Implications of Near-term Climate Actions for Long-term Outcomes

An important new research direction was to focus on the interplay between near-term policies and the feasibility of meeting long-term climate objectives. This involved an in-depth evaluation of current international climate agreements, such as the Copenhagen Accord and Cancún Agreements.

Within the framework of the EU Framework Programme (FP) 7 AMPERE project, ENE led a multi-model comparison effort involving more than ten international teams from Asia, the United States, and Europe to evaluate the impact of near-term climate policies. More than 300 scenarios were developed in 2012, and results of this major collaborative effort will appear as a special issue in the journal Technological Forecasting and Social Change, with ENE Program Leader Keywan Riahi serving as the Managing Guest-Editor.

In the overview paper of the issue, ENE researchers Keywan Riahi, Nils Johnson, Volker Krey, and David McCollum summarize the findings of the multi-model comparison and explain that higher-than-optimal greenhouse gas emissions resulting from current climate agreements up to 2030 must be compensated for by much deeper emissions reductions in the medium and long term, if targets like the 2ºC are to be achieved later in the century (see Figure below).  

Development of greenhouse gas emissions. Current weak climate policies shift deep reductions to later in time, and imply higher risks that low stabilization targets are getting out of reach.

Of particular concern is the rate of energy system transformation required between 2030 and 2050 and the eventual reliance on substantial negative emissions to reach the target. As a result, less aggressive actions in the near term would lead to greater reliance on technologies that can achieve negative emissions (e.g., bioenergy with carbon capture and storage [CCS]), to greater risk that stringent long-term targets (e.g., 2ºC warming) will not be attainable, and to larger mitigation costs over the full century.

ENE researchers Joeri Rogelj, David McCollum, and Keywan Riahi conducted a more detailed analysis of this issue in a paper published in the prestigious journal Nature Climate Change (December 2012), which describes how different GHG emissions levels in 2020 would impact the feasibility of achieving the 2ºC target in the long term, given various scenarios regarding energy efficiency and technology improvements, technology availability, and regional participation in mitigation efforts. The major contribution of this paper is the identification of “feasibility windows” that indicate the range of global GHG emissions in 2020 that would provide a high probability of achieving the long-term target in each scenario. The paper identifies critical 2020 GHG emissions thresholds for meeting the long-term target by hedging against the risks of potential technological failures and the uncertainty of sociopolitical developments.

ENE’s work in this area provides valuable findings that have important implications for future international climate negotiations and the Durban Action Plan, which seeks to establish effective post-2015 GHG emissions targets. For instance, both of the above papers identify similar measures that are particularly critical in maintaining a wide feasibility window, including energy efficiency improvements and the availability of CCS and land-based mitigation measures. 

Last edited: 30 October 2013