pIn December, representatives from almost 200 countries will gather in Paris to nail down a deal on climate change. With less than six months to go, momentum is building, with environmentalists and politicians all keen to avoid a repeat of the Copenhagen climate talks, which collapsed in 2009. Recent developments at the G7 summit were encouraging, as major industrialised countries agreed on the need to limit global warming to no more than 2° C above pre-industrial levels.