China has for the first time announced that it will reduce carbon dioxide emissions. On Thursday, Beijing promised that its carbon dioxide emissions in 2020 will be 40 to 45 percent lower than they were in 2005.

Earlier in the day China announced that Prime Minister Wen Jiabao will attend the Copenhagen climate summit, which will be held from 7 to 18 December.

On Wednesday, the White House said for the first time that President Barack Obama will attend the summit. However he will attend the meeting for one day only, on 9 December. He will stop over in Copenhagen while on his way to the Norwegian capital Oslo, where he will receive the Nobel Peace Prime the next day.

China and the United States are the world's two largest producers of greenhouse gases.

The United States recently announced that it will reduce its CO2 emissions by 17 percent by 2020 in comparison with 2005. However the Kyoto Protocol, which the US refused to sign, calls for a 20 percent reduction in comparison with 1990. Since US emissions have risen by 15 percent since 1990, the new pledge means that Washington's emissions will fall far short of the goals set in Kyoto.

The European Union has promised to cut emissions by 20 percent in comparison with 1990 and is considering raising this figure to 30 percent. However the man charged with coordinating the new United Nations climate treaty, Dutch diplomat Yvo de Boer, is pleased that Washington and Beijing will attend the summit. Before Wednesday it was not known if the leaders of the world's two main polluting countries would attend the UN climate change top.

On Monday, the UN agency on global warming announced that greenhouse gas emissions are rising and have reached record levels.

ökulsárlón Lake in Iceland has doubled in size due to extreme glacial melting
Photo by Wikimedia Commons