Not too late to stop dangerous climate change

Mike Childs

30 May 2011

The report in today's Guardian newspaper that global carbon emissions reached record levels last year hardly made for a cheerful bank holiday. I heard the news from my boss Andy Atkins who called me as I was trying to keep track of my two small children at a playground in York. Does this news mean we should now give up on avoiding dangerous climate change, as implied in the article by the Chief Economist of the International Energy Agency? I don't think it does.

Last December Friends of the Earth published a report into how much carbon emissions can be released between now and 2050 to have a low probabillity (30 per cent) of a global temperature increase of two degrees (the level many politicians have defined as dangerous). By sharing out the emissions equally between nations based upon their populations we found that to reach this goal developed countries would need to cut emissions by around 8-15 per cent per year starting immediately, China would need to peak its emissions in the next couple of years and many developing countries would also need to peak their emissions within the next ten years.

The eye-watering cuts suggested by this research could be taken to reinforce the notion that we have lost the war to prevent dangerous climate change. But there are two reasons why this isn't the case.

Firstly, we do yet know enough about how sensitive the planet is to greenhouse gases. This means that we work on probabilities of a certain amount of carbon emissions leading to dangerous climate change. A 30 per cent probability of  two degrees equates to a carbon budget (or amount of emissions) of around 1100 GtCO2e but a 60 per cent probability gives a carbon budget almost half as big again (1600 GtCO2e). This latter carbon budget would substantially reduce the rate of emissions cuts required. Basically this suggests that if we are really lucky and the planet isn't too sensitive to carbon emissions we might just be able to reduce carbon emissions fast enough to avoid two degrees; but only if we really put our mind to it.

Secondly, as our report noted, cutting carbon emissions is not the only way to keep temperatures down. Geo-engineering is getting a lot more attention nowadays. It involves either taking carbon out of the atmosphere or reflecting more sunlight back out into space. The former is seen to be less risky (although not risk free) compared to the latter which is highly risky.

If the planet is very sensitive to greenhouse gas emissions then it is highly likely that geo-engineering would need to be deployed if the goal to prevent dangerous climate change is to be achieved. If it less sensitive and enough political will exists then we may avoid the need to deploy geo-engineering. Either way it is too early to give up on trying to prevent dangerous climate change.