New York: Leading cities and regions on Thursday promised ambitious cuts to emissions blamed for climate change, hoping to boost efforts for a global deal.
The commitment was the latest in a series of pledges during a week of climate events in New York aimed at building momentum for a year-end conference in Paris that seeks to draft a landmark UN agreement.
California, which is by far the most populous US state, has promised sweeping action despite political deadlock in the US Congress.
The state has spearheaded the initiative among sub-national governments to commit to keeping temperature rises to no more than two degrees Celsius (3.6 Fahrenheit) above pre-industrial levels, a United Nations-endorsed threshold to avoid the worst consequences of climate change.
National pledges ahead of the Paris conference are so far on track to leave temperature rises at 3 degrees Celsius, according to UN officials.
Mexico City, New York, San Francisco, Vancouver and the regions around Kathmandu and Manchester, England, were among the new signatories to the "Under 2 MOU" agreement launched last year, whose existing participants include Los Angeles.
While designed as a regional movement, three countries also joined the declaration -- Italy, Luxembourg and The Netherlands.
California Governor Jerry Brown vowed that "no opposition, however well-financed" would stop his climate goals, after his drive to mandate lower gas consumption was recently gutted.
"The politics of the future is to create the conditions of a livable, sustainable home," Brown, quoting Pope Francis on climate change, told a signing ceremony at The New School in New York. With the pledges, 38 jurisdictions that cover $8.7 trillion in GDP have now signed the declaration, larger than any country except the United States and China, according to Brown`s office.
The signatories promise, although without binding penalties, to reduce greenhouse gas emissions by 80 to 95 percent from 1990 levels by 2050.
Jeffrey Sachs, a prominent economist and UN adviser on development, said that cities and regions played a critical role in fighting climate change by making decisions on pivotal issues including infrastructure and building codes.
"I think the US is the perfect case -- a country where politics at the national level have been log-jammed for two decades but a tremendous amount is happening at the local and state level," he told AFP.
"And what is actually happening is also becoming a model for national and international policy."
Still, the UN conference in Paris will rely on commitments by national governments that have proven elusive in previous negotiations.
Scientists say that the planet must check temperature rises at two degrees Celsius or lower to avoid the worst consequences of climate change, including a growing number of droughts and disasters.Another group of mayors signed a statement that commits more generally to the new UN Sustainable Development Goals, which include a call for action against climate change.
Signatories, some of whom attended a climate meeting initiated by Pope Francis in July, included the mayors of Bogota, Dakar, Johannesburg, Minneapolis, New Orleans, Oslo and Sao Paulo.
Minneapolis Mayor Betsy Hodges said that her city, which has among the coldest winters in the United States, was obliged to act as it was forecast to be especially hard hit by climate change.
"Cities are smaller, we are more nimble, we can try things and if they don`t work, move on," she told AFP.
"And we don`t have the luxury of not moving an agenda forward on behalf of the people we represent because we see them at the grocery store the next day."
President Barack Obama has made climate change a signature priority but calls to cut emissions have faced intense opposition from the rival Republican Party, many of whose members are friendly with the fossil fuel industry.