The survey (PE July 2012) on climate change is worrying. That members of the public should see geo-engineering as a conceit and unlikely to form a defence against climate change would have been no surprise. That engineers should think so suggests that they are not paying attention.
All the indicators, air and sea temperature, CO2 concentration, shrinkage of the Arctic sea ice, show that the problem has got worse and that so far the world is not capable of reducing greenhouse gas emissions. Global emissions of CO2 have risen or remained essentially constant every year since Kyoto, including the current recession in the West.
Global warming was always a question of timescale. If we could wait 40 or 50 years to reduce emissions to negligible levels then the present world policy of emissions reduction and its desperately slow implementation would be sufficient. Unfortunately such a timescale would see the accepted target of a 2ºC global mean temperature rise breached and would provide no defence against positive feedbacks in the climate system. Thus some limited form of geo-engineering will, I believe, be essential; perhaps as early as this decade.
Colin Baglin, Malaga, Spain