A controversial plan to inject sulfur dioxide into the atmosphere as a last gasp effort to combat climate change is being explored by the US government.
David Fahey, director of the Chemical Sciences Division of NOAA’s Earth System Research Laboratory and the agency’s top climate change scientist, has received US$4m from the US Congress to study the merits of the idea, which he dubbed a ‘Plan B’ for climate change.
In his study Fahey will explore another emergency solution which would involve spraying an aerosol of sea salt particles into the atmosphere.
Both methods, forms of so-called ‘geoengineering’, aim to combat the effects of global warming by cooling the Earth’s surface by reflecting sunlight back. Both methods are also an attempt to copy processes that go on already.
The sulfur dioxide plan would ape what happens in volcanic eruptions, which have been discovered to cool the Earth by emitting huge clouds of sulfur dioxide.
Proponents of the second method say that spraying sea salt particles would improve the ability of low-lying clouds over water to act as shade. The technique is taken from the phenomenon of ‘ship tracks’, long clouds left by the passage of ocean vessels.
The idea would be that specialized ships could be used to widen the clouds trails by injecting vapor into them from sea water, thereby creating shade.
According to a report in the Scientific American, Fahey told his staff that the funding from Congress did not represent an approval to move forward with geoengineering, which remains controversial, not least because no one knows what the impact would be of injecting chemicals in to the atmosphere on such a large-scale.
“Geoengineering is this tangled ball of issues and science is only one of them,” he reportedly told staff.
The effect of the geoengineering would also take time, with Fahey noting that it might take until the next century to complete the cooling.