Global Warming Potential (GWP)

Definition

Global Warming Potential, commonly abbreviated as GWP, is a measure used to compare the climate impact of different greenhouse gases.

GWP compares how much heat a given mass of a greenhouse gas traps in the atmosphere relative to the same mass of carbon dioxide over a specified time period.

Carbon dioxide is used as the reference gas and has a GWP of 1.

A gas with a higher GWP has a greater warming effect per unit of mass than carbon dioxide over the same time horizon.

Context

Different greenhouse gases behave differently in the atmosphere.

Some absorb more infrared radiation than others, while some remain in the atmosphere for much longer periods. GWP combines these effects into a single comparison metric.

The metric is widely used in greenhouse gas inventories, environmental regulation, emissions reporting, and refrigerant selection.

For cooling systems, GWP is particularly relevant because refrigerants can escape into the atmosphere through leakage, servicing, accidental release, or equipment disposal.

Refrigerants with lower GWP values can therefore reduce the potential climate impact associated with refrigerant emissions.

Technical insight

GWP is based primarily on two characteristics of a greenhouse gas:

• How effectively the gas absorbs energy in the atmosphere
• How long the gas remains in the atmosphere

These characteristics are compared with carbon dioxide over a defined time horizon.

GWP100

The most commonly used metric is GWP100, which evaluates warming impact over 100 years.

For example, if a gas has a GWP100 of 1,000, one kilogram of that gas has approximately the same integrated warming impact over the specified period as 1,000 kilograms of carbon dioxide.

Using a common time horizon makes it possible to compare different greenhouse gases and express their emissions as carbon dioxide equivalents.

Carbon dioxide equivalent

GWP can be used to convert emissions of different greenhouse gases into carbon dioxide equivalent, commonly written as CO₂e.

For example, if 1 kg of a refrigerant with a GWP of 600 is released, its direct greenhouse gas impact can be expressed as approximately 600 kg CO₂e.

This makes it possible to compare emissions from gases with very different atmospheric properties using a common unit.

Why GWP values can differ

A refrigerant does not necessarily have one permanent GWP value.

Scientific understanding of atmospheric lifetimes, radiative effects, and climate interactions develops over time. The Intergovernmental Panel on Climate Change therefore updates GWP estimates between assessment reports.

Different regulations and technical documents may also reference different IPCC assessment methodologies.

As a result, the same refrigerant may be listed with different GWP values depending on the reference methodology being used.

When comparing refrigerants, GWP values should therefore be taken from the same assessment framework.

GWP and refrigerants

Global warming potential has become an important factor in refrigerant selection.

Many traditional HFC refrigerants have comparatively high GWP values, while newer refrigerants and refrigerant blends can provide significantly lower values.

Lower-GWP options include HFO refrigerants, HFO/HFC blends, carbon dioxide, hydrocarbons, ammonia, and other refrigerants selected for lower climate impact.

However, GWP is only one factor in refrigerant selection.

Cooling capacity, energy efficiency, operating pressure, toxicity, flammability, equipment compatibility, and regulatory requirements must also be considered.

Direct and indirect climate impact

GWP describes the direct climate impact of a greenhouse gas released into the atmosphere.

It does not by itself describe the complete environmental impact of a cooling system.

A cooling system can also create indirect greenhouse gas emissions through the electricity required to operate compressors, fans, pumps, and other components.

For this reason, evaluating cooling system sustainability requires consideration of both refrigerant emissions and energy consumption.

A refrigerant with a very low GWP does not automatically make a cooling system environmentally optimal if the system operates inefficiently.

Key advantages of GWP as a metric

• Enables comparison between different greenhouse gases
• Provides a common basis for emissions reporting
• Supports calculation of carbon dioxide equivalent emissions
• Helps compare refrigerant climate impacts
• Supports environmental regulation and refrigerant transition
• Provides a standardized framework for greenhouse gas inventories

Applications

GWP is relevant across industries using refrigeration and air-conditioning equipment.

Data center and IT infrastructure

Cooling equipment used in data center and IT infrastructure can be evaluated partly according to the GWP of the refrigerant used alongside cooling performance and energy efficiency.

Telecom and connectivity

Outdoor air conditioners used throughout telecom and connectivity infrastructure can use lower-GWP refrigerants to reduce the potential climate impact associated with refrigerant leakage.

Industrial automation

Cooling equipment supporting industrial automation can incorporate lower-GWP refrigerants as part of broader efforts to reduce environmental impact.

Energy and grid infrastructure

Cooling systems used throughout energy and grid infrastructure can consider refrigerant GWP alongside energy efficiency, reliability, and equipment operating requirements.

Oil, gas and mining

Air-conditioning and refrigeration equipment used in oil, gas and mining applications may be subject to refrigerant requirements influenced by regional environmental regulations.

Defense and security

Cooling equipment supporting defense and security applications can also use GWP as one factor when evaluating refrigerant technologies and environmental performance.

FAQ