A new study in the journal Environmental Research Letters assesses the potential impacts of cumulative emissions from existing fossil fuel plants built in the past few years (2010-2012). During this period, an average of 89 gigawatts of new coal generating capacity was added annually, with natural gas trends soaring at a similar pace during this time. The study by Steven J. Davis and Robert H. Socolow, sought to quantify what they characterized as “an important component of socio-economic inertia,” which they denominated “committed emissions,” or the projected emissions from existing fossil fuel-burning infrastructure globally. The study assumes a 40-year lifetime for fossil-fuel infrastructure built during the period studied.
Their results are both startling and discouraging, emphasizing the incredibly imposing path ahead to decarbonize the world economy and avoid passing critical climatic thresholds. This would be an excellent student reading to also discuss the implications of “committed” emissions in terms of potential policy responses, e.g. carbon capture and sequestration and climate geoengineering.
Among the findings in the study:

1. Despite global efforts to arrest carbon dioxide emissions, total remaining commitments of carbon dioxide emissions from fossil fuel facilities built between 2010-2012 have been growing at a rapid clip of 4% annually;
2. China’s power plant infrastructure represents 42% (129 Gt CO2) of the total remaining commitments from such facilities, with India, the EU and the US responsible for between 23-34 GtCO2 each. The rest of the world is estimated to contribute 31% of the global total in 2012;
3. Of the 307 Gt CO2 of remaining committed emissions as of 2012, a whopping 67% are associated with coal-fired generators; the contribution of natural gas facilities, however, already increased nearly 500% between 1980 and 2012;
4. While the “New Policies” scenario in the IEA’s World Energy Outlook 2013 report projected new global commitments of approximately 5 GtC2yr-1 from coal generators, and 3 Gt CO2yr-1, the study revealed that new commitments from the natural gas sector are roughly double those incorporated into the IEA scenarios. By comparison, the “450[ppm atmospheric concentrations] scenario” of the IEA would necessitate actual reductions in coal-fired generators by early retirement or CCS retrofitting;
5. Assuming a 40-year lifetime for fossil fuel power plants built between 2010-2012, their total emissions bill amount to 19 gigatons of carbon dioxide, compared to 14 gigatons emitted by all fossil fuel power plants in 2012.

Some of the class discussion questions that this study could generate include the following:

• The potential range of emissions commitments is very wide (192-439 GtCO2, or 40%) given high levels of uncertainty about how long such plants may operate in the future. How should policymakers respond to such high levels of uncertainty?;
• What are the best ways to “bend the curve” of committed emissions from a technological and/or political perspective? Is this realistic?
• What the equity implications of committed emissions over the past few years in terms of negotiating a long-term commitment to emissions reductions?