The world is on track to hit 2.7 degrees Celsius of warming by 2100 despite stronger emissions reduction targets, the United Nations has said on the eve of global climate talks.
The annual UN Emissions Gap report, released today, compares our current trajectory with where we need to be to keep warming to well below 2C, as per the Paris Agreement.
Despite 120 countries strengthening their emissions reduction targets as of September 30 this year, the report authors said this was still not enough to avoid dangerous warming.
To get on the "least cost pathway" to limiting warming to between 1.5C and 2C, they said the targets needed to cut a further 28 gigatonnes of greenhouse gases per year, beyond that pledged by the current 2030 commitments.
This effectively amounted to halving global greenhouse gas emissions by 2030, the authors said.
The report projected 2021 emissions had bounced back to just shy of 2019's record levels.
But Mark Howden from the Australian National University's Climate Change Institute said the data used was a few months old and he thought 2021 emissions would actually hit a new record high.
"It's a bit sad, but I think they've actually understated it," Professor Howden said.
"We've seen a firming up of emissions that are going to be higher post-COVID than before."
A separate report from the UN's World Meteorological Organization (WMO), released yesterday, found that global average atmospheric greenhouse gas concentrations hit a record high of 413.2 parts per million in 2020 — higher than at any other time in the past 2 million years.
Today's report comes as countries prepare to head to the COP26 climate summit in Glasgow, which has been dubbed the world's "last best chance" to cap warming below 1.5-2C.
"There was still hope that COP26 could become a turning point on climate action," the authors wrote.
According to the report, 120 countries responsible for 51 per cent of greenhouse gas emissions had submitted new nationally determined contributions (NDCs) ahead of Glasgow.
Despite the shortfall in the commitments, the authors said if all countries kept their net-zero pledges and brought their 2030 targets in line with those pledges, that could potentially shave a further 0.5C off warming this century.
COP26 will be a huge test for the mechanisms put in place under the Paris Agreement and the world's capacity to keep 1.5C of warming within reach, according to Wes Morgan, a researcher with the Climate Council and a research fellow with the Griffith Asia Institute.
The initial targets set by each country at Paris in 2015 had the world on track for warming of 3C, Dr Morgan said.
"But Paris set up a process where we'd come together every five years to set new targets — that's what's called a ratchet mechanism."
"What gives you hope is that over the last 18 months 120-plus countries have pledged to achieve net zero by 2050. That now covers more than half the global economy and that sends a huge market signal."
Prime Minister Scott Morrison committed Australia to a target of net-zero emissions by 2050 on Tuesday.
COVID green recovery falling short
Global annual emissions dropped 5.4 per cent in 2020.
However, greenhouse gas emissions are cumulative, and the COVID-19 downturn has made barely a ripple in slowing warming, Professor Howden said.
"People ask does the reduction in emissions during COVID make much difference in terms of emissions projections?
"We got the behavioural change, but we didn't get the structural change."
Professor Howden said many, many researchers and analysts suggested that stimulating economic recovery post-COVID-19 could help fuel a transition to low-carbon infrastructure.
However, according to the Emissions Gap report, between just 17-19 per cent of total recovery investments to May 2021 had been spent on projects that would lead to a reduction in greenhouse gas emissions.
The lowest spending had been typically in low-income countries.
The opportunity to lead a post-COVID-19 green recovery is being squandered and studies have found that investment in fossil fuels has actually increased, Professor Howden said.
While much attention will be on emissions reduction pledges and net-zero targets at COP26, Professor Howden said there were other important negotiations taking place, including financial commitments to help developing countries transition to low-carbon economies and to build resilience.
"Then there's the agendas around the global emissions trading market and ensuring effective rules there," he said.
Well-regulated carbon trading schemes, for instance, can ensure developing countries are financially rewarded for conserving ecosystems such as rainforests, which act as carbon sinks.
Australia's own Pacific neighbours are some of those that stand to be worst hit by climate change, and form a strong voting block within the UN, Dr Morgan said.
"Pacific Island countries — their slogan is '1.5 to stay alive' — they see Glasgow as something of a last-ditch in their struggle for staying below that threshold.
"It will be the Pacific island countries and major powers like the US and UK working together to heap pressure on the laggards, and that includes Australia."
Ahead of COP26, United States special presidential envoy for climate John Kerry has been pushing for more countries to increase their emissions reduction targets.
Speaking from Saudi Arabia on Monday, Mr Kerry said the challenge to decarbonise was not about politics or ideology, but science, and that we needed to accelerate our efforts over the next few years.
"This is the biggest market opportunity the world has ever known," Mr Kerry said.
"It's the biggest transformation that has ever taken place on this planet since the industrial revolution, if we do it."
