Pace of CO2 Accumulation in Earth's Air Slows in February 2025

The pace at which carbon dioxide is accumulating in the Earth’s atmosphere slowed in February 2025 after peaking in January 2025.

The change comes as the first significant decline since the period from December 2022 through January and February 2023, which marked the end of China’s “zero-COVID” lockdowns. The end of China’s restrictions initiated a massive surge in carbon dioxide emissions, which rocketed up in during the following two years.

The initial surge in 2023 was prompted by China’s lifting of its repressive policy and the reopening of its economy. That recovery proved to be weak however, so China’s government instituted policies to stimulate its economy in late 2023 and in 2024, which propelled the nation’s carbon dioxide emissions to new heights.

Two recent headlines emphasize the extent to which the policies of China’s government contributed to carbon dioxide emissions. The first headline is from September 2024, the second from February 2025:

• China’s coal use and output are rising, even as renewables surge
• China’s construction of new coal-power plants ‘reached 10-year high’ in 2024

Since China was already, by far and away, the world’s largest source of carbon dioxide emissions, China’s government’s stimulus policies greatly contributed to the surge of carbon dioxide emissions during 2024.

The following chart illustrating the trailing year average of the year-over-year change in the concentration of atmospheric carbon dioxide measured at the remote Mauna Loa Observatory shows that two-year-long increase to a record high for the modern era, along with February 2025′s decline:

Carbon Brief, the source of the second headline, provides more information about the policies that contributed the most to the increase of CO₂ in the Earth’s air during the preceding 12 months:

Construction started on 94.5GW of new coal-fired power plants in 2024, according to the study. It says this is a sign of continued momentum in developing new coal projects, despite government pledges to “strictly” control the use of the fossil fuel. The report adds that 3.3GW of suspended projects also resumed construction in 2024.

Approvals for new coal construction rebounded in the second half of the year to 66.7GW, after permitting only 9GW in the first half.

Taken altogether, the report says this signals a substantial amount of new capacity will come online in the next few years, “solidifying” coal’s place as a major source of electricity.

China’s government will miss all of the CO₂ emissions targets it claimed it was going to hit in 2025.

References

National Oceanographic and Atmospheric Administration. Earth System Research Laboratory. Mauna Loa Observatory CO2 Data. [Online Data]. Updated 5 March 2025.

Image Credit: Microsoft Copilot Designer.. Prompt: “A diagram showing a coal power plant emitting carbon dioxide. The power plant has the Chinese characters for 煤 (coal) written on it.”