China, the world's largest greenhouse gas emitter, told the United States and other industrialized nations yesterday that they alone bear responsibility for ratcheting down more carbon before 2020.

In a submission to the U.N. Framework Convention on Climate Change, China dismissed the idea that it or other nations considered to be still developing under the laws of the climate regime must consider the question of how to cut further emissions beyond the pledges they made two years ago.

"Developed country Parties should take the lead in reducing their emissions by undertaking ambitious mitigation commitments and fulfill their obligations by providing financial resources and transferring technology to developing country Parties," China's diplomats wrote.

The submissions are called for under the Durban Platform, an agreement that all nations including the United States and China helped negotiate and sign at the most recent U.N. climate conference in Durban, South Africa. It calls for countries to recommend ways to "close the ambition gap" -- a reference to the space between emission pledges nations offered up and the amount required to keep the world below a 2-degree-Celsius rise in global temperatures.

While the Durban Platform does not spell out demands for industrialized and developing countries, it urges countries to look at ways of "ensuring the highest possible mitigation efforts by all Parties."

China, however, wrote that "the key to increase the level of ambition to reduce emissions lies with the developed country Parties' political will, and the recognition of historical responsibility." Diplomats urged industrialized nations to curb carbon emissions between 25 and 40 percent below 1990 levels by 2020. Meanwhile, they said developing countries have already set and achieved mitigation targets despite unmet promises from wealthy countries to finance clean technology development.

At the 2009 climate summit in Copenhagen, Denmark, the United States pledged to cut carbon emissions about 17 percent below 2005 levels by 2020. Other countries complain that target is too low and isn't likely to be met. China has pledged to cut emissions intensity -- that is, the level of emissions per unit of gross domestic product -- between 40 and 45 percent from 2005 levels. Analysts likewise believe that target is too low, but the country is on track to meet it.

China's submission echoes that of India, which last week also told the U.N. climate regime it expects industrialized countries to take the lead in emissions cuts (Climatewire, March 8).