Heading into the final stage of international negotiations on a post-Kyoto agreement, it is not yet clear that consensus can be reached. Because global emissions must be reduced sharply to ultimately stabilize the climate, developed countries are calling for the developing countries to join in the commitment to sharply reduce greenhouse gas emissions. Developing countries, on the other hand, presently have much lower per capita emissions and have been rejecting the idea of a cap on their CO2 emissions. Last year, Dr. Michael MacCracken, the Climate Institute’s Chief Scientist for Climate Change Programs, published a paper in the Journal of the Air and Waste Management Association (MacCracken, 2008) suggesting that the deadlock between developed and developing nations might be broken by having the developed nations push hard on emissions reductions of all species in order to demonstrate that a modern society can prosper without having high greenhouse gas emissions, while the developing nations initially focus on improving energy efficiency and making sharp reductions in short-lived species, especially methane, soot, and the pollutants that contribute to build-up of tropospheric ozone, and only later join in actually reducing their CO2 emissions.
In Dr. MacCracken’s 2008 publication, the notion was conceptual. Earlier this year, Ms. Frances Moore (formerly an intern with the Climate Institute and now a graduate student at the Yale School of Forestry and Environmental Studies) and Dr. MacCracken published an article in the International Journal of Climate Change Strategies and Management that sought to make the original proposal more quantitative. Their article (Moore and MacCracken, 2009), entitled “Lifetime-leveraging: An approach to achieving international agreement and effective climate protection using mitigation of short-lived greenhouse gases,” suggested a joint approach with differentiated responsibilities, as called for in the original United National Framework Convention on Climate Change.
Human activities have already increased the concentrations of greenhouse gases in the atmosphere enough to, in the absence of the cooling influence of sulfate aerosols, ultimately raise the global average temperature to roughly 2°C over its preindustrial value. Many natural systems such as the Arctic Sea, Antarctic ice shelves, and the Greenland ice sheet have already begun to deteriorate, with the global average temperature increase to date being only about 0.8°C, suggesting that the impacts to critical resource systems from a 2°C warming could well be unacceptable (or ‘dangerous’) to society.
To stay below the 2°C warming, Moore and MacCracken (2009) indicate that this will require concerted action by both developed and developing nations, which they instead subdivide into high, middle, and low-income nations. For high-income nations, roughly an 80% reduction in all greenhouse gas emissions is required by 2050, followed by further cutbacks over the rest of the century. But, this will not be enough, because, even if the high-income nations can accomplish this, even modest emissions growth scenarios in the middle (nations with GDP between $3000 and $10000 per capita) and low (GDP <$3000 per capita) income nations will cause global emissions, and thus the increase in atmospheric concentrations of greenhouse gases and in global average temperature, to exceed unacceptable levels.
To limit global warming to below about 2°C, the Lifetime Leveraging approach proposes that, in addition to increasing the efficiency of their use of fossil fuels, the middle and low income nations also focus their initial efforts on reducing emissions of the short-lived pollutants (i.e., methane and soot) because of both their importance and the fact that emissions reductions can quickly reduce the atmospheric concentrations of these gases to below current levels. Specifically, middle-income nations would, instead of agreeing to a cap on their CO2 emissions, set sectoral intensity targets for fossil fuel use for multiple energy-intense industrial sectors. In addition, to help offset their increasing in CO2 emissions, they would commit to sharply reducing their emissions of methane (CH4), soot, and the pollutants that contribute to the formation of tropospheric ozone. Requirements for low-income nations would be the least restrictive, requiring them only to pursue targets consistent with their UN-agreed upon Millennium Development Goals, to which they have already agreed and which would promote the health and well-being of their citizens (SEG, 2007). For both middle- and low-income nations, as their per capita GDP rose to the next higher category, they would ‘graduate’ into stricter emission-reduction regimes, so eventually the system would move toward equal obligations and equal per capita emissions.
The Lifetime Leveraging approach assumes that the emissions reductions will be encouraged using either a comprehensive cap and trade system or carbon tax. As is the case under the Kyoto Protocol, it is envisioned that there could be trading of emissions reduction requirements by using the CO2-equivalent emission for each species. To promote even greater attention to reducing emissions of CH4, which exerts a very strong near-term warming influence, Moore and MacCracken (2009) propose that the CO2-equivalence for methane be based on its significantly higher 20-year Global Warming Potential (GWP) rather than its 100-year value.
Because CO2 emission caps are not initially applicable to middle and low-income nations, mechanisms to support clean development will be a useful investment to help these nations improve their energy efficiency. Based on a credit-system, reductions below an agreed-upon baseline would be allowed to be sold to other countries to satisfy their emission reduction goals, or if they wish, these credits could be banked to meet their future reduction requirements. Moore and MacCracken’s proposal also recognizes that technology transfer will be an important process to help countries generate further emissions reductions. They suggest that one way to promote technology transfer would be to have a premium for carbon credits that encourage and enable capacity building and technology transfer in the receiving country—basically, the objective would be to incentivize emissions reductions.
Lifetime Leveraging “recognizes that there are political tradeoffs that will have to be made in negotiating the next climate treaty, and offers a way of approaching these tradeoffs that could minimize resulting environmental damage” (Moore and MacCracken, 2009). There is still the potential for the world to reduce emissions sufficiently to limit the likelihood of the most unacceptable changes in climate, and Lifetime Leveraging offers an approach that the authors hope can break the apparent international negotiating deadlock between developed and developing countries with a logical and equitable solution.
MacCracken, M. C., 2008: Prospects for Future Climate Change and the Reasons for Early Action, Journal of the Air and Waste Management Association 58, 735-786.
Moore, F. C., and M. C. MacCracken, 2009: Lifetime-leveraging: An approach to achieving international agreement and effective climate protection using mitigation of short-lived greenhouse gases, International Journal of Climate Change Strategies and Management 1, 42-62.
Scientific Expert Group on Climate Change (SEG), 2007: Confronting Climate Change: Avoiding the Unmanageable and Managing the Unavoidable, R. M. Bierbaum, J. P. Holdren, M. C. MacCracken, R. H. Moss, and P. H. Raven (eds.), Report prepared for the United Nations Commission on Sustainable Development by Sigma Xi, Research Triangle Park, NC, and the United Nations Foundation, Washington, DC, 144 pp.
Dr. MacCracken, Chief Scientist for Climate Change Programs of the Climate Institute since 2002, has played a crucial role in the development of both scientific and public understanding of implications of climate change. Before joining the Climate Institute, he served as executive director of the National Assessment Coordination Office, which facilitated preparation of the US National Assessment of Climate Change published in 2000. He also played an important role in both the Arctic Climate Impact Assessment published in 2004 (Synthesis Report) and the Special Experts Group report prepared in 2007 under the auspices of Sigma Xi and the UN Foundation for the UN Commission on Sustainable Development, and titled: Confronting Climate Change: Avoiding the Unmanageable and Managing the Unavoidable. From 2003 to 2007 Dr. MacCracken served as President of the International Association of Meteorology and Atmospheric Sciences. In addition, Dr. MacCracken’s Affidavit on behalf of the plaintiffs was cited by Justice Stevens in the Majority Opinion of the United States Supreme Court in Massachusetts v. EPA. Honoring the 20th Anniversary of the founding of the Climate Institute, Dr. MacCracken organized the September 19, 2006 scientific symposium at the Washington Summit on Climate Stabilization and was the lead editor of the resulting book, Sudden and Disruptive Climate Change: Exploring the Real Risks and How We Can Avoid Them.
An update on Lifetime Leveraging: In a paper submitted to appear in the Proceedings of the 42nd Session of the International Seminars on Planetary Emergencies, held August 20-23, 2009 in Erice, Sicily, Italy, Dr. MacCracken further explores the climate effect of focusing on reducing non-CO2 greenhouse gases. Moderating Climate Change by Limiting Emissions of Both Short- and Long-Lived Greenhouse Gases (PDF)
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