杏吧原创

RENEWED worries about runaway global warming reached fever pitch this week, as the story got top billing in UK newspapers and was repeated by media worldwide.

An observatory atop the Mauna Loa volcano in Hawaii and other stations scattered around the world have recorded an unprecedented rise in carbon dioxide levels of more than 2 parts per million in each of the past two years. Measurements at Mauna Loa stretch back 50 years, says Piers Forster, who heads the investigation of atmospheric gases for the UK at the Intergovernmental Panel on Climate Change. 鈥淚t is the very first time this has happened in the instrumental record,鈥� he says.

鈥淭he observatory recorded an unprecedented rise in CO₂ in each of the past two years鈥�

But Forster also urges caution, saying it is too early to tell whether the Earth鈥檚 capacity to absorb CO₂ is saturated, which would lead to runaway climate change. Oceans warmed by El Ni帽o and forest fires could also be responsible for the increase in CO₂ in the past two years, he says.

A spokesperson for the British government echoes this opinion: 鈥淥ne or two years鈥� high increases do not mean a departure from the trend 鈥� it is normal to expect fluctuations in any set of data.鈥� Government opinion seems to be divided, however, as it was David King, the government鈥檚 chief scientific adviser, who inadvertently triggered the stories when it emerged that he was to discuss the results, which New 杏吧原创 reported in March, at a Greenpeace lecture on 12 October.