Geoengineering: quick climate fix or dangerous meddling?

Large-scale geoengineering could play a key part in tackling global warming but disputes over its viability and potential impact on the environment, and the lack of international regulation, means it is still unclear what role it will play

It appears to be a dream scenario, a quick fix for global warming without all the inconveniences and lifestyle changes that emissions reductions demand. But despite the obvious temptation to try anything to undo the impact of man-made climate change, geoengineering – the deliberate manipulation of the climate by, for instance, extracting carbon dioxide from the atmosphere or reflecting the sun's energy away from the earth – has not yet been embraced.

Indeed, it is often the same groups that advocate most strongly for action on climate change and warn of the devastating consequences of doing nothing that reject geoengineering as an option. They argue that, aside from the prospective for unwanted side effects on weather and biodiversity, a short-term fix gives governments and society a get-out clause from enacting cuts in carbon emissions that are still needed for the long-term sustainability of the climate.

Friends of the Earth has described solar radiation management – firing aerosols into the stratosphere to reflect some of the sun's energy – as "mad, bad and dangerous" because it could disrupt the behaviour of weather systems such as monsoons. And the other main type of geoengineering, taking carbon dioxide out of the atmosphere by, for example, adding fertilizer to selected regions of the ocean to increase phytoplankton growth, brings "big potential risks". It was in response to concerns such as these that the 193-member United Nations Convention on Biodiversity declared in 2010 that there should be no field tests of geoengineering projects that might affect biodiversity.

That ruling was not legally binding, and allowed for small-scale studies that were needed to gather scientific data and had been assessed for their potential impact on the environment. But it has been followed up by a double setback for the geoengineering community in recent months. In the autumn, the European Parliament adopted a resolution stating its opposition to large-scale geoengineering as part of its positioning negotiations ahead of a UN conference on sustainable development in Rio de Janeiro in June this year. At the same time, a British project to test the equipment that might be used to inject particles into the stratosphere to act as a sunshade were postponed for six months to give third parties more time to put forward their concerns.

The experiment, led by the University of Bristol and backed by government-funded research councils, was due to begin in October and would have seen a small amount of water pumped into the sky. But opposition groups said the Stratospheric Particle Injection for Climate Engineering project broke the UN ruling. In a letter to Chris Huhne, then British energy secretary, the prominent Canadian ETC Group, along with a host of others, wrote that the experiment would take place in a controlled setting, as the UN convention demands, "since the hose reaches one kilometre into the sky and is intended as a model for an apparatus that will be 20 times longer". They also noted that the aim was not to produce scientific data but to test equipment.

The ETC Group, which described the planned tests as a "Trojan horse" that would "send the wrong message to the international community", put together a petition with the support of more than 50 other organisations and opposes field experiments at least until international regulations are in place. Agreeing global rules is proving difficult: the first draft of the conclusions for June's UN summit, the starting point for the discussion, makes no mention of geoengineering. It is a problem that Oxford University's geoengineering programme attempted to tackle last year when it proposed a code of conduct for geoengineers to follow in their research and experiments.

Yet although it remains an unknown quantity, geoengineering has its supporters. A survey of the public published in the Environmental Research Letters journal late last year showed that although most people thought global warming is too big a problem to be fixed by a single technology, 72 per cent were in favour of research into solar radiation management, of which the postponed British project is an example. Perhaps more importantly, it was reported last month that a small but influential group of scientists who advocate research into geoengineering receive significant funding from billionaires including Bill Gates and Richard Branson. According to The Guardian, Gates has backed two professors – David Keith at Harvard University and Ken Caldeira at Stanford, the global leaders in the field – with $4.6m, some of which has been put into their own research with the rest going to other projects. Branson has contributed funds to the Royal Society's research into solar radiation management.

Keith has in the past dismissed the idea that geoengineering should be ignored because of the temptation to see it as a cure-all solution that relieves society of the need to cut emissions. He told the BBC: "This moral trade-off is a very puzzling one. If it [geoengineering] works, and we don't know that it does, then it provides some protection in the near-term. And I think it is a very odd moral stance to say we should wish that such protection isn't available – especially we in the rich world, when the consequences will fall mostly on the poor."

The Oxford geoengineering programme reached a similarly balanced conclusion when announcing its code of conduct, stating clearly that geoengineering was not "an excuse" to delay emissions reduction. "It is important that those working in the field of geoengineering are clear that it is no panacea for climate change and express that clearly in their interactions with the media and society," the code says. "Emission reductions are essential – geoengineering research is required because, while essential, reductions alone may not be sufficient to avoid dangerous climate change."

But despite this reasoning, the emergence of a small group of scientists and their wealthy backers that dominate the geoengineering lobby has provoked criticism. Doug Parr, Greenpeace's chief scientist, said in a Guardian interview that scientists "are not the best people to deal with the social, ethical or political issues that geoengineering raises". And the ETC Group's Diana Bronson described as "really worrying" the notion that those working on geoengineering projects should also be involved in discussions about international rules. There seems to be little prospect of this deadlock being broken anytime soon.

The need for international rules is not only based on the possible environmental impact of geoengineering but its potential use in the political context. As the futurist Jaimas Cascio ominously warned in Foreign Policy magazine four years ago: "The offensive use of geoengineering could take a variety of forms. Over productive algae blooms can actually sterilize large stretches of ocean over time, effectively destroying fisheries and local ecosystems. Sulphur dioxide carries health risks when it cycles out of the stratosphere. One proposal would pull cooler water from the deep oceans to the surface in an explicit attempt to shift the trajectories of hurricanes. Some actors might even deploy counter-geoengineering projects to slow or alter the effects of other efforts."

Nevertheless, the most recent research on geoengineering gives a mixed picture with some positivity. A study published in Nature and Climate Change suggests that solar radiation management could improve global food production rather than hinder it, as the traditional thinking goes, because the lower temperatures created by blocking some of the sun's energy combined with the same level of carbon dioxide in the atmosphere might increase crop yields. A major study of using this technology on a global scale authorised by the American aerospace company Aurora Flight Services, concluded that it was feasible and could lower temperatures by between one and two degrees. However, the report did not consider the implication on weather systems of injecting 1-5 million tonnes of sulphur dioxide into the stratosphere each year.

Although humans have already, unintentionally, geoengineered the climate as a result of the impact of, for example, draining rivers and massive deforestation, the science still sounds futuristic. For instance, Mongolia plans to store giant blocks of ice during winter to then use in the summer months to cool and provide water for drinking and irrigation to the capital city, Ulan Bator. Other proposals are much simpler, such as spraying water onto the polar cap to thicken Arctic sea ice. But the moral and ethical questions posed by the technology still dominate the debate, and until those questions are solved, there is unlikely to be a consensus on what role it can play.