THE back-up plan for saving the world is no longer a joke. This week, a major scientific institution has published a comprehensive review of possible ways to engineer the climate to reverse global warming.
The UK 鈥榮 review of geoengineering will make it difficult for governments to ignore the issue. It says that while reducing emissions of greenhouse gases 鈥渁bsolutely鈥� must remain a priority, there is a significant chance that this will not be enough to stave off global warming of 2 掳C. 鈥淢y guess would be that there is a 50-50 chance that we can achieve something with emissions reductions,鈥� says of the University of Southampton in the UK, chair of the Royal Society group behind the report.
If humanity wants to avoid the worst effects of climate change, it must be ready to safely deploy geoengineering methods as and when necessary, the report says. 鈥淲e are already staring 1.6 掳C in the face,鈥� says Shepherd.
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鈥淲e must be ready to safely deploy geoengineering methods as and when necessary鈥�
He believes we should know sometime in the next two decades whether or not efforts to curb emissions will be enough to avoid 2 掳C of warming. If not, his personal view is that we should be prepared for a two-step plan B.
Step one: enact a means of sucking carbon dioxide out of the atmosophere. Several methods are already being investigated, which fall broadly into two categories: 鈥渢ech-heavy鈥� solutions, such as artificial trees that filter air and extract CO2 for storage (快猫短视频, 10 January, p 34), and 鈥渂iological鈥� methods, such as planting trees, reducing biomass to charcoal (biochar) and fertilising the oceans.
According to Shepherd, tech-heavy methods are preferable because they are less likely to interfere with complex ecosystems. 鈥淢ost of the things that have gone wrong in the past have happened when we鈥檝e tampered with biological systems,鈥� he says.
Step two: deploy some sort of sun shield to deflect solar energy away from Earth. Reflective technologies could cool the planet within one year, and according to the Royal Society鈥檚 findings the most promising method in terms of cost and effectiveness would be to pump sulphate particles into the stratosphere (see chart). This should only be a short-term fix, however, as it would not curb ocean acidification and other side effects of greenhouse emissions.
Geoengineering methods have so far been on the fringe of climate discussions and research. Few, if any, could be developed tomorrow or even tested on a large scale. The Royal Society report calls on the UK government to invest 拢10 million a year in geoengineering research. This amounts to roughly 10 per cent of the UK climate research budget, says Shepherd.
Another unresolved issue is for governments to agree on how to regulate geoengineering efforts (快猫短视频, 21 July, p 8). The Royal Society proposes that the UN Commission for Sustainable Development be charged with the task. It also suggests the should establish a geoengineering working group.
This is not inconceivable. There are signs that the field is increasingly being taken seriously at national and international levels. Earlier this month the tweaked the remit of its climate panel such that it will now assess geoengineering proposals. The Intergovernmental Panel on Climate Change will decide next month whether or not to do the same. Military and naval representatives have also started to attend research and policy workshops on the topic.
The Royal Society offered some reassurance regarding concerns that discussions of geoengineering will deflate the public will to cut emissions. Results from focus groups suggested this is not the case (see 鈥淒o mention the 鈥楪鈥� word鈥�). Whether this will also hold true for politicians remains to be seen.