Pledges made so far under the 2015 Paris accord would deliver less than a one percent reduction in global greenhouse gas emissions by 2030 - a fraction of the 45 percent cut needed to avert catastrophic climate change, according to a UN 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...