BRUSSELS (AP) - President Barack Obama's new climate change program may be derided by some activists as too modest, but it could still turn into a significant leap if it results in a worldwide agreement that includes China.
The initiative may be a crucial move in pressuring Beijing to accept binding goals to cut greenhouse gases, while also allowing the U.S. to start catching up with the European Union in the fight against climate change.
"This is the kind of leadership that's highly needed," said Martin Kaiser, head of international climate politics at Greenpeace. The proposal should have been twice as ambitious, he added, but "it demonstrates that the Obama administration wants to seriously tackle climate change."
The plan would reduce carbon dioxide emissions from U.S. power plants, many of which are coal-fired, by 30 percent from 2005 levels by 2030.
Governments want an agreement by late next year in Paris to curb emissions of greenhouse gasses blamed for global warming. Unlike the 1997 Kyoto Protocol, which exempted developing nations from emissions limits, this deal is supposed to cover every country.
The U.S. never ratified the Kyoto protocol, handing China and others an easy excuse to dodge tougher action as well.
"The new initiative is a first firm commitment that puts the U.S. in a serious negotiating position for the upcoming climate talks in Paris," said Georg Zachmann, an expert with the Brussels-based think tank Bruegel.
"It gives hope that further steps in that direction will be forthcoming," he added.
China, the world's biggest polluter ahead of the U.S., has promised to curb its output but has so far resisted binding limits.
"Obama's plan to cut greenhouse gas may have some impact on China's decision-making," said Wang Ke, a professor at the School of Environment and Natural Resources at People's University in Beijing. "But China's goal will be based on its domestic needs in the transformation of its economy and handling smog."
United Nations climate chief Christiana Figueres insisted she fully expected "action by the United States to spur others in taking concrete action."
Commenting on reports that China may be considering pollution limits, European Union climate chief Connie Hedegaard said on Tuesday that if true they "could be a game changer."
Greenpeace's Kaiser also voiced optimism, saying that witnessing high pollution their own cities had convinced Chinese leaders that only joint action could tackle the problem.
Like many developing countries, China's status has changed drastically since the 1997 agreement. It has grown into an export powerhouse and the world's second-largest economy, prompting American lawmakers to say any new treaty must cover China. Beijing says it is still too poor to take on the limits imposed on rich countries.
China accounted for 29 percent of global emissions in 2012, more than the United States and the 28-nation European Union combined, according to the Netherlands Environmental Assessment Agency.
Europe welcomed Obama's plan, if more for the political dynamic than for its ambition.
Obama has pledged a reduction of 17 percent of the entire economy's emissions by 2020 compared with the level in 2005. That translates into a reduction of about 4 percent compared with 1990 levels.
EU officials in Brussels estimate Obama's new plan will only reduce U.S. emissions sufficiently to meet the overall target of a 17 percent reduction by 2020. Without the new plan, the reduction would come in at only about 12 percent.
The EU, in turn, has already reduced its emissions by 19 percent compared with 1990 and aims to achieve a reduction of about 25 percent by 2020, and 40 percent by 2030.
Its successful emissions reduction, however, got a boost from the collapse of Communism in Eastern Europe in 1990, which led to the closure of many polluting plants. Activists complain the EU has lost steam in its fight against climate change in the past years since the global financial crisis hit the continent 2008.
Still, one of the EU's most prominent tools in the fight against climate change is a comprehensive emissions trading system, under which companies pay per ton of carbon dioxide they release into the atmosphere, with the pollution certificates traded on the market.
In the U.S., Obama's efforts to pass a cap-and-trade bill failed on Capitol Hill due to bipartisan opposition.
Bruegel's Zachmann also warned that Obama's new initiative relies on executive action and bypasses Congress, which could make it far easier for his successor to change the rules again.
"If everything can be reversed following a change of leadership, that's bad because it might not create the necessary legal certainty for businesses to invest in low-carbon technology," he said.
Scientists, however, maintain that far larger cuts will be required to avoid drastic environmental change.
Emissions must drop by 40-70 percent by 2050 to keep the global temperature rise below the 2-degree C (3.6-degree F) cap set in U.N. climate talks, according to a report in April by the Intergovernmental Panel on Climate Change. Scientists consider it a key threshold above which the impact of global warming on humans would increase significantly, for example through extreme weather conditions.
Instead, emissions are rising. The IPCC said that global emissions increased by 2.2 percent a year between 2000 and 2010, outpacing growth in previous decades to reach "unprecedented levels," underlining the urgency to reach a global climate deal next year in Paris.
McDonald reported from Beijing. AP researcher Yu Bing in Beijing, AP Writer Katy Daigle in New Delhi and Frank Jordans in Berlin contributed.