Geoengineering is the deliberate large-scale intervention in the Earth’s natural systems, as opposed to accidentally filling the atmosphere with carbon. Geoengineering is increasingly being explored as a response to climate change, with a range of techniques on offer. Solar projects might chemically increase the reflectiveness of clouds, or build Space mirrors to reflect the Sun’s energy. Or we might remove carbon dioxide from the atmosphere with massive new forests (and they would be really, really massive) or by adding nutrients to the ocean.

There are many worries about the risks involved with specific projects, as well as scepticism of the whole business. Some worry that even research into geoengineering legitimises the idea. We might also question the motivations of it’s supporters; why are they so wary of social change over techno-fix? As Doug Parr argued in 2008, geoengineering’s attempt to fix nature rather than our society amounts to “an expression of political despair.”

Efforts to consider geoengineering’s ethics and politics have been developed through the so-called ‘Oxford Principles’ and, most recently, the Berlin Declaration. But this is still a largely academic and political exercise, with limited public debate, even if the Berlin Declaration seemed to be released via Vice magazine. There’s the compounding worry that public engagement might act as a form of public relations, legitimising geoengineering rather than opening debate. Arguably to have a robust public debate on geoengineering we also need one on climate change, and it’s questionable whether we’re ready.

If you want to read more: The Royal Society’s 2009 report is still a good primer, and look out for one due from the US National Academy of Sciences at the end of the year. For the sceptical argument, see , perhaps balanced with Matt Watson’s blog, the Reluctant Geoengineer.