The target was praised by some environmental advocates in China, but falls short of a goal that some negotiators in the United States and Europe are pushing for: China, they say, should reduce its greenhouse gas emissions relative to economic development by at least 50 percent.

China’s announcement came a day after the White House announced a provisional target for reductions in overall greenhouse gas emissions in the United States. President Obama discuss climate change with China's President Ju Jintao, the Chinese president, when the two met in Beijing on Nov. 16. Officials from the two countries were in talks on the issue while former president George W. Bush was in office, but President Obama earlier this year made climate change a top priority in diplomacy between the two governments.

The back-to-back announcements by the United States and China amounted to politically safe opening bids in what is likely to be a long, tough process of negotiations on concrete steps the two countries should take to address climate change. With its enormous population and breathtaking pace of economic development, China surpassed the United States two years ago as the largest emitter of greenhouse gases. However, it resisted earlier demands from American and European negotiators to adopt binding limits on greenhouse gas emissions, arguing that environmental concerns must be balanced with economic growth and that developed countries must first demonstrate a significant commitment to reducing emissions.

China’s arguments resonate with other developing countries like India, and both countries propose slowing the growth of emissions relative to the growth of their economies.