Last year was the hottest year for the planet since records began and 2023 also saw the highest levels of greenhouse gases in the atmosphere ever recorded.

The European Union’s Copernicus Climate Change Service (C3S) said the past 12 months have seen records tumble as the world heats up. It saw the hottest month on record and daily global temperature averages briefly surpassing pre-industrial levels by more than 2°C. Unprecedented global temperatures from June onwards led 2023 to become the warmest year on record – overtaking by a large margin 2016, the previous warmest year.

It also become the year with highest concentration of greenhouse gases.

“Greenhouse gas concentrations in 2023 reached the highest levels ever recorded in the atmosphere according to C3S and the Copernicus Atmosphere Monitoring Service (CAMS),” the report added. “Carbon dioxide concentrations in 2023 were 2.4 ppm higher than in 2022 and methane concentrations increased by 11 ppb. For 2023, the annual estimate of the atmospheric concentration of carbon dioxide is 419 ppm, and for methane the concentration is 1902 ppb. The rate of increase of carbon dioxide was similar to the rate observed in recent years. The rate of increase of methane remained high but was lower than in the last 3 years.”

Mauro Facchini, head of Earth Observation at the Directorate General for Defence Industry and Space, European Commission, said: “We knew thanks to the work of the Copernicus programme throughout 2023 that we would not receive good news today. But the annual data presented here provides yet more evidence of the increasing impacts of climate change.

“The European Union, in line with the best available science, has agreed on an emission reduction of 55% by 2030 – now just 6 years away. The challenge is clear. The Copernicus Programme, managed by the European Commission, is one the best tools available to guide our climate actions, keep us on track with the goals of the Paris Agreement and accelerate the green transition.”

Samantha Burgess, deputy Director of the Copernicus Climate Change Service: “2023 was an exceptional year with climate records tumbling like dominoes. Not only is 2023 the warmest year on record, it is also the first year with all days over 1°C warmer than the pre-industrial period. Temperatures during 2023 likely exceed those of any period in at least the last 100,000 years.”

Among the report’s highlights were:

• 2023 is confirmed as the warmest calendar year in global temperature data records going back to 1850.
• 2023 had a global average temperature of 14.98°C, 0.17°C higher than the previous highest annual value in 2016.
• 2023 was 0.60°C warmer than the 1991-2020 average and 1.48°C warmer than the 1850-1900 pre-industrial level.
• It is likely that a 12-month period ending in January or February 2024 will exceed 1.5°C above the pre-industrial level.
• 2023 marks the first time on record that every day within a year has exceeded 1°C above the 1850-1900 pre-industrial level. Close to 50% of days were more than 1.5°C warmer than the 1850-1900 level, and two days in November were, for the first time, more than 2°C warmer.
• Annual average air temperatures were the warmest on record, or close to the warmest, over sizeable parts of all ocean basins and all continents except Australia.
• Each month from June to December in 2023 was warmer than the corresponding month in any previous year.
• July and August 2023 were the warmest two months on record. Boreal summer (June-August) was also the warmest season on record.
• September 2023 was the month with a temperature deviation above the 1991–2020 average larger than any month in the ERA5 dataset.
• December 2023 was the warmest December on record globally, with an average temperature of 13.51°C, 0.85°C above the 1991-2020 average and 1.78°C above the 1850-1900 level for the month.
• average sea surface temperatures (SSTs) remained persistently and unusually high, reaching record levels for the time of year from April through December

The report stated: “The earliest signs of how unusual 2023 was to become began to emerge in early June, when temperature anomalies relative to 1850-1900 pre-industrial level reached 1.5°C for several days in a row. Although this was not the first time daily anomalies had reached this level, this had never previously happened at this time of the year. For the rest of 2023, global daily temperature anomalies above 1.5°C became a regular occurrence, to the point where close to 50% of days in 2023 were in excess of 1.5°C above the 1850-1900 level.

“This does not mean that we have surpassed the limits set by the Paris Agreement (as they refer to periods of at least 20 years where this average temperature anomaly is exceeded) but sets a dire precedent.”

Carlo Buontempo, director of the Copernicus Climate Change Service, explained: “The extremes we have observed over the last few months provide a dramatic testimony of how far we now are from the climate in which our civilisation developed. This has profound consequences for the Paris Agreement and all human endeavours. If we want to successfully manage our climate risk portfolio, we need to urgently decarbonise our economy whilst using climate data and knowledge to prepare for the future.”