Geoengineering the climate – Science governance and uncertainty

Geoengineering the climate – Science, governance and uncertainty

Shepherd, JG. Geoengineering the climate: science, governance and uncertainty. Royal Society, 2009.

The continuing rise in the atmospheric concentration of greenhouse gases, mainly caused by the burning of fossil fuels, is driving changes in the Earth’s climate. The long-term consequences will be exceedingly threatening, especially if nations continue ‘business as usual’ in the coming decades. Most nations now recognise the need to shift to a low-carbon economy, and nothing should divert us from the main priority of reducing global greenhouse gas emissions. But if such reductions achieve too little, too late, there will surely be pressure to consider a ‘plan B’—to seek ways to counteract the climatic effects of greenhouse gas emissions by ‘geoengineering’

Many proposals for geoengineering have already been made—but the subject is bedevilled by much doubt and confusion. Some schemes are manifestly far-fetched; others are more credible, and are being investigated by reputable scientists; some are being promoted over-optimistically. In this report, the Royal Society aims to provide an authoritative and balanced assessment of the main geoengineering options. Far more detailed study would be needed before any method could even be seriously considered for deployment on the requisite international scale. Moreover, it is already clear than none offers a ‘silver bullet’, and that some options are far more problematic than others.

This report is therefore offered as a clarifi cation of the scientifi c and technical aspects of geoengineering, and as a contribution to debates on climate policy. The Society is grateful to all the members of the Working Group, and especially to John Shepherd, its chairman. We also acknowledge the valuable inputs from the Council’s review group, and the expert support, throughout the exercise, of the Society’s Science Policy team.