Media release

From: World Meteorological Organization (WMO)

WMO release:

Greenhouse gas concentrations surge again to new record in 2023

• CO₂ concentrations have increased 11.4 % in just 20 years
• Long lifetime of CO₂ in atmosphere locks in future temperature increase
• El Niño and vegetation fires fuel surge in later part of 2023
• Effectiveness of carbon sinks like forests  cannot be taken for granted
• Improved understanding of carbon-climate feedbacks is needed

Geneva (WMO) - Greenhouse gas levels surged to a new record in 2023, committing the planet to rising temperatures for many years to come, according to a report from the World Meteorological Organization (WMO). Carbon dioxide (CO₂) is accumulating in the atmosphere faster than any time experienced during human existence, rising by more than 10% in just two decades.

In the course of 2023, large vegetation fire CO₂ emissions and a possible reduction in carbon absorption by forests combined with stubbornly high fossil fuel  CO₂ emissions from human and industrial activities to drive the increase, according to the WMO’s annual Greenhouse Gas Bulletin.

The globally-averaged surface concentration of CO₂ reached 420.0 parts per million (ppm), methane 1 934 parts per billion and nitrous oxide 336.9 parts per billion (ppb) in 2023. These values are 151%, 265% and 125% of pre-industrial (before 1750) levels, it said. These are calculated on the basis of the long-term observations within the Global Atmosphere Watch network of monitoring stations.

“Another year. Another record. This should set alarm bells ringing among decision makers. We are clearly off track to meet the Paris Agreement goal of limiting global warming to well below 2°C and aiming for 1.5°C above pre-industrial levels. These are more than just statistics. Every part per million and every fraction of a degree temperature increase has a real impact on our lives and our planet,” said WMO Secretary-General Celeste Saulo.

The 2023 increase of CO₂ in the atmosphere was higher than that of 2022, although lower than that of the three years before that. The annual increase of 2.3 ppm marked the 12th consecutive year with an increase greater than 2 ppm.

The WMO Greenhouse Gas Bulletin is one of WMO’s flagship publications released to inform the UN Climate Change conference, COP, and is now in its 20th issue. During that time the CO₂ level has increased by 11.4 % (42.9 ppm) above the level of 377.1 ppm recorded in 2004 by WMO’s Global Atmosphere Watch network of monitoring stations.

The Greenhouse Gas Bulletin reports on greenhouse gas concentrations, rather than on emission levels. Analysis of data shows that just under half of CO₂ emissions remain in the atmosphere. Just over one quarter are absorbed by the ocean and just under 30% by land ecosystems – although there is considerable year-to-year variability in this because of naturally occurring phenomena like El Niño and La Niña.

The Greenhouse Gas Bulletin complements the UN Environment Programme’s Emissions Gap report. Both were published ahead of COP29 in Baku, Azerbaijan.

During El Niño years, greenhouse gas levels tend to rise because drier vegetation and forest fires reduce the efficiency of land carbon sinks.

“The Bulletin warns that we face a potential vicious cycle. Natural climate variability plays a big role in  carbon cycle. But in the near future, climate change itself could cause ecosystems to become larger sources of greenhouse gases. Wildfires could release more carbon emissions into the atmosphere, whilst the warmer ocean might absorb less CO₂ . Consequently, more CO₂ could stay in the atmosphere to accelerate global warming. These climate feedbacks are critical concerns to human society,” said WMO Deputy Secretary-General Ko Barrett.

From 1990 to 2023, radiative forcing – the warming effect on our climate - by long-lived greenhouse gases increased by 51.5%, with CO2 accounting for about 81% of this increase, according to the National Oceanic and Atmospheric Administration Annual Greenhouse Gas Index cited in the WMO Bulletin.

As long as emissions continue, greenhouse gases will continue accumulating in the atmosphere leading to global temperature rise. Given the extremely long life of CO₂ in the atmosphere, the temperature level already observed will persist for several decades even if emissions are rapidly reduced to net zero.

The last time the Earth experienced a comparable concentration of CO₂ was 3-5 million years ago, when the temperature was 2-3°C warmer and sea level was 10-20 meters higher than now.

Carbon Dioxide

CO₂ is the single most important greenhouse gas in the atmosphere related to human activities, accounting for approximately 64% of the warming effect on the climate, mainly because of fossil fuel combustion and cement production.

The 2023 increase of CO2 in the atmosphere was higher than that of 2022, although lower than that of the three years before that. The annual increase of 2.3 ppm marked the 12^th consecutive year with an increase greater than 2 ppm, while the increase within the year 2023 was one of the largest (2.8 ppm).
The long-term CO₂ increase is due to fossil fuel combustion but there are year-to-year variations due to the El Niño–Southern Oscillation, which impacts photosynthetic CO₂ uptake, respiratory release, and fires. In May 2023, Earth transitioned from a 3-year long La Niña to El Niño.

In 2023, global fire carbon emissions were 16 % above average, seventh amongst all fire seasons since 2003. Canada experienced its worst wildfire season on record. Australia experienced its driest three-month period on record in 2023 from August to October, with severe bushfires.

Methane

Methane is a powerful greenhouse gas which remains in the atmosphere for about a decade.
Methane accounts for about 16% of the warming effect of long-lived greenhouse gases. 
Approximately 40% of methane is emitted into the atmosphere by natural sources (for example, wetlands and termites), and about 60% comes from anthropogenic sources (for example, ruminants, rice agriculture, fossil fuel exploitation, landfills and biomass burning).

The growth in atmospheric methane in 2023 was smaller than 2022 – but was record high for the five-year period. Detailed analysis indicates an emission increase from sources such as wetlands and agriculture, which could at least partly be due to on-going climate feedback that further increases greenhouse gas emissions from the natural systems.

Nitrous Oxide

Nitrous Oxide is both a powerful greenhouse gas and ozone depleting chemical. It accounts for about 6% of the radiative forcing by long-lived greenhouse gases.

N₂O is emitted into the atmosphere from both natural sources (approximately 60%) and anthropogenic sources (approximately 40%), including oceans, soils, biomass burning, fertilizer use, and various industrial processes.

For nitrous oxide, the increase from 2022 to 2023 was lower than that observed from 2021 to 2022, which was the highest increase observed in our modern time record.

The World Meteorological Organization is the United Nations System’s authoritative voice on Weather, Climate and Water

Notes to Editors

The WMO Global Atmosphere Watch Programme coordinates systematic observations and analysis of greenhouse gases and other atmospheric constituents. Greenhouse gas measurement data are archived and distributed by the World Data Centre for Greenhouse Gases (WDCGG) at the Japan Meteorological Agency.

A separate and complementary Emissions Gap Report by UN Environment was released on 24 November. The Emissions Gap report assesses the latest scientific studies on current and estimated future greenhouse gas emissions; they compare these with the emission levels permissible for the world to progress on a least-cost pathway to achieve the goals of the Paris Agreement. This difference between “where we are likely to be and where we need to be” is known as the emissions gap.

UN Climate Change release:

Tomorrow (Monday 28 October) UN Climate Change will release the 2024 Nationally Determined Contributions (NDC) Synthesis Report.

The report assesses the combined impact of nations’ current national climate plans (NDCs) on expected global emissions in 2030, among other measures.

Under embargo until Monday 28 October 10:00 a.m. Bonn CET, please find:

• The near-final version of the report, which can be downloaded at this link. Please note that the report is subject to some minor tweaking and/or cosmetic edits ahead of official launch.

• Below in this email a written statement on the report from Simon Stiell, UN Climate Change Executive Secretary, noting it must mark a "turning point, ending the era of inadequacy and sparking a new age of acceleration", with much bolder new plans from all nations next year.

Key takeouts include: 

• Current NDCs combined would see global emissions in 2030 at a level only 2.6 per cent lower than in 2019 (For reference, last year's NDC Synthesis Report showed combined NDCs leading to global emissions in 2030 at a level 2.0 per cent lower than in 2019).

• This falls far short of the 43% reduction by 2030 that is required to avert the worst impacts of climate change, on the way to net-zero emissions by 2050, according to the Intergovernmental Panel on Climate Change (IPCC).

• With countries currently working on new NDCs due next year, this year’s report shows only marginal progress from last year, and only a fraction of what is expected – and urgently needed – next year, as the Executive Secretary notes in his statement below.

Executive Secretary Simon Stiell
UN Climate Change

Statement on the 2024 NDC Synthesis Report

Embargoed until Monday 28 October
4:00 a.m. New York / 9:00 a.m. London / 10:00 a.m. Bonn

Today’s NDC Synthesis Report must be a turning point, ending the era of inadequacy and sparking a new age of acceleration, with much bolder new national climate plans from every country due next year.

The report’s findings are stark but not surprising – 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.

By contrast, 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.

Bolder new climate plans are vital to drive stronger investment, economic growth and opportunity, more jobs, less pollution, better health and lower costs, more secure and affordable clean energy, among many others benefits.

As expected, with countries currently working to put together new NDCs due next year, this year’s report shows only fractional progress compared to what is expected – and urgently needed – next year.

Current plans combined – if fully implemented – would see emissions of 51.5 gigatonnes of CO2 equivalent in 2030 - a level only 2.6 per cent lower than in 2019. Greenhouse gas pollution at these levels will guarantee a human and economic trainwreck for every country, without exception.

The Intergovernmental Panel on Climate Change notes that greenhouse gas emissions need to be cut 43% by 2030, compared to 2019 levels. By 2035, net global greenhouse gas emissions need to be cut by 60% compared to 2019 levels. This is critical to limiting global heating to 1.5°C this century to avert the worst climate impacts. Every fraction of a degree matters, as climate disasters get rapidly worse.

The next round of national climate plans must deliver a dramatic step up in climate action and ambition.

While these plans are not one-size-fits-all, and are nationally determined, they all need to pass the ABC test:

They must have ambitious new emissions targets that are economy-wide, covering all greenhouse gases, keeping 1.5 degrees alive.

They must be broken down into sectors and gases.

And they must be credible, backed up by substantive regulations, laws, and funding to ensure goals are met and plans implemented.

New NDCs should also detail adaptation priorities and investments to protect critical sectors, infrastructure and people from climate impacts, and support and align with National Adaptation Plan processes.

They should have a time horizon to 2035, with much stronger 2030 targets to drive the deep emissions cuts needed globally this decade.

UN Climate Change – working closely with the wider UN system – is providing a range of practical support, particularly for vulnerable and developing countries, recognizing the severe capacity-constraints and other headwinds that many face.

As these new national climate plans will be among the most important policy documents so far this century, therefore UN Climate Change will deliver a series of events next year to support countries delivery of NDCs and engage the global public in the conversation about their delivery. Further details will be announced at COP29.

COP29 is a vital moment in the world’s climate fight, and today’s data is a blunt reminder of why COP29 must stand and deliver.

Governments must come to Baku ready to convert the pledges in the UAE Consensus at COP28 –  tripling renewables, the global goal on adaptation, transitioning away from all fossil fuels – into real-world, real-economy results, protecting people and their livelihoods everywhere.

COP29 must be an enabling COP, delivering concrete and ambitious outcomes on climate finance that take account of developing country needs, recognizing that such support is core business to protect every nation and the global economy from rampaging climate impacts.

The last generation of NDCs set the signal for unstoppable change. New NDCs next year must outline a clear path to make it happen – by scaling up renewable energy, strengthening adaptation and accelerating the transition to low-carbon economies everywhere.