China announced plans Thursday to sharply boost its energy efficiency and slow the growth of carbon emissions as part of its contribution to the fight against global warming.

The State Council announcement ahead of next month's Copenhagen climate summit pledges that China will cut carbon dioxide emissions per unit of gross domestic product by 40 to 45 per cent by 2020, compared with levels in 2005.

The State Council, or cabinet, said it "is a voluntary action taken by the Chinese government based on its own national conditions and is a major contribution to the global effort in tackling climate change."

The goal does not mean that China will cut its carbon emissions by 2020. In fact, given the expected huge increases in its economy over the next decade, its global warming emissions should increase — but at a much slower pace than if China had made no changes.

India, the world's fifth-biggest greenhouse gas emitter, has proposed a similar policy to link emissions to growth in gross domestic product, defined as a broad measure of the value of the nation's total output of goods and services.

China announced earlier Thursday that Premier Wen Jiabao will take part in the Copenhagen meeting to show the country's commitment to the global effort to reduce greenhouse emissions.

The announcements come after the White House said U.S. President Barack Obama will attend the start of the conference to personally commit the U.S. to a goal of substantially cutting greenhouse gases.

"We hope to reach a fair and reasonable arrangement" at Copenhagen, Foreign Ministry spokesman Qin Gang told a news conference. "Wen's attendance fully demonstrates the importance attached to this."

The Dec. 7-18 conference is unlikely to produce a binding agreement. The original goal of the conference was to produce a new global climate change treaty to replace the 1997 Kyoto Protocol. But in recent weeks it became clear that delegates were likely to produce at best an outline for an agreement to be considered late next year.

"This is the first time China has a target that directly links up its emissions figure and its economic development … the importance of this figure is really that China wants to show how it's going to try to develop in a more low-carbon way," said Yang Ailun, climate campaign manager for Greenpeace China.

Boost efficiency

Yang said that in order to meet the new target, China will have to boost energy efficiency, use more renewable energy sources like solar and wind power and look for new ways to reduce its heavy dependence on coal.

The White House said Obama will "put on the table" a U.S. commitment to cut emissions by 17 per cent over the next decade, on the way to reducing heat-trapping pollution by 80 per cent by mid-century.

China has said repeatedly it will seek binding pollution targets for developed countries and reject similar requirements for itself at the international meeting.

China has said it was unfair that all countries be required to play a role combating global warming since most of the environmental damage was caused by developed nations during their industrialization over the last 100 to 200 years.

China, the world's largest emitter of greenhouse gases, has already said renewables such as solar and wind power will supply 15 per cent of its energy needs by 2020. But Beijing is resisting binding emission caps.