A new geoengineering scheme to stop global warming was recently proposed by David Keith, a professor of applied physics at Harvard University and a leading expert on energy technology. His plan is quite far from implementation because of the much needed additional research, however the idea sounds too brilliant not to be reported.
So it is simple. Fine droplets of sulfuric acid should be carefully dispersed in the lower stratosphere by customized Gulfstream business jets. At 20 kilometers altitude, sulfur would combine with water vapor and form sulfate aerosols, which would then be distributed all over the globe by natural winds. These aerosols would reflect 1% of the sunlight hitting Earth back into space, increasing the reflective power of our planet and potentially reducing the warming effects of the greenhouse gases.
Of course, all consequences should be weighed and assessed before such activity takes place. There is a danger of disrupting precipitation patterns, causing depletion of the ozone layer, but Keith has done enough analysis and calculations to suspect that the method is quite feasible.
He estimated that if the operation starts in 2020, the required sulfuric acid to counteract the warming effect of the greenhouse gases would be 25,000 metric tons. By 2040, this value would rise to 250,000, while in 2070 it might well reach more than a million tons per year.
He also calculated that a few grams of sulfuric acid in the stratosphere could offset warming caused by a ton of carbon dioxide. Considering that most of the pollutants remain in the lower atmosphere, the acid molecules are washed in a few days. But in the stratosphere, these same molecules could remain for years, making them very effective at reflecting sunlight.
Previous studies, dating back to the mid-1970s, have already proposed such a measure to combat global warming. The idea has been reported as solar radiation management, or SRM, and numerous studies have tried to simulate its possible effects. Keith, however, is one of the most active supporters.
He states that the key to combating global warming is understanding that the accumulation of atmospheric carbon dioxide is irreversible, because climate change is related to the total cumulative emissions.
Keith is determined to prove that SRM is the way forward, planning a series of experiments that aim to test how sulfuric acid should be distributed and to measure the influence of the acid on the ozone layer. The uncertainties, however, are quite large and the consequences could be big and irreversible.
There are many critics of the idea, who have expressed strong opinions against SRM and geoengineering in general. In addition, the experiments are likely to raise various social and political issues. However, there are still many climate scientists, who would present different interpretations about this research and the risks.
Keith is certain that for such measure to be implemented successfully there is a strong need of international governance, and of course wider knowledge. The Harvard professor is keen to attract more scientists to his team, who will sign an agreement for deploying solar engineering, and free up research.
Many believe Keith’s approach is very radical and almost impossible to be implemented, as he suggests, in 2020. Such major decisions should be carefully considered, because they could create a different world.
Despite everything, Keith is surely right about one thing. Climate researchers and political scientists should definitely explore every possibility, because the effect of global warming is becoming more and more apparent.