By Matthew Green
LONDON (Reuters) - Pledges made so far under the 2015 Paris accord would deliver less than a 1% reduction in global greenhouse gas emissions by 2030 -- a fraction of the 45% cut needed to avert catastrophic climate change, according to a U.N. report published on Friday.
The tally underscored the challenge negotiators face as they try to secure more ambitious commitments from big polluters ahead of a climate conference in Glasgow in November that is seen as the most important since the Paris deal was signed.
"While we acknowledge the recent political shift in momentum towards stronger climate action throughout the world, decisions to accelerate and broaden climate action everywhere must be taken now," said U.N. climate chief Patricia Espinosa.
The report aimed to provide governments with a stock take on progress in implementing the Paris deal by the almost 200 countries that adopted it five years ago.
It found that 75 parties, jointly representing about 30% of the world's greenhouse gas emissions, had submitted new or revised emissions plans by Dec. 31. These included European Union countries and nations such as Britain, Japan, Mexico, Brazil and Australia.
If implemented, the combined impact of these pledges would be to shave less than 1% off global emissions by the end of this decade compared to 2010 levels.
Scientists say emissions must fall by about 45% by 2030 to limit the rise in average global temperatures to 1.5 degrees Celsius -- the most ambitious Paris goal.
Major polluters such as China, the United States, and India have yet to unveil revised pledges ahead of the conference, leaving open the possibility that strong commitments from these and other countries could still improve the outlook.
"This is a status report. It's weak but there are many big emitters who can significantly change the picture this year," said Christiana Figueres, an architect of the Paris deal and co-founder of Global Optimism, a network promoting climate action.
(Reporting by Matthew Green; Editing by Frances Kerry)