources. And, despite continued touting by the Obama administration, carbon capture and storage is a long way off from being expanded to the scale needed to capture a significant portion of human-caused greenhouse gas emissions at current levels of energy use--not to mention having financial problems as well, absent a mechanism to keep carbon prices sufficiently high.
Reducing Emissions Only Way to Not Burden Future Generations
Which essentially leaves us with what so often it seems we want to avoid: Changing our behavior itself to reduce greenhouse gas emissions. Dr Jevrejeva again, "Substituting geoengineering for greenhouse emission control would be to burden future generations with enormous risk."
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More on Geoengineering:
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