Pep Canadell, CSIRO; Corinne Le Quéré, University of East Anglia; Glen Peters, Center for International Climate and Environment Research – Oslo; Judith Hauck, Universität Bremen; Julia Pongratz, Ludwig Maximilian University of Munich; Philippe Ciais, Commissariat à l’énergie atomique et aux énergies alternatives (CEA); Pierre Friedlingstein, University of Exeter; Robbie Andrew, Center for International Climate and Environment Research – Oslo, and Rob Jackson, Stanford University

Global emissions of fossil carbon dioxide (CO₂), in yet another year of growth, will increase by 1.1% in 2023. These emissions will hit a record 36.8 billion tonnes. That’s the finding of the Global Carbon Project’s 18th annual report card on the state of the global carbon budget, which we released today.

Fossil CO₂ includes emissions from the combustion and use of fossil fuels (coal, oil and gas) and cement production. Adding CO₂ emissions and removals from land-use change, such as deforestation and reforestation, human activities are projected to emit 40.9 billion tonnes of CO₂ in 2023.

The world’s vegetation and oceans continue to remove about half of all CO₂ emissions. The rest builds up in the atmosphere and is causing increasing warming of the planet.

At current emission levels, the remaining carbon budget for a one-in-two chance to limit warming to 1.5°C will likely be exceeded in seven years, and in 15 years for 1.7°C. The need to cut emissions has never been so urgent.

Emissions from every fossil source are up

Fossil CO₂ emissions now account for about 90% of all CO₂ emissions from human activities. Emissions from every single fossil source increased this year compared to 2022:

• coal (41% of global CO₂ emissions) up 1.1%
• oil (32%) up 1.5%
• natural gas (21%) up 0.5%
• cement (4%) up 0.8%.

Although global emissions have increased, the picture for individual countries is more diverse. There are some signs of progress towards decarbonisation.

China’s emissions (31% of the global total) increased by 4% with growth in all fossil fuel sources. The highest relative growth was from oil emissions. This was in part due to the transport sector’s recovery after COVID-19 pandemic shutdowns.

The United States’ emissions (14% of global) are down by 3%. The rapid retirement of coal-fired power plants drove most of this decline. US coal emissions are the lowest since 1903.

India’s emissions (8% of global) increased by 8.2%. Emissions for all fossil fuels grew by 5% or more, with coal the highest at 9.5%. India is now the world’s third-largest fossil CO₂ emitter.

European Union emissions (7% of global) are down by 7.4%. This decline was due to both high renewable energy penetration and the impacts on energy supply of the war in Ukraine.

During the decade of 2013-2022, 26 countries had declining fossil CO₂ emission trends while their economies continued to grow. The list includes Brazil, France, Germany, Italy, Japan, Portugal, Romania, South African, United Kingdom and USA.

Total CO₂ emissions are near a peak

While fossil CO₂ emissions continue to increase, net emissions from land-use change, such as deforestation (CO₂ source), minus CO₂ removals, such as reforestation (CO₂ sink), appear to be falling. However, estimates of emissions from land-use change are highly uncertain and less accurate overall than for fossil fuel emissions.

Our preliminary estimate shows net emissions from land-use change were 4.1 billion tonnes of CO₂ in 2023. These emissions follow a small but relatively uncertain decline over the past two decades.

The declining trend was due to decreasing deforestation and a small increase in reforestation. The highest emitters are Brazil, Indonesia and the Democratic Republic of the Congo. These three countries contribute 55% of net global CO₂ emissions from land-use change.

When we combine all CO₂ emissions from human activities (fossil and land use), we find very little trend in total emissions over the past decade. If confirmed, this would imply global CO₂ emissions from human activities are not growing further but remain at very high record levels.

Stable CO₂ emissions, at about 41 billion tonnes per year, will lead to continuing rapid CO₂ accumulation in the atmosphere and climate warming. To stabilise the climate, CO₂ emissions from human activities must reach net zero. This means any residual CO₂ emissions must be balanced by an equivalent CO₂ removal.

Nature’s a big help, with a little human help

Terrestrial vegetation and ocean absorb about half of all CO₂ emissions. This fraction has remained remarkably stable for six decades.

Besides the natural CO₂ sinks, humans are also removing CO₂ from the atmosphere through deliberate activities. We estimate permanent reforestation and afforestation over the past decade have removed about 1.9 billion tonnes of CO₂ per year.

This is equivalent to 5% of fossil fuel emissions per year.

Other non-vegetation strategies are in their infancy. They removed 0.01 million tonnes of CO₂.

Machines (direct air carbon capture and storage) pulled 0.007 million tonnes of CO₂ out of the atmosphere. Enhanced weathering projects, which accelerate natural weathering processes to increase the CO₂ uptake by spreading certain minerals, accounted for the other 0.004 million tonnes. This is more than a million times smaller than current fossil fuel emissions.

The remaining carbon budget

From January 2024, the remaining carbon budget for a one-in-two chance to limit global warming to 1.5°C has been reduced to 275 billion tonnes of CO₂. This budget will used up in seven years at 2023 emission levels.

The carbon budget for limiting warming to 1.7°C has been reduced to 625 billion tonnes of CO₂, with 15 years left at current emissions. The budget for staying below 2°C is 1,150 billion tonnes of CO₂ – 28 years at current emissions.

Reaching net zero by 2050 requires total anthropogenic CO₂ emissions to decrease on average by 1.5 billion tonnes of CO₂ per year. That’s comparable to the fall in 2020 emissions resulting from COVID-19 measures (-2.0 billion tonnes of CO₂).

Without additional negative emissions (CO₂ removal), a straight decreasing line of CO₂ emissions from today to 2050 (when many countries aspire to achieve net zero CO₂ or the more ambitious net zero for all greenhouse gases) would lead to a global mean surface temperature of 1.7°C, breaching the 1.5°C limit.

Renewable energy production is at a record high and growing fast. To limit climate change fossil and land-use change, CO₂ emissions must be cut much more quickly and ultimately reach net zero.

Pep Canadell, Chief Research Scientist, CSIRO Environment; Executive Director, Global Carbon Project, CSIRO; Corinne Le Quéré, Royal Society Research Professor of Climate Change Science, University of East Anglia; Glen Peters, Senior Researcher, Center for International Climate and Environment Research – Oslo; Judith Hauck, Helmholtz Young Investigator group leader and deputy head, Marine Biogeosciences section a Alfred Wegener Institute, Universität Bremen; Julia Pongratz, Professor of Physical Geography and Land Use Systems, Department of Geography, Ludwig Maximilian University of Munich; Philippe Ciais, Directeur de recherche au Laboratoire des science du climat et de l’environnement, Institut Pierre-Simon Laplace, Commissariat à l’énergie atomique et aux énergies alternatives (CEA); Pierre Friedlingstein, Chair, Mathematical Modelling of Climate, University of Exeter; Robbie Andrew, Senior Researcher, Center for International Climate and Environment Research – Oslo, and Rob Jackson, Professor, Department of Earth System Science, and Chair of the Global Carbon Project, Stanford University

This article is republished from The Conversation under a Creative Commons license. Read the original article.