28 May 2009: The Intergovernmental Panel on Climate Change (IPCC) Secretariat has released the extended report of the expert meeting on the Science of Alternative Metrics, which took place in Oslo, Norway, from 18-20 March 2009. The report has also been forwarded to the UNFCCC.

The expert meeting was conducted in response to an invitation from the UNFCCC Ad Hoc Working Group on Further Commitments for Annex I Parties under Kyoto Protocol (AWG-KP) to the IPCC to undertake further technical assessment of alternative common metrics that are used to calculate the carbon dioxide equivalence of anthropogenic emissions by sources, and removals by sinks, of greenhouse gases listed in Annex A to the Kyoto Protocol. The event gathered 35 participants from around the world, including 21 leading experts in the area of greenhouse gas metrics. Among other outcomes, meeting participants unanimously agreed that: Global Warming Potential (GWP) is a useful and well defined metric; effectiveness of the use of a given metric depends on the primary policy goal; numerical value of the GWP can depend markedly on the choice of time horizon; and timely information on future policy goals would facilitate research on alternative metrics. [The Report]