Thursday, March 28, 2013

Deconstructing ‘Geoengineering’

by Rob Bellamy

Lenton and Vaughan 2009

Figure 1: Geoengineering proposals (Lenton & Vaughan, 2009)


Climate ‘geoengineering’ or ‘climate engineering’ comprises a host of different large-scale technology proposals designed to intervene in the Earth’s climate system and moderate human induced climate change. They have been broadly divided amongst Negative Emissions Technologies (NETs) which seek to remove and store carbon dioxide from the atmosphere, and Solar Radiation Management (SRM) methods which seek to reflect a proportion of sunlight away from the Earth. A diversity of technology proposals exists within each of these categories (see Figure 1).

Whilst NETs share a common goal to remove and store carbon dioxide from the atmosphere, and SRM proposals share a common goal to reflect a proportion of sunlight away from the Earth, that is where the similarities stop. The differences between the methods by which the different proposals seek to achieve those goals are stark. Within NETs, for example, you might contrast dumping iron sulphate into the oceans with applying biochar to soils or mechanically scrubbing the air. Similarly, within SRM proposals you might contrast launching sulphate particles into the stratosphere with painting urban areas white or genetically engineering reflective agricultural crops. Each and every proposal presents a unique set of technical and social issues, with some more or less challenging than others.

Despite the obvious diversity of proposals, ‘geoengineering’ is fast becoming synonymous with one particular SRM proposal: sulphate particle injection, a controversial idea to launch reflective sulphate particles into the stratosphere and cool the Earth. This synonymising is leading to increasingly sweeping rhetoric against ‘geoengineering’ that risks the unfair dismissal of other proposals bracketed under the term. There are now calls for the term ‘geoengineering’ to be abandoned, demanding that debate move beyond talk of accepting or rejecting ‘geoengineering’. We need to start talking specifics; we need to consider these technology proposals on a case by case basis, much as is being pursued by the Virgin Earth Challenge.

Rob Bellamy is a Doctoral Researcher in the Tyndall Centre for Climate Change Research based at the University of East Anglia. His research explores the appraisal of climate geoengineering proposals.



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