Global warming potential (GWP)
Short answer · Updated 2026
Global warming potential (GWP) is an index that compares how much heat a gas traps in the atmosphere with the same mass of carbon dioxide over a set time, normally 100 years. CO2 is 1. Common HFC refrigerants score in the thousands: R-134a is 1,430, R-410A is 2,088 and R-404A is 3,922.
Global warming potential is an index for comparing how strongly different gases warm the planet. It expresses the heat trapping effect of releasing a given mass of a substance relative to releasing the same mass of carbon dioxide over a chosen time horizon. Carbon dioxide is the baseline, and gases that absorb infrared radiation more effectively, or persist longer in the atmosphere, score higher on the index.
Refrigerants are prominent in GWP discussions because many of them are extraordinarily effective heat trappers relative to their mass. A refrigerant charge that escapes from a single system can have a warming effect out of all proportion to its physical quantity. This is the environmental logic that outlived the ozone problem: even refrigerants that are completely ozone safe can still carry a significant climate footprint when released.
For a technician, GWP is the concept behind the industry's current direction of travel. Refrigerant selection increasingly favors lower GWP chemistry, equipment is being designed around new fluids, and the professional habit the number reinforces is the same one Section 608 has always demanded: keep the charge in the system, recover it when the system is opened, and treat every avoided release as the point of the job.
Common questions
What is GWP?
GWP stands for global warming potential: a number that says how strongly a gas warms the planet compared with the same mass of carbon dioxide, which is set at 1. Refrigerant GWPs are normally quoted over a 100-year horizon.
What is the definition of global warming potential?
Global warming potential is the heat-trapping effect of releasing a given mass of a substance, relative to releasing the same mass of CO2, over a chosen time horizon. A higher number means a bigger climate effect per pound released.
What are the GWPs of common refrigerants?
R-134a is 1,430, R-410A is 2,088 and R-404A is 3,922 (100-year values from the IPCC Fourth Assessment Report, as used in EPA's AIM Act rules). Low-GWP HFOs such as R-1234yf are in the single digits.
Why do global warming potentials matter for EPA 608?
Even refrigerants with zero ozone depletion can carry a large climate footprint when vented. That is why the venting prohibition and recovery rules reach HFCs and other substitutes, and why HFC production is being phased down.
Sources
- Global warming potentials: IPCC Fourth Assessment Report, as adopted in EPA's AIM Act regulations (40 CFR Part 84).
- Venting prohibition: 40 CFR 82.154.
Related terms
| HFC (hydrofluorocarbon) | A chlorine free refrigerant family that spares the ozone layer but can strongly trap heat in the atmosphere. |
| Ozone depletion | The destruction of stratospheric ozone by chlorine bearing chemicals, and the original reason refrigerant venting is prohibited. |
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