…from NewScientist…

“The problem with all of these schemes is that we have little clue whether they would work. Some of the best evidence so far comes from the cataclysmic eruption of Mount Pinatubo in 1991, which obligingly conducted a large-scale experiment for us on the effect of injecting sulphur into the upper atmosphere. From a global cooling perspective, the results were encouraging: temperatures sank temporarily by up to 0.5 °C. It remains unclear, however, whether the effects of sulphur on global weather patterns can be predicted or controlled. The dangers include triggering severe regional droughts, and even destroying the ozone layer.

“Faced with such dangers, it would be foolhardy to do anything yet. What we need is a concerted global research drive into the potential and pitfalls of geoengineering. It will take decades to establish which of the possibilities are feasible, effective and safe, what their costs would be, and for whom. Such a programme – encompassing modelling and small-scale experiments, as well as research into the international legal implications of such schemes – need not be expensive, says Steve Rayner of the University of Oxford. It would be small change compared with, say, what is needed to develop alternative energy technologies.”

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