Related editorial: Time to end the climate of confusion
HAVE scientists muddied the waters over what needs to be done to stave off dangerous climate change? Have they caused confusion instead of telling politicians how to save the world? That鈥檚 what many are asking in the wake of a major meeting intended to inform politicians before vitally important negotiations later this year.
This December, the Bella Centre in Copenhagen, Denmark, will play host to thousands of politicians, policy-makers and their entourage as they try to agree on emissions targets. In an attempt to make their mission clearer, last week to deliver the latest findings on how human emissions of greenhouse gases are affecting the environment and how that is likely to evolve over the coming century.
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However, some delegates worry the meeting has only created more confusion, leaving policy-makers even less clear about where to set their emissions targets. In 600 talks over three days, researchers presented a complex update on their individual work, the majority of which showed the impacts of climate change would happen faster and be worse than previously thought. The sessions appeared to satisfy the needs of scientists but not the policy-makers present.
This was most obvious in the last session, when Anders Fogh Rasmussen, Denmark鈥檚 prime minister, struggled to get a firm answer on what emissions targets governments should adopt. He wanted to know whether politicians should still be aiming to limit warming to no more than 2 掳C.
This widely accepted target is loosely based on the forecasts of the , but some scientists in Copenhagen suggested 2 掳C may not be enough to avert some of the worst impacts of climate change, such as the disintegration of the Arctic ice cap, while others argued the world will get warmer no matter what. 鈥淚 need some concrete advice now,鈥� appealed Rasmussen. 鈥淪hould we be setting the bar higher? I need to know and I need to know today. The scientific world has to make an agreement with itself 鈥� what is the real platform for politicians?鈥�
鈥淭he scientific world has to make an agreement with itself 鈥� what is the real platform for politicians?鈥�
John Ashton, who is the UK government鈥檚 special representative on climate change, says it鈥檚 鈥渨rong and dangerous鈥� for scientists to confuse politicians over the 2 掳C target, and this 鈥渨ill make it harder to get the intensity and urgency of effort required鈥�.
The problem, says Martin Parry of the Grantham Research Institute on Climate Change and the Environment in London, is that such a large and short meeting was never going to deliver a consensus on climate change. 鈥淚f you had put another group of scientists on the panel of the plenary sessions, you would have had a different picture,鈥� says Parry.
The closest the meeting came to direct advice for politicians was when the organisers published at the end of the meeting. These messages included a statement that the worst-case scenario IPCC projections are being realised, and an appeal for action. But some conference delegates took issue with the political tone. The messages 鈥渃arry the authority of the people who drafted them, and no more鈥�, says of the University of East Anglia, UK. 鈥淣ot the authority of the 2500 expert researchers gathered at the conference, and certainly not the authority of collective global science.鈥�
Parry argues that politicians need to ignore the indecision that came out of the meeting and stick to their targets. 鈥淪tudies continue and there isn鈥檛 time to take a careful evaluation of all these, let alone get government agreement so science is working back-to-back with policy,鈥� says Parry.
Neither Hulme nor Parry doubt that the effects of climate change are being felt more and faster than was forecast by the IPCC, and that limiting global warming is becoming increasingly difficult. 鈥淭he numbers themselves are not really the message at this stage. There were some mixed messages about these, but what is important is that the Copenhagen climate summit concluded that the IPCC conclusions hold and if anything the challenge is stronger.鈥�
Related editorial: Time to end the climate of confusion
Seed clouds to cool the climate
If governments fail to reach a deal on reducing emissions, the option remains to artificially cool the climate. Immediately after the conference in Copenhagen, a small group of climate scientists flew to Edinburgh, UK, where they spent the day discussing the possibility of field testing a proposal to increase the reflectivity of clouds.
The flat sheets of stratocumulus cloud that spread out over the ocean naturally reflect a portion of solar energy out to space. They could be made more reflective by spraying tiny particles of seawater into them, encouraging the formation of smaller water droplets. Clouds that are 鈥渄oped鈥� in this way should in theory act as sunshades.
Phil Rasch of the Pacific Northwest National Laboratory presented a modelling study that showed seeding about a quarter of the area above the oceans could conceivably reduce temperatures by enough to counter a doubling of carbon dioxide in the atmosphere.
The group then discussed two methods for atomising seawater in the volumes that would be needed and outlined a potential field trial. US federal funding for geoengineering field tests could be available within five years, the scientists believe, but in the meantime they may need to turn to philanthropic funds in order to get the ball rolling.
None of the attendees advocated artificially cooling the planet instead of reducing greenhouse gas emissions, preferring to see it as a last-resort safety net. 鈥淕eoengineering is not a pleasant thought,鈥� said one delegate. 鈥淚 have yet to meet a geoengineer who wants in their heart of hearts to intentionally modify the climate.鈥�
On 18 March, an advisory group to the US Defense Advanced Research Projects Agency was due to meet to discuss geoengineering and although some of those present in Edinburgh were attending, most disapproved of using military funding to develop geoengineering. Some emphatically said they would refuse such money.
