The WMO data, meanwhile, confirms that atmospheric concentrations of the three gases principally responsible for the man-made component of the greenhouse effect - carbon dioxide, methane, and nitrous oxide - all rose during 2009.

BBC: Modest hopes for climate summit, as gas levels rise

Concentrations of nitrous oxide, estimated to be nearly 300 times more potent than carbon dioxide, rose slightly to a record 324 parts per billion.

BBC: Greenhouse gases hit record high