Greenhouse gas levels broke records, emissions targets fall short

The World Meteorological Organization (WMO) and UN Climate Change released urgent reports on the escalating levels of greenhouse gasses and the inadequacy of current emissions targets. Both reports underscore the dire need for rapid and aggressive climate policies ahead of COP29, which is set to take place in Baku from Nov 11 to 22.

The WMO reported on Monday that greenhouse gas concentrations reached unprecedented levels in 2023, driving global temperatures higher and committing the planet to years of warming. The UN agency’s annual Greenhouse Gas Bulletin highlighted that carbon dioxide (CO2), methane and nitrous oxide concentrations are all at record highs, with CO2 levels climbing at an alarming rate—up more than 10 percent in just two decades.

CO2 concentrations rose by 11.4 percent in the past 20 years, reaching 420 ppm in 2023. Methane and nitrous oxide levels were also significantly elevated, reaching 1,934 ppb and 336.9 ppb, respectively. These values represent 151 percent, 265 percent, and 125 percent increases from pre-industrial levels, according to the WMO’s Global Atmosphere Watch network of monitoring stations.

“These aren’t just statistics; every part per million and every fraction of a degree of temperature increase brings real impacts on our lives and ecosystems,” said WMO Secretary-General Celeste Saulo. The 2023 CO2 increase was 2.3 ppm—the 12th consecutive year with an increase above two ppm—driven by persistent fossil fuel emissions and aggravated by large-scale vegetation fires and the effects of El Niño.

The report underscores the difficulty in meeting the Paris Agreement goals to limit warming below 2°C, with an aspirational target of 1.5°C above pre-industrial levels. “We are clearly off track,” said Saulo. She stressed that warming feedbacks—where rising temperatures reduce the ability of ecosystems to absorb CO2—pose an even greater risk.

Due to the long atmospheric lifespan of CO2, the current levels of global warming will likely persist for decades, even with rapid emission cuts. “The warming effects of CO2 will not dissipate quickly, locking in temperature increases for generations,” noted Saulo. Radiative forcing—or the warming impact from greenhouse gasses—has increased by 51.5 percent since 1990, with CO2 accounting for 81 percent of this rise.

The WMO report highlighted concerns over the durability of natural carbon sinks. Currently, oceans and land ecosystems absorb nearly half of CO2 emissions, with oceans accounting for a quarter and land ecosystems nearly 30 percent. However, as Deputy Secretary-General Ko Barrett noted, climate change could reduce these natural carbon sinks’ efficiency. “Warming oceans may absorb less CO2, while wildfires could release more carbon into the atmosphere,” Barrett warned, adding that climate feedback could intensify warming further.

The WMO pointed out that current CO2 levels mirror those of 3m-5m years ago, a period when global temperatures were 2-3°C higher and sea levels were 10-20 meters above today’s levels. With the WMO warning that ecosystems themselves might soon become net emitters of greenhouse gasses, Barrett stressed the urgency of addressing these “vicious cycles” that could exacerbate the crisis and have profound impacts on human society.

These findings align with the UN Environment Program’s recent Emissions Gap Report, which assesses the growing disparity between current emissions and levels needed to meet climate targets.

On Monday, UN Climate Change released its 2024 Nationally Determined Contributions (NDC) Synthesis Report. The report evaluates the collective impact of current national climate plans on anticipated global emissions by 2030, underscoring the critical changes required to avert severe climate impacts. 

UN Climate Change Executive Secretary Simon Stiell emphasizes that this report “must mark a turning point, ending the era of inadequacy and sparking a new age of acceleration” with much bolder climate plans needed from all nations in the coming year. 

The report finds that combined global NDCs would lead to a mere 2.6 percent reduction in emissions by 2030 from 2019 levels, only marginally improving on last year’s two percent projection. This falls far short of the 43 percent reduction by 2030 needed to limit global warming to 1.5°C, as advised by the Intergovernmental Panel on Climate Change (IPCC).

Stiell states, “Current national climate plans fall miles short of what’s needed to stop global heating from crippling every economy and wrecking billions of lives and livelihoods across every country.” He emphasizes that “much bolder new national climate plans can not only avert climate chaos—done well, they can be transformational for people and prosperity in every nation.”

The report serves as a wake-up call, highlighting that “emissions of 51.5 gigatonnes of CO2 equivalent in 2030—only 2.6 percent lower than in 2019—will guarantee a human and economic train wreck for every country.” 

Stiell urges nations to adopt “ambitious new emissions targets that are economy-wide” and ensure they are backed by “substantive regulations, laws, and funding to ensure goals are met and plans implemented.” He also emphasizes the need for new NDCs to detail adaptation priorities and investments to protect vulnerable sectors and populations.

With COP29 in Baku on the horizon, Stiell stresses the importance of converting commitments from COP28, such as transitioning from fossil fuels and tripling renewables, into concrete policies. He concludes that new NDCs will be among “the most important policy documents” of the century, setting a clear path for renewable energy scaling, strengthened adaptation, and accelerated low-carbon transitions globally.

Both reports aim to inform COP29 discussions, where decision-makers are urged to treat the surging greenhouse gas levels as a “wakeup call” and to adopt more aggressive climate policies.