Now that the dust has settled from the climate change conference in Copenhagen last December, it's a good time to step back and take stock. Policymakers and the public had high expectations for the summit and its conclusion left many confused and disappointed. But while the meeting did not reach consensus among all 192 countries required to formally adopt a climate pact, it produced a political agreement called the "Copenhagen Accord," which left it to individual countries to choose whether or not they wanted to sign up.
The results are in and offer hope that the bottom-up approach the accord adopts can move the world in the right direction.
The Copenhagen Accord calls for global emissions to peak as soon as possible and for the world to prevent the rise in global temperatures from exceeding 2 degrees Celsius. But the national actions required to turn that goal into a reality were not defined at the conference. Instead the accord provided appendices for both developed and developing countries to list the emission reductions they plan to make.
On February 1, the United Nations posted a list of countries that have signed up to the Copenhagen Accord along with a catalogue of their emission reduction commitments. As of Thursday, February 4, the list includes 92 countries (40 developed and 52 developing), accounting for 83 percent of global emissions and 75 percent of global population. Of these countries, 64 listed specific national emission reduction plans.
How far do the current pledges get us?
To evaluate the environmental impact of the listed national actions, I measured them against what is projected to occur under business as usual (BAU).1 The BAU trajectory chosen for this analysis captures all national policy enacted through mid-year 2009 but excludes policy only under consideration. It results in growth of global greenhouse gas (GHG) emissions from 45 billion tons in 2005 to 56 billion tons in 2020 to 113 billion tons by 2100. By the end of the century atmospheric GHG concentrations reach 1,055 parts per million (ppm) and global temperatures rise more than 4 degrees Celsius.2
Against this BAU trajectory, the national pledges currently listed in the Copenhagen Accord would reduce emissions to between 49.7 and 51.5 billion tons in 2020 (table 1 and figure 1). That's 7 to 11 percent below BAU. If the $100 billion in international financial assistance called for in the Copenhagen Accord materializes and half is used for emission reductions (the other half helping countries adapt to climate change), it could reduce emissions to as low as 48 billion tons (or 13 percent below BAU).3
|Table 1 The impact of Copenhagen Accord pledges|
|Billion tons CO2e, including land-use change||Emissions||Reduction from BAU|
|Potential mitigation from international finance||0.00||–1.53||0.00||1.53|
|* For Russia and India, the pledges listed in the Accord do not result in a reduction below the business-as-ususal pathway used for this analysis.|
Here some caveats are required. While developed country targets are defined as absolute reductions below a base year, developing country targets are somewhat more relaxed in that they are defined either as a reduction in the amount of CO2 emitted for each unit of economic growth (China and India) or as a reduction below BAU (everyone else). These standards allow developing countries more latitude to achieve the economic growth they need to lift their populations out of poverty.
The actual impact of a specific carbon-intensity target for developing countries, however, depends on how fast their economies grow—faster-than-expected growth will lead to higher emissions. And the impact of a BAU target depends on what the country in question thinks will happen in the absence of policy action. As no country other than Brazil has specified a BAU pathway to date, there is some uncertainty about the emission reductions their targets will ultimately deliver. Finally, achieving the full 1.53 billion tons of mitigation possible through international financial assistance would require that none of those emission reductions get counted against developed country targets (as occurs with international offsets) and none of the major developing countries use international financial assistance to meet the targets inscribed in the Copenhagen Accord. Neither is likely to be entirely the case.
Are the Copenhagen commitments consistent with a 2-degree world?
The Copenhagen Accord only contains emission reduction commitments through 2020. Whether we limit global temperature increases to 2 degrees Celsius also depends on what countries do after 2020. Recent analysis has called for global emissions to peak by 2020 at between 40 and 48 billion tons to have a reasonable chance of meeting a 2-degree long-term temperature goal. That's based on an assessment of what kind of emission reductions post-2020 will be technically and politically feasible. Higher emissions in 2020 will require steeper and more costly reductions thereafter.
Accurately assessing mitigation potential and cost post-2020 requires comprehensive analysis of economic growth trajectories, technological change, and natural resource profiles country-by-country. In the coming months, energy and climate modelers will be doing just that, and providing us with a clearer sense of where the Copenhagen Accord commitments leave the world in 2020.
For the time being, I've used a back-of-the envelope approach to ballpark whether meeting the 2-degree target is possible given the commitments in the Copenhagen Accord by imposing the following two constraints on post-2020 action:
- Equity: No country should be required to make cuts that result in lower per-capita emissions than the European Union in 2050 (including emissions from land-use change), assuming the European Union reduces emissions 80 percent below 1990 levels by 2050.4
- Cost and feasibility: No country should be required to reduce fossil fuel emissions between 2020 and 2050 at a greater annual rate (adjusted for economic growth) than the United States under the American Clean Energy and Security act of 2009 (83 percent below 2005 levels by 2050).5
I modeled these post-2020 emissions pathways, along with the 2005-2020 actions listed in the Copenhagen Accord using the C-ROADS modeling platform developed by Climate Interactive, the Sustainability Institute, and MIT6. The result was a peak in atmospheric GHG concentrations between 487 and 490 ppm (figure 2). Translating that into temperature change is challenging because of uncertainty about the behavior of the climate system. The C-ROADS model shows a likely temperature increase in the 1.3 to 2.4 degrees Celsius range with a "best guess" of 1.8 degrees. This is lower than estimates from the Intergovernmental Panel on Climate Change (IPCC) whose "best guess" on the impact of a 450 to 500 ppm world is between 2.1 and 2.4 degrees Celsius.7 Either way, if countries follow through on their pledges and follow on with more aggressive action, it looks like keeping global temperature increases below 2 degrees Celsius is still within reach. Of course, the more countries ratchet up mid-term action, the better the chances get.
Where do we go from here?
The Copenhagen Accord calls for a review of national actions by 2015 to see if they are indeed putting the world on the right path. Yet given the chaos of the Copenhagen conference, and the fact that the 192 Parties to the UN Framework Convention on Climate Change did not formally adopt the Copenhagen Accord, it's still unclear how the international community puts such a review into action. That's just one of the questions to be addressed as the world thinks through the right way to tackle the climate challenge going forward, something my colleagues and I at the Peterson Institute will be focusing on in the months ahead.
Trevor Houser, visiting fellow at the Peterson Institute for International Economics, served as senior advisor to the US Special Envoy on Climate Change in 2009.
1. The BAU scenario used in this analysis takes emission growth rates projected by the International Energy Agency's 2009 World Energy Outlook from 2005–30. From 2030–2100, emission growth rates are based on an average of the 11 models included in Stanford University Energy Modeling Forum exercise (EMF-22). This results in an emissions pathway in the middle of the range of projections used by the Intergovernmental Panel on Climate Change.
3. Mitigation potential through international financial assistance calculated using the international allowance price in 2020 forecast by the Energy Information Administration under the American Clean Energy and Security Act of 2009.
4. From 2050–2100 all countries' per-capita emissions converge at 1 ton.
5. For Brazil and Indonesia a significant reduction in deforestation is required to achieve per-capita equity with the European Union in 2050.
6. GDP and population growth in my analysis differ from the C-ROADS defaults. GDP growth estimates are from the International Energy Agencies' 2009 World Energy Outlook for 2005–20, and from the 11 models included in Stanford's Energy Modeling Forum for 2020–2100. Population growth estimates are from the UN Population Division for 2005–50 and from EMF-22 for 2050–2100.