Engineering the climate: is science fiction becoming reality?

The recent UN climate conference in Doha has demonstrated again that the UN climate negotiations are proving too slow in reducing global greenhouse gas emissions. The latest climate science released by the Global Carbon Project for the Doha conference indicates the planet is currently on track for a rise in temperature of between 4 and 6 degrees later this century. Unless urgent action is taken to reduce global emissions our children and grandchildren will not thank us for the volatile and dangerous climate we deliver to them.

The lack of progress in reducing global greenhouse gas emissions is making some scientists argue that humanity needs to prepare an emergency strategy to cool the planet. This emergency strategy, so the argument goes, could be rolled out when serious climate change impacts start to bite in coming decades. One emergency strategy that is currently attracting attention is geoengineering. Geoengineering is the use of human technology to manipulate and control the climate on a large scale. It may sound like cheap science fiction, however, various methods of geoengineering are currently being researched in the UK, US and Canada. In 2009 Britain's leading scientific body, The Royal Society, produced a major report, Geoengineering the climate: science, governance and uncertainty, on the prospects of geoengineering as a response to climate change. Geoengineering has moved out of the fringe of climate policy discussion into the mainstream.

'Stratospheric particle injection' is a geoengineering technique that aims to mimic the cooling effect of volcanic eruptions by injecting sulphate particles high into the stratosphere. There, the particles act like a giant sunshade, reflecting a percentage of sunlight away from the earth. This method of geoengineering is being investigated by a collaboration of scientists in the UK known as the SPICE project. It has been proposed to test technology to deliver particles into the atmosphere using a hot air balloon with a hose attached. While the technology may sound simple, the chemistry of the atmosphere is very complex. The particles would likely change the physical appearance of the sky by making it whiter during the day and more colourful at sunset. The particles may also cause damage the ozone layer, a layer of the atmosphere that filters ultraviolet radiation from reaching the earth. The particles could also significantly change global rainfall patterns that are relied upon by billions of people. Stratospheric particle injection may cool the planet in the short term, but it is little more than a bandaid measure. It does nothing to address the key driver of climate change, which is the rising level of greenhouse gas in the atmosphere.

Ocean fertilisation is a geoengineering technique that aims to remove greenhouse gases from the atmosphere. In the same way we add fertiliser to our gardens to make them grow, ocean fertilisation adds nutrients to the ocean to encourage the growth of plankton. Plankton consumes carbon dioxide, and could draw down enough greenhouse gases from the atmosphere to lessen climate change. In October this year a US businessman dumped an estimated 100 tons of iron sulphate off the coast of Canada in an attempt at ocean fertilisation. The experiment did not have the authorisation from the Canadian Government and potentially breached international bans in the London Convention on Ocean Dumping. Ocean fertilisation could cause damage to ocean ecosystems, increase ocean acidification and deplete the ocean of oxygen. As with stratospheric particle injection, the probability and nature of the risks of ocean fertilisation are uncertain and require further scientific investigation.

Technical ability to attempt geoengineering is already here. In the coming years, it will be difficult for countries to resist experiments in geoengineering as it has the allure of being a relatively inexpensive and quick response to climate change impacts. It is therefore essential that geoengineering technology is developed and used responsibly and that it is effectively regulated at an international level. If countries deploy geoengineering hastily, without understanding the risks involved, they will be rolling a dice on causing further damage to the atmosphere and the environment. International regulation is also important to ensure that the interests of all countries are considered. It would be unfair for one country to deploy geoengineering technology for its own benefit but in doing so cause significant harm to others. Finally, geoengineering must not allow countries to take their eye off reducing greenhouse gas emissions. A rapid reduction in greenhouse gas emissions over coming decades is crucial for us to provide our children and grandchildren with a safe climate in which to live well.