A fair bit of the doubt and confusion surrounding next month’s UN climate summit has suddenly cleared, with the world’s two biggest greenhouse gas emitters – the US and China – announcing pledges on curbing greenhouse gas emissions. As is set out in the Bali Action Plan – the agreement made at the UN summit two years ago – the US pledge takes the form of an actual cut in emissions. China – whose per-capita emissions are far lower – vows to reduce carbon intensity, the amount of CO2 emitted per unit of GDP, by 40-45% from 2005 levels by 2020.