Researchers at the Institute for Governance and Sustainable Development (IGSD) in Washington, D.C., have concluded that inaction on short-lived climate pollutants like HFCs risk undermining the efforts to limit global warming.

By looking at models, the researchers found that non-CO2 greenhouse gases (GHG), such as HFCs, are responsible for nearly half of all GHG climate-altering effects. They concluded that the importance of non-CO2 pollutants, particularly short-lived climate pollutants (SLCP), in climate mitigation has been underrepresented.

The article “Mitigating climate disruption in time: A self-consistent approach for avoiding both near-term and long-term global warming” was published in volume 19 of the Proceedings of the National Academy of Science (PNAS).

The aim of the research is to analyze the role of CO2, non-CO2 GHGs and aerosols in near- and long-term climate mitigation strategies, as well as the net effect of policies targeting the phase out of fossil fuels by 2050. The researchers simulated how the planet would react if only direct decarbonization policies were enacted – i.e., replacing fossil fuels with renewables.

Without any action to cut short-lived pollutants, such as fluorinated refrigerants, the planet would warm faster in the near term (up to 2050), limiting the likelihood that we can stay within the 1.5°C (2.7°F) increase limit proposed in the Paris Agreement, according to the article’s authors. “Absent deep cuts in non-CO2 emissions, CO2 abatement alone is unable to keep warming below even the 2°C threshold by 2050,” they explained.

“We have to win the sprint to slow warming in the near term by tackling the short-lived climate pollutants, [such as HFCs], so that we can stay in the race to win the marathon against CO2,” said Gabrielle Dreyfus, chief scientist at the IGSD and lead author of the study in an article following its release.

Long-term vs short-term mitigation

The article underlines that in the long-term, decarbonization efforts would yield the best results as they focus on carbon dioxide, a molecule with a long life in the atmosphere.

“However, a new set of issues has emerged because of the link between warming and extreme weather and the risk of crossing uncertain tipping points that increase additional warming,” the authors point out. “The critical need to curb near-term warming and limit warming to well below 2°C requires broadening the zero carbon dioxide emission approach, which focuses on mitigating the long-term warming, with other approaches that can quickly reduce the near-term warming by including non-CO2 warming pollutants as an additional major focus of climate mitigation action”.

The study points out that the importance of SLCPs like HFCs has been underrepresented in the public debate related to global warming. “Many publications and reports by scientific agencies highlighted the role of non-CO2 for rapid near-term climate mitigation, specifically SLCPs – methane, black carbons, HFC, and tropospheric ozone,” the study recalls, lamenting however that these calls “have not captured the attention of global mitigation actions, which still focuses largely on CO2 emissions.”

The researchers also remark that using shorter time spans to assess the effect of GHGs would better “account for the important differences between strategies that can reduce warming in the near term.” Adopting a 20-year GWP instead of the currently favored 100-year GWP would also see the GWP values of many commonly used HFCs increase drastically, reflecting their short-term global warming effect.

The production and consumption of HFCs has been targeted globally by the Kigali Amendment to the Montreal Protocol since its adoption in 2016. In the European Union the F-gas Regulation is currently being revised, including a proposal to cut the allowed amount of HFCs on the market by 97.27% by 2048. The U.S. is also moving to curb the use of HFCs, having proposed a phase down of 85% by 2036 and discussing further action on the technology transition and refrigerant management.

However, the U.S. ratification of the Kigali Amendment has still not been announced. The American legislation and ongoing debate will be discussed at the ATMOAmerica conference in Washington, D.C., on June 7–8. For more info and to register, click here.

Another global economic heavyweight that is taking action on HFCs is China, which ratified the Kigali Amendment in June 2021. Chinese HFC represented more than half of the imports into the EU-27+UK in both tons and MtCO2e in 2020.

“We have to win the sprint to slow warming in the near term by tackling the short-lived climate pollutants [such as HFCs] so that we can stay in the race to win the marathon against CO2.”

Gabrielle Dreyfus, IGSD

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