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 18/CMA.1 They are required for inventory reporting under the United Nations Framework Convention on Climate Change (UNFCCC). GWPs are also required to be used for facility GHG reporting under Section 46 (S.46) of the Canadian Environmental Protection Act.  The updated values from the IPCC’s Fifth Assessment report will apply to facility GHG reporting, starting with reporting for the calendar year 2022.

Global warming potentials for greenhouse gases

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

^b Data source: IPCC, 2013: Climate Change 2013: The Physical Science Basis. Contribution of Working Group I to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change [Stocker, T.F., D. Qin, G.-K. Plattner, M. Tignor, S.K. Allen, J. Boschung, A. Nauels, Y. Xia, V. Bex and P.M. Midgley (eds.)]. Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA, 1535 pp.  

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

^b Data source: IPCC, 2013: Climate Change 2013: The Physical Science Basis. Contribution of Working Group I to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change [Stocker, T.F., D. Qin, G.-K. Plattner, M. Tignor, S.K. Allen, J. Boschung, A. Nauels, Y. Xia, V. Bex and P.M. Midgley (eds.)]. Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA, 1535 pp.  

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

^b Data source: IPCC, 2013: Climate Change 2013: The Physical Science Basis. Contribution of Working Group I to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change [Stocker, T.F., D. Qin, G.-K. Plattner, M. Tignor, S.K. Allen, J. Boschung, A. Nauels, Y. Xia, V. Bex and P.M. Midgley (eds.)]. Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA, 1535 pp.