LONDON, Oct 26 (Reuters) - Current commitments to cut greenhouse gas emissions put the planet on track for an average 2.7 degrees Celsius temperature rise this century, a United Nations report said on Tuesday (Oct 26), in another stark warning ahead of crunch climate talks.

Governments will be in the spotlight at the COP26 conference next week to meet a deadline of this year to commit to more ambitious cut pledges, in what could be the last chance to put the world on track to limiting warming to below 2 degrees Celsius above pre-industrial levels and ideally to 1.5 degrees Celsius.

As extreme weather events from wildfires to floods have hit countries around the world, a UN report in August warned that global warming due to greenhouse gas emissions could breach 1.5 degrees Celsius in the next two decades.

British Prime Minister Boris Johnson said on Monday it was "touch and go" whether the most important round of UN talks since the Paris Agreement in 2015 will secure the agreements needed to tackle climate change.

And the UN World Meteorological Organization said ahead of the two-week event that begins in Glasgow, Scotland on Sunday that greenhouse gas concentrations hit a record last year and the world is "way off track" in capping rising temperatures.

The annual "emissions gap" report by the United Nations' Environment Programme (UNEP), which measures the gap between anticipated emissions and those consistent with limiting the temperature rise this century as agreed in the Paris accord, said updated pledges only reduce forecast 2030 emissions by an additional 7.5 per cent, compared to the previous commitments.

If continued throughout this century, this would lead to warming of 2.7 degrees Celsius, slightly less than the 3 degrees Celsius UNEP forecast in its last report. A 30 per cent cut is needed to limit warming to 2 degrees Celsius and a 55 per cent cut is needed to limit to 1.5 degrees Celsius.

It said current commitments to net zero could limit warming to around 2.2 degrees Celsius by the end of the century, but 2030 pledges so far do not put major emitters on a clear path to this.

As a group, G20 countries, which represent 80 per cent of global emissions, are not on track to achieve their original or new 2030 pledges.

"If there is no meaningful reduction of emissions in the next decade, we will have lost forever the possibility to reach 1.5 degrees," UN Secretary General Antonio Guterres told a press briefing.

"It is absolutely essential that all G20 countries present before Glasgow or in Glasgow (pledges) that are compatible with 1.5 degrees Celsius," he added.