Atmospheric Emissions of Halocarbons and Greenhouse Gases

The atmospheric burden of halocarbons and other fluorinated greenhouse gases has risen steadily since the mid-20th century, driven by industrial production, refrigeration, electronics manufacture and electrical applications. These compounds, which include chlorofluorocarbons (CFCs), hydrochlorofluorocarbons (HCFCs), hydrofluorocarbons (HFCs), perfluorocarbons (PFCs) and sulfur hexafluoride (SF6), are characterised by long atmospheric lifetimes and high global warming potentials. Their radiative forcing contributes measurably to global climate change, while certain species also deplete stratospheric ozone. Efforts under international agreements have led to phased controls and replacements, yet unanticipated emissions from legacy equipment, industrial leaks and rapidly growing economies have offset some gains. Contemporary research combines global monitoring networks with inverse modelling to quantify emission magnitudes, evaluate bottom-up inventories and project future trends under alternative policy scenarios. The global distribution of these gases and their evolving radiative impacts underscore the urgency of strengthened measurement, reporting and mitigation strategies to complement carbon dioxide reductions and safeguard both the climate and the ozone layer.

Research from Nature Portfolio

Recent studies have employed long-term atmospheric observations to reveal surging SF6 emissions from a leading emitter, documenting more than a doubling of national emissions over the past decade and demonstrating that such increases have partially offset reductions in other regions. Parallel work has shown that global radiative forcing and effective chlorine loading from HCFCs have begun to decline earlier than previously projected, providing clear evidence of the benefits of phased production controls for both climate mitigation and ozone recovery. Building on these insights, comprehensive inventories of fluorinated gases have been developed for one of the world’s largest manufacturing economies, revealing accelerating growth in total emissions of high-global-warming-potential species since 1990 and projecting that, without additional regulation, these emissions could more than double by mid-century.

Atmospheric Emissions of Halocarbons and Greenhouse Gases publication trend

The graph below shows the total number of articles in atmospheric emissions of halocarbons and greenhouse gases across all publications each year (not limited to Nature Index journals).

Technical terms

Halocarbon: A family of organic compounds containing carbon bonded to halogen elements, many of which are long-lived greenhouse gases and ozone-depleting substances.

Radiative forcing: The change in energy flux in the atmosphere caused by greenhouse gas accumulation, expressed in watts per square metre.

Global warming potential (GWP): An index comparing the integrated radiative forcing of a unit mass of a greenhouse gas to that of carbon dioxide over a specified time horizon.

Inverse modelling (top-down method): A technique that uses atmospheric concentration measurements and transport models to infer spatial and temporal patterns of emissions.

Atmospheric bank: Reservoirs of halocarbon stored in equipment or products, with potential for delayed release into the atmosphere.

References

1. Sustained growth of sulfur hexafluoride emissions in China inferred from atmospheric observations. Nature Communications (2024).
2. A decrease in radiative forcing and equivalent effective chlorine from hydrochlorofluorocarbons. Nature Climate Change (2024).
3. Substantial increase in perfluorocarbons CF4 (PFC-14) and C2F6 (PFC-116) emissions in China. Proceedings of the National Academy of Sciences of the United States of America (2024).
4. Projected increases in emissions of high global warming potential fluorinated gases in China. Communications Earth & Environment (2023).
5. History of atmospheric SF6 from 1973 to 2008. Atmospheric Chemistry and Physics (2010).
6. Future atmospheric abundances and climate forcings from scenarios of global and regional hydrofluorocarbon (HFC) emissions. Atmospheric Environment (2015).