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The effect of updated pledges and business-as-usual projections, and new agreed rules on expected global greenhouse gas emissions in 2020

Article | 04-11-2013

Since the climate negotiations in Copenhagen (2009), many countries have pledged to reduce their greenhouse gas emissions by 2020. These pledges were 'anchored' in the 2010 Cancún Agreements. Since the Cancún climate negotiations, developing countries have published new information about their business-as-usual emission projections . These – upward – projections have led to higher expected emission levels from the pledges, and have increased the emission gap towards achieving the 2 degree Celsius (C) climate goal.

The Copenhagen Accord of 2009 refers to a 2°C target and encouraged countries to submit emission reduction proposals and actions (pledges) for the year 2020, which many did. Several studies determined the effect of these pledges on the global emission level in 2020, and analysed the gap between this emission level and the level consistent with least-cost emission pathways for achieving the 2° C target. These studies were summarised in the UNEP emission gap reports.

Since the UNFCCC climate negotiations in Cancún, 2010, business-as-usual emission projections have been updated and some countries submitted new pledges or clarified existing pledges. Furthermore, new accounting rules for land use and the use of surplus units were agreed in Durban (2011) and Doha (2012).

This paper shows that together, these developments have led to an increase in the emission level resulting from the pledges of about 4 Gigaton (Gt) CO2 equivalent. compared to our assessment before Cancún, mainly due to increased business-as-usual projections. According to our projections, the pledges lead to an emission level of 52.7-56.5 Gt CO2 equivalent by 2020, which implies an emission gap of 8.7 - 12.6 Gt CO2 equivalent for a likely chance (greater than 66% likelihood) and from 6.7 to 10.6 Gt CO2 equivalent. for a medium chance (50-66% likelihood) of achieving 2° C. This does not imply that achieving 2° C is out of reach with the current pledges, but it will require higher reduction rates beyond 2020 and will depend more heavily on future technological developments.

Author(s)Andries F. Hof; Michel G.J. den Elzen; Mark Roelfsema
Publication date04-11-2013
PublicationEnvironmental Science and Policy
ReferenceVolume 33, 2013, Pages 308-319