November 8, 2016
Schemes to control global temperatures remain unproven and risky
Although many theoretical studies and small-scale experiments have been carried out, scientists and the wider public are wary of going ahead with GeoEngineering — defined as deliberate large-scale intervention in the Earth’s natural systems to counteract climate change. As investigations by authorities such as the US National Academy of Sciences and Britain’s Royal Society have found, the risk of action in the short term is still too great.
Several futuristic schemes have been proposed that include the building of giant sunshades in Earth orbit. But the two most realistic ideas are to inject aerosols of tiny reflective particles into the upper atmosphere — mimicking the cooling effect of a large volcanic eruption — and to increase reflective cloud cover over the oceans.
The downsides of solar radiation management are the unpredictability and possible side-effects of the proposed techniques, and the fact that they would temporarily mask the problem without tackling its cause.