Used primarily in high-voltage electrical switchgear in electric power grids, sulfur hexafluoride (SF₆) is one of the most potent greenhouse gases on Earth. The GWP of SF₆ is 24,300 that of CO₂, according to the Intergovernmental Panel on Climate Change (IPCC) Sixth Assessment Report (AR6).

In the 21^st century, atmospheric concentrations of SF₆ have risen sharply along with global electric power demand. This heightened demand for electric power is particularly pronounced in China, which has dominated the expansion of the global power industry in the past decade.

A study by researchers at the MIT Joint Program on the Science and Policy of Global Change, Fudan University, Peking University, University of Bristol, and Meteorological Observation Center of China Meteorological Administration has now determined total SF₆ emissions in China over 2011–2021 from atmospheric observations collected from nine stations within a Chinese network, including one station from the Advanced Global Atmospheric Gases Experiment (AGAGE) network.

For comparison, global total emissions were determined from five globally distributed, relatively unpolluted “background” AGAGE stations, involving additional researchers from the Scripps Institution of Oceanography and CSIRO (Australia). The open-access study appears in the journal Nature Communications.

The researchers found that SF₆ emissions in China almost doubled from 2.6 Gigagrams (Gg) per year in 2011 when they accounted for 34% of global SF₆ emissions, to 5.1 Gg per year in 2021, when they accounted for 57% of global total SF₆ emissions. This increase from China over the ten-year period—some of it emerging from the country’s less-populated western regions—was larger than the global total SF₆ emissions rise, highlighting the importance of lowering SF₆ emissions from China in the future.

a) The top–down SF₆ emissions in China derived by nine sites in China in this study were compared to the top–down global SF₆ emissions derived by recent global AGAGE background observations and an atmospheric box model. b) The increase in SF₆ emissions from China between 2011-2013 and 2019-2021 was compared to the corresponding global total increase. An et al.

Emissions of SF₆ are expected to last more than 1000 years in the atmosphere, raising the stakes for policymakers in China and around the world.

Any increase in SF₆ emissions this century will effectively alter our planet’s radiative budget—the balance between incoming energy from the sun and outgoing energy from the Earth—far beyond the multi-decadal timeframe of current climate policies. So it’s imperative that China and all other nations take immediate action to reduce, and ultimately, eliminate, their SF₆ emissions.

—MIT Joint Program and CGCS Director Ronald Prinn, coauthor

The study was supported by the National Key Research and Development Program of China and Shanghai B&R Joint Laboratory Project, the National Aeronautics and Space Administration, and other funding agencies.

Resources

• An, M., Prinn, R.G., Western, L.M. et al. (2024) “Sustained growth of sulfur hexafluoride emissions in China inferred from atmospheric observations.” Nat Commun doi: 10.1038/s41467-024-46084-3