The rate at which carbon dioxide is accumulating in the Earth's atmosphere slowed in June 2025, reversing a brief uptick in the previous month's data. The change resumes a downward trend that has been in place since the end of 2024.

This period coincides with slowed output within China's economy. Much of this negative change occurred in response to new and expanded tariffs and trade sanctions imposed by the United States. 2024 had seen elevated carbon dioxide emissions arise out of China as the nation's factories rushed to meet orders for goods to beat the clock on the outgoing Biden administration's final trade restrictions and expanding tariffs expected to take effect in January 2025.

In April 2025, the Trump administration rolled out its global tariff program, which continued the downward pressure on China's industrial sector. Reuters describes several of the factors contributing to the nation's reduction in CO₂ emissions:

The latest tariffs imposed by U.S. president Donald Trump on Chinese products have impacted the demand for China-made goods and caused production lines to slow down across a variety of manufactured items.

The overall energy needs of these industries have been reduced by the slower pace on construction sites and production lines in factories. This has allowed power generation companies to reduce their production.

These dynamics have shown up in the pace at which carbon dioxide accumulates in the Earth's atmosphere because China is, by far and away, the world's largest producer of CO₂ emissions. The following chart shows how the trailing twelve month average of the year-over-year change in the concentration of atmospheric carbon dioxide measured at the remote Mauna Loa Observatory has evolved from January 2000 through June 2025:

Because the industrial sector of China's economy has slowed so much since the end of 2024, the reduction of demand for electrical power is expected to reduce China's CO₂ emissions to a "record low". Here's Reuters again:

China's utilities have been able to achieve record-low emissions in the first half of 2025 by focusing on clean energy supplies.

According to the energy portal, electricitymaps.com, carbon dioxide emissions per Kilowatt Hour (kWh) of Electricity averaged 492 Grams during the first half of 2025.

This was the first time a reading under 500 grams per kWh had been recorded. It is also down from 514g/kWh in the same period of 2024, and 539g/kWh between January and June 2023.

With a large portion of its industries running at reduced capacity, China has been able to use a larger share of its renewable energy sources to provide power, reducing its CO₂ emissions by significant amount. Reuters indicates however that an improvement in fortune for China's industrial sector will reverse that achievement:

China's power requirements will rise if the manufacturing and construction sectors recover. This will lead to a return of fossil fuels that emit pollution.

If China's economy is still slowed by the construction debt and the tariff concerns, then the use of fossil fuels could be further reduced, which would lead to further emissions reductions from the power sector.

Carbon dioxide is not the only kind of emission that is being reduced. The reduction of China's economic output during 2020's Coronavirus Pandemic also reduced emissions of aerosols, which a new study indicates contributed to an acceleration of global warming. Here's the abstract from the recently published paper:

Global surface warming has accelerated since around 2010, relative to the preceding half century¹–³. This has coincided with East Asian efforts to reduce air pollution through restricted atmospheric aerosol and precursor emissions₄–₅. A direct link between the two has, however, not yet been established. Here we show, using a large set of simulations from eight Earth System Models, how a time-evolving 75% reduction in East Asian sulfate emissions partially unmasks greenhouse gas-driven warming and influences the spatial pattern of surface temperature change. We find a rapidly evolving global, annual mean warming of 0.07 ± 0.05 °C, sufficient to be a main driver of the uptick in global warming rate since 2010. We also find North-Pacific warming and a top-of-atmosphere radiative imbalance that are qualitatively consistent with recent observations. East Asian aerosol cleanup is thus likely a key contributor to recent global warming acceleration and to Pacific warming trends.

It's not yet clear how economists and environmentalists feel about the role of tariffs operating as a de facto carbon tax that reduces carbon dioxide emissions along with economic activity or to the reduction of the emissions of aerosol pollutants and the resulting cleaner air contributing to global warming.

References

National Oceanographic and Atmospheric Administration. Earth System Research Laboratory. Mauna Loa Observatory CO2 Data. [Online Data]. Updated 14 July 2025.

Samset, B.H., Wilcox, L.J., Allen, R.J. et al. East Asian aerosol cleanup has likely contributed to the recent acceleration in global warming. Commun Earth Environ 6, 543 (2025). DOI: 10.1038/s43247-025-02527-3.

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