Efforts to combat climate change are improving, but still not enough, the new report says. Photo: I. NOYAN YILMAZ/SCIENCE PHOTO LI via AFP
Promises made by governments to cut emissions have edged closer to the goal of keeping heating within 1.5C, but is not enough, a new report has found.
The UN described progress as "baby steps", calling for a "surge" in action at the next global climate summit which begins in two weeks.
The result of the UN synthesis report of all so-called NDCs - country's climate pledges, or Nationally Determined Contributions - was slightly better than last year.
As of September, if governments met their climate pledges, emissions would be 8.8 percent higher in 2030 than they were in 2010. Last year the equivalent figure was 10.6 percent.
To put it another way, the world is currently planning to use up 87 percent of the carbon budget it has left for staying inside 1.5C before 2030, leaving it only the equivalent of two years' worth of current emissions to use after 2030 and still limit heating to 1.5C.
Scientists have warned that every fraction of a degree hotter greatly worsens financial damage and loss of lives from floods, droughts, heatwaves and other disasters.
It was possible the planet could top the 1.5C target temporarily, but still bring average temperatures back down to that level, long-term, by sucking some of that carbon back in.
UN Climate Change executive secretary Simon Stiell said in a statement that countries attending the meeting in Dubai "must not only agree what stronger climate actions will be taken, but also start showing exactly how to deliver them".
The next round of climate action plans was due by 2025.
The latest round-up included promises made by 168 countries, covering the vast bulk of global emissions.
Nine in 10 pledges covered methane as well as carbon dioxide, and a slightly smaller but similar proportion covered nitrous oxide.
The top panel on climate change, the Intergovernmental Panel on Climate Change (IPCC), found emissions need to fall by 43 percent by 2030 compared to the 2019 level to limit temperature rise to 1.5C by the end of this century and avoid the worst impacts of climate change.
As things stood, based on current government promises, emissions would peak before the end of this decade before dipping, but not fast enough to meet global targets, the UN concluded.
However it was possible countries would under- or over-perform their NDCs.
One of the principles of the global Paris Agreement on climate action was ratcheting up the ambition of pledges at successive summits, as well as holding each other to account on progress at meeting promises. This year's discussions will include a stocktake of how countries are doing at delivering on pledges.
The UN synthesis report said the best estimate of peak temperature this century was somewhere in the range of 2.1-2.8C hotter than before the world embraced fossil fuels, depending on the underlying assumptions, highlighting a significant gap from the goal of 1.5C or maximum 2C.
A second UN report released overnight looked at countries' plans to transition to net-zero emissions by or around mid-century. Seventy-five countries had made net-zero promises, including New Zealand, and if they all implemented their strategies on time, greenhouse gas emissions could be roughly 63 percent percent lower in 2050 than in 2019.
Countries representing 77 percent of global emissions had signed up to net-zero pledges. But the UN report noted many of these net-zero targets were uncertain and postponed into the future critical action that needed to take place now.