My take is at http://heliophage.wordpress.com/2013/03/31/climate-geoengineering-for-natural-disasters/
Extract: One implication is that climate geoengineering deployed in just the northern hemisphere looks like a very bad idea. Programmes in just the north have been considered and studied, in part because of the worries people have about something suddenly going wrong in the Arctic, something that needs “fixing” quickly. This research makes such approaches look dangerous. More interesting, and more novel, is the implication that geoengineering might be used to avert a Sahelian drought caused by a volcano. If the stratospheric sulphates released in a major northern eruption were promptly countered by a deliberate release of sulphates into the southern hemisphere, both hemispheres would cool. The ITCZ would stay put, and a drought might well be averted. For a major drought, that would be a big win. The drought in the 1980s, which followed on the 1982 eruption of El Chichon in Mexico, killed about a quarter of a million people and turned millions more into refugees. ... And if the Earth is left to its own devices, such droughts will happen again. Last century there were two eruptions that cooled the north and were followed by drought in the Sahel. The north is better endowed with volcanoes than the south, since the Pacific “ring of fire” is more a horseshoe of fire, with a gap in the south but a continuous arc in the north. The odds of at least one eruption in the Pinatubo-to-Krakatoa range somewhere of the Earth in this century are better than even. The chances of one happening in the north are obviously lower; but the odds are hardly long. If humans had had the technological wherewithal to stop the 1980s Sahel drought in its tracks, would people have wanted to use it? It seems likely that there would have been a constituency for it, not least in the Sahel. And many of the reasons people have for objecting to geoengineering as an inappropriate “technical fix” to man-made climate change might apply with rather less force if the technology was being used to forestall a natural disaster on a continental scale. -- You received this message because you are subscribed to the Google Groups "geoengineering" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To post to this group, send email to [email protected]. Visit this group at http://groups.google.com/group/geoengineering?hl=en. For more options, visit https://groups.google.com/groups/opt_out.
