Global emissions must drop at least 4% annually to meet Paris goals: UN report

Failure to strengthen and start delivering immediately upon commitments made under the Paris Agreement on climate change will put the world on track for a global temperature increase of between 2.6 and 3.1 degrees Celsius by the end of the century, according to a new UN report.

"This would bring debilitating impacts to people, planet and economies," the UN Environment Program warned in its annual Emissions Gap Report released Oct. 24.

The UN's 2024 report comes as signatories to the Paris Agreement prepare to gather in Baku, Azerbaijan, next month for the UN Climate Change Conference, known as COP29.

Following the conference, participants must submit revised nationally determined contribution, or NDC, pledges for 2035 by February 2025. In 2021, the US pledged to reduce economywide greenhouse gas emissions by 50% to 52% from 2005 levels by 2030 as part of its renewed membership in the global Paris Agreement.

The UN said in its latest report that "it remains technically possible" for the world to achieve a 1.5-degree C pathway consistent with the Paris Agreement's underlying goals, which aim to avoid catastrophic climate impacts. The 1.5-degree pathway calls for achieving net-zero global greenhouse gas emissions by midcentury.

"To deliver on this potential, sufficiently strong NDCs would need to be backed urgently by a whole-of-government approach, measures that maximize socioeconomic and environmental co-benefits, enhanced international collaboration that includes reform of the global financial architecture, strong private sector action and a minimum six-fold increase in mitigation investment," the report said.

The report said G20 nations -- the world's largest-emitting members -- need to do "the heavy lifting."

The report cited earlier accounts indicating that annual global greenhouse gas emissions increased to a record 57.1 gigatons in 2023, or 1.3% from 2022 levels. G20 members accounted for 77% of those emissions, with the six largest emitters accounting for 63% of total global emissions, according to the UN report. The least-developed countries accounted for only 3% of global emissions in 2023.

Annual emissions for seven G20 members -- China, India, Indonesia, Mexico, Saudi Arabia, South Korea and Turkey -- have yet to peak.

"Peaking [greenhouse gas] emissions is a prerequisite to achieving net-zero," the report said.

The report noted that the rate of decarbonization for G20 members whose emissions have already peaked needs to accelerate, "in some cases dramatically," after 2030 to achieve their net-zero goals. Those members are Argentina, Australia, Brazil, Canada, the EU, Japan, Russia, South Africa, the UK and the US.

Overall, global greenhouse gas emissions would need to fall by an average of 4% to 7.5% annually until 2035 to stay in line with a 2-degree C or 1.5-degree C pathway, according to the report.

If countries delay pursuing more ambitious NDCs until 2030, required annual emission reductions would rise to between 8% and 15%, the report said.

"This report forcefully confirms that nations' efforts to cut heat-trapping emissions have been grossly insufficient to date," Rachel Cleetus, policy director of the Climate and Energy program at the Union of Concerned Scientists, said in a statement. "Nations' updated emission reduction commitments, which are due by February, must directly respond to the flashing red lights in this report and be followed through by robust policies to meet those commitments."