Biggest economies fail to slow global warming

The world’s major economies, many of which helped to fuel Earth’s warming over the past century through massive greenhouse gas pollution, are still failing to do their part to adequately tackle the problem, a new United Nations report says.

The annual UN emissions gap report details how the Group of 20 – comprised of 19 individual nations and the European Union – are not on track to meet the emissions-cutting pledges they made as part of the 2015 Paris agreement, or the updated plans some countries have submitted ahead of high-profile climate talks next month in Scotland.

As developed nations account for roughly three-quarters of global greenhouse gas emissions, their failures to set bold targets or to fully meet existing goals are a significant reason why the world remains on a path towards worsening climate catastrophes, the UN found.

‘‘We’re just so far off track, it’s really discouraging,’’ said Drew Shindell, an earth science professor at Duke University in the United States and a co-author of the report.

He said that while some countries were moving with more urgency, those efforts would lead to only ‘‘minimal change this decade’’ unless major emitters made significant changes soon.

But despite the substantial gap that remains between emissions and how much they must shrink to live up to the aspirations set six years ago in Paris, the report does cite evidence of progress.

Some key nations such as the US, Canada and the EU have outlined new, stronger climate plans, which if implemented would result in sharp cuts to their emissions by the end of this decade. Other large emitters, such as China and India, have not yet formally submitted new plans, but have announced domestic targets such as greenhouse gas emissions peaking by 2030 or installing colossal amounts of renewable energy, respectively.

Still, the report finds that the profound transformation away from fossil fuels is not happening nearly as fast as scientists have said is essential.

‘‘We’re not bending the curve as much as we should,’’ said Inger Andersen, executive director of the UN Environment Programme. ‘‘We need to get much more ambitious.’’

The UN report estimates that new commitments from about 120 nations, as of the end of September, could result in a 7.5 per cent cut to the world’s greenhouse gas emissions by 2030 if fully implemented.

But emissions would actually need to fall about seven times that fast to hit the most lofty goal of the Paris agreement – limiting Earth’s warming to 1.5 degrees C above pre-industrial levels. To remain at no more than 2C of warming, the report found, would require cutting greenhouse gas pollution about four times as fast as current plans outline.

The report says dozens of countries have pledged to reach ‘‘net zero’’ emissions by 2050. But many of those long-term plans are ‘‘vague’’ and ‘‘incomplete’’, the authors say, and don’t detail nearterm actions that would actually put nations on a track to achieve such promises.

■ Scott Morrison has accused critics of his 2050 net-zero plan of not understanding Australia as pressure grows over climate change action.

The Australian prime minister yesterday defended his government’s path to 2050, which relies 85 per cent on existing technology and 15 per cent on new breakthroughs.

A chorus of international and domestic critics, including Sir David Attenborough, have blasted the plan for lacking detail and failing to increase 2030 emissions reduction targets.

Morrison rejected the barrage of disapproval, saying it came from people who wanted to tax, regulate and shut industries down. ‘‘But I will do what is right for Australia, and we are getting results,’’ he said.