The latest report by the International Panel on Climate Change (IPCC) – the UN body that assesses the science related to climate change – emphasizes the critical role of low-GWP refrigerants, such as CO2 (R744), in the rapid phase down of HFCs under the Kigali Amendment.

The report, “Climate Change 2022: Mitigation of Climate Change,” was published on April 4, and encompasses the “Working Group III contribution to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change.”

If the Kigali Amendment is ratified by all 198 signatories, “the rapid phase-down of HFCs … [will be] possible because of extensive replacement of high-global warming potential (GWP) HFCs with commercially available low-GWP alternatives in refrigeration and air-conditioning equipment,” the IPCC report says. At present, 130 of the 198 parties to the Montreal Protocol have ratified the Kigali Amendment.

Each country’s choice of alternative refrigerants will likely be determined by energy efficiency, costs, and refrigerant toxicity and flammability, the report notes, adding, “National and regional regulations will be needed to drive technological innovation and development.” For example, China and India have developed detailed cooling action plans that lay out their HFC phase-down plans, and many other countries have included action on HFCs in their Nationally Determined Contributions toward the Paris Climate Accord.

The Article 6 mechanisms under the Paris Accords “could generate financial incentives for HFC mitigation and related energy efficiency improvements,” the IPCC report says. Moreover, early action under Article 6 “could drive down baseline levels of HFCs for developing countries,” which will be based on production and consumption in the early and mid-2020s. This in turn would generate long-term mitigation benefits under the Kigali 8 Amendment, the report adds.

However, achievement of the objectives of the Kigali Amendment is dependent on its ratification by key developed countries, such as the U.S., and the provision of funds by developed countries through the Montreal Protocol’s Multilateral Fund to meet developing countries’ agreed incremental costs of implementation, the report says.

Recently, two U.S. Senators – John Kennedy of Louisiana and Tom Carper of Delaware – urged the Senate Foreign Relations Committee to send the Kigali Amendment to the full Senate for ratification.

Impact of Kigali

The Kigali Amendment and related national and regional regulations are projected to reduce future radiative forcing from HFCs by about half in 2050 compared to a scenario without any HFC controls, the report says. In addition, the amendment is expected to reduce future global average warming in 2100 from a baseline of 0.3–0.5°C (0.5–0.9°F) to less than 0.1°C (0.2°F), according to a 2018 scientific assessment of the literature by the World Meteorological Organization, cited by the report.

Due to their use in cooling equipment like air conditioners, HFCs are considered the fastest-growing greenhouse gas in the world. According to the United Nations Environment Programme, HFC emissions could account for 7-19% of global CO2e emissions by 2050 without a phase down of the gases.

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