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Thursday, September 30, 2010

Joeri Rogelj et al., ERL 5 (2010), Analysis of the Copenhagen Accord pledges and its global climatic impacts—a snapshot of dissonant ambitions

Environmental Research Letters5 (July-September 2010) 034013; doi: 10.1088/1748-9326/5/3/034013

Analysis of the Copenhagen Accord pledges and its global climatic impacts—a snapshot of dissonant ambitions

Joeri Rogelj1,2,*, Claudine Chen1, Julia Nabel1,3, Kirsten Macey4, William Hare1,4, Michiel Schaeffer4,5, Kathleen Markmann1, Niklas Höhne6, Katrine Krogh Andersen7 and Malte Meinshausen1

1 PRIMAP Group, Earth System Analysis, Potsdam Institute for Climate Impact Research (PIK), PO Box 60 12 03, 14412 Potsdam, Germany
2 Institute for Atmospheric and Climate Science, ETH Zurich, Universitätstrasse 16, 8092 Zürich, Switzerland
3 Land Use Dynamics, Swiss Federal Institute for Forest, Snow and Landscape Research, Zürcherstrasse 111, 8903 Birmensdorf, Switzerland
4 Climate Analytics GmbH, Telegrafenberg A26, 14473 Potsdam, Germany
5 Environmental Systems Analysis Group, Wageningen University & Research Centre (WUR), PO Box 47, 6700 AA Wageningen, The Netherlands
6 Ecofys GmbH, Am Wassermann 36, 50829 Cologne, Germany
7 Danish Climate Centre, Danish Meteorological Institute, Lyngbyvej 100, 2100 Copenhagen, Denmark


This analysis of the Copenhagen Accord evaluates emission reduction pledges by individual countries against the Accord's climate-related objectives. Probabilistic estimates of the climatic consequences for a set of resulting multi-gas scenarios over the 21st century are calculated with a reduced complexity climate model, yielding global temperature increase and atmospheric CO2 and CO2-equivalent concentrations. Provisions for banked surplus emission allowances and credits from land use, land-use change and forestry are assessed and are shown to have the potential to lead to significant deterioration of the ambition levels implied by the pledges in 2020. This analysis demonstrates that the Copenhagen Accord and the pledges made under it represent a set of dissonant ambitions. The ambition level of the current pledges for 2020 and the lack of commonly agreed goals for 2050 place in peril the Accord's own ambition: to limit global warming to below 2 °C, and even more so for 1.5 °C, which is referenced in the Accord in association with potentially strengthening the long-term temperature goal in 2015. Due to the limited level of ambition by 2020, the ability to limit emissions afterwards to pathways consistent with either the 2 or 1.5 °C goal is likely to become less feasible.

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