Sudden global warming 55 million years ago provides evidence for high climate sensitivity to atmospheric CO2, but the source of the carbon remains enigmatic.

Against a backdrop of rising global surface temperature, the stability of the Indian monsoon rainfall over the past century has been a puzzle.

• Tonnes of deadly toxic waste, which killed 10 people and made thousands ill in Ivory Coast were recently shipped out of the country in sealed containers, bound for a treatment plant in France.

The Pacific Gas and Electric Co (pg&e), California's biggest natural gas company, has announced plans to buy natural gas generated from cow manure in the state dairy farms to fuel its power plants.

British billionaire Richard Branson has committed to spend all profits from his airline and rail businesses, an estimated us $3 billion over the next 10 years, on combating global warming. The