A new proposal to stop global warming receives a cool reception.
The idea – the desperate hope, some would say – is to screen our planet from the rays of the sun in order to slow down the pace of global warming. This planetary experiment would involve huge and largely unforeseeable risks, yet for some it is the only way out of the current climate crisis.
The techniques proposed are referred to as “solar geoengineering” or Solar Radiation Management (SRM) and are based on the observation of nature: just as volcanoes are able to cool the planet by rapidly erupting vast quantities of gases and particulates into the atmosphere, a controlled release of appropriate substances could shield us from solar rays.
The Philippine volcano Mount Pinatubo successfully achieved this in 1991, when it spewed 10 million tons of sulphur dioxide into the atmosphere, forming aerosols that lowered global temperatures by nearly a degree for roughly a year. This though requires colossal volcanic events, even more impressive than the pyrotechnics of Iceland‘s Eyjafjallajokull eruption, which led to a temporary reduction in CO2 emissions due to the grounding of flights in Europe, but otherwise had little overall effect on the global climate.
Atmospheric aerosols do not have a long lifespan and after a year or two the volcano effect subsides.