NEW YORK — Bold new initiatives against global warming have come out of major cities around in the world over the past few weeks — with the notable exception of Washington.

Meeting in New York this month, dozens of big-city mayors from six continents competed to present the most ambitious plan for reducing emissions of carbon dioxide and other gases that cause global warming.

New York Mayor Michael Bloomberg touted his new 127-point plan to cut Gotham’s emissions 30 percent by 2030. Los Angeles Mayor Antonio Villaraigosa committed to reducing his city’s carbon emissions 35 percent by 2030. Toronto’s David Miller announced that he had signed his city up for Zerofootprint, a carbon calculator and social networking Web site that helps individuals reduce their greenhouse gas production, to help Canada’s largest city meet its goal of reducing greenhouse gas emissions by 6 percent in five years and 80 percent by mid-century.

In Washington meanwhile, legislation that would set similar goals for the United States is inching through Congress as the White House resists calls for greenhouse gas reduction targets.

Spurred by a recent Supreme Court ruling, President Bush did sign an executive order May 14 asking federal agencies to develop regulations to “cut gasoline consumption and greenhouse gas emissions from motor vehicles” by the end of next year.

But on Tuesday, Attorney General Jerry Brown of California urged the U.S. Environmental Protection Agency to grant a waiver that would allow his state and at least 11 others to act sooner. The states want to enact rules requiring automakers to cut emissions from cars and light trucks by 25 percent, and from sport utility vehicles by 18 percent, starting with the 2009 model year.

“This is more important than any issue that EPA’s going to have to face,” Brown said.

California Gov. Arnold Schwarzenegger has said he will sue the agency if it fails to act by Oct. 25.

Internationally the White House is trying to avoid action against global warming. At preliminary negotiations in Bonn this month, administration officials reportedly said they would refuse to discuss a follow-on agreement to the Kyoto Protocol when the treaty’s signatories meet in Bali later this year. The protocol, which expires in 2012, sets carbon reduction goals for industrialized nations. It was signed by the Clinton administration but never submitted to Congress for ratification.

U.S. officials are also resisting German Prime Minister Angela Merkel’s wish to include carbon reductions on the agenda of next month’s G-8 summit. As the meeting’s host, Merkel had hoped to broker a commitment by G-8 members to cut carbon emissions in half by 2050. Japanese Prime Minister Shinzo Abe said last week he would push the proposal during the summit. But such a measure is seen as increasingly unlikely to succeed, mostly thanks to U.S. opposition.

A U.N. scientific panel reported earlier this month that such cuts could be achieved with relatively little impact on the global economy. The world’s nations could avoid catastrophic global warming by dedicating about 3 percent of their economies to the problem between now and 2030, the Intergovernmental Panel on Climate Change concluded.

That level of investment could halt the rise in atmospheric carbon dioxide at less than double pre-industrial levels and limit global average temperature increases to no more than a few degrees Fahrenheit, the panel said, but only if it started well within the next decade.

James Connaughton, chairman of the White House Council on Environmental Quality, complained that such a timetable would result in worldwide economic recession.

“If we continue to do what we are doing now, we are in deep trouble,” said Ogunlade Davidson, a co-chairman of the U.N. panel.