Global warming potentials

All greenhouse gases (GHGs) are not equal. Each one has a unique atmospheric lifetime and heat-trapping potential.

The Global Warming Potential (GWP) metric examines each greenhouse gas’s ability to trap heat in the atmosphere compared to carbon dioxide (CO₂). We measure this over a specified time horizon. Often, we calculate GHG emissions in terms of how much CO₂ is essential to produce a similar warming effect over the chosen time horizon. This is the carbon dioxide equivalent (CO₂ eq) value. We calculate it by multiplying the amount of gas by its accompanying global warming potential (GWP).

The Intergovernmental Panel on Climate Change (IPCC) provided 100-year GWPs in its Fourth Assessment Report (SAR). These GWPs are consistent with Decision 24/CP.19. They are required for inventory reporting under the United Nations Framework Convention on Climate Change (UNFCCC). They are also required for facility GHG reporting under Section 46 (S.46) of the Canadian Environmental Protection Act.

Global warming potentials for greenhouse gases

Note: '-' indicates that a GWP for this GHG was not available in the IPCC Second Assessment Report.

^a Data source: IPCC’s Summary for Policymakers and Technical Summary of the Working Group I Report (IPCC 1995).

^b Data source: IPCC's Fourth Assessment Report - Errata (IPCC 2012).

Note: '-' indicates that a GWP for this GHG was not available in the IPCC Second Assessment Report.

^a Data source: IPCC’s Summary for Policymakers and Technical Summary of the Working Group I Report (IPCC 1995).

^b Data source: IPCC's Fourth Assessment Report - Errata (IPCC 2012).

Note: '-' indicates that a GWP for this GHG was not available in the IPCC Second Assessment Report.

^a Data source: IPCC’s Summary for Policymakers and Technical Summary of the Working Group I Report (IPCC 1995).

^b Data source: IPCC's Fourth Assessment Report - Errata (IPCC 2012).