The latest findings of the Intergovernmental Panel on Climate Change conclude that we are quickly using up our carbon “budget” – the amount of carbon that we can afford to emit while still having a good chance of limiting global warming to 2º Celsius. According to the IPCC, keeping the global temperature increase from pre-industrial levels below this threshold – the recognized tipping point beyond which climate change is likely to get seriously out of control – requires that the world emit only about 1,000 gigatonnes of carbon (GtC).