What we're doing wrong
The sulphate solution
10th May 2008
Artificially spraying the skies with sulphur to abate climate change would destroy up to 75 per cent of the ozone above the Arctic
Sulphates in the sky spawn acid rain and destroy ozone - but do make for pretty sunsets
With greenhouse-gas emissions rising, and showing no sign of abating, many climate scientists think that it’s time to consider the use of “geo-engineering” – making grand-scale modifications to the planet itself in order to undo some of the damage.
One of the most popular ideas that scientists bandy about is to spray sulphate particles into the atmosphere. Sulphates – spewed by smokestacks and cars as well as natural sources such as volcanoes – reflect sunlight back into space and act as a brake on global warming. So perhaps we can cool the planet by putting more sulphur in the air. Sounds simple. But detractors point out that the sulphur would eventually fall back to the earth as acid rain.
Another criticism is that sulphates would enlarge the two holes in the ozone layer (one above each pole), because they facilitate the breakdown of ozone by chlorine-containing molecules, such as the infamous CFCs.
The ozone layer shields us from cancer-causing ultraviolet radiation. Thanks to the Montreal Protocol on Substances that Deplete the Ozone Layer, an international agreement in 1987 that kicked off the phase-out of CFCs, the holes were expected to have repaired themselves by the middle of this century (though the larger Antarctic hole would take longer because of differences in geography, weather and winds).
But artificially spraying the skies with sulphur would destroy up to 75 per cent of the ozone above the Arctic and delay the recovery of the Antarctic hole by up to 70 years, climatologists estimate in the journal Science.
“We don’t want to create another ozone hole trying to reduce climate change,” says Simone Tilmes at the National Center for Atmospheric Research in Colorado.
Published in The Green Report in The Globe and Mail