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000590 IN DEPTH CLIMATE CHANGE Life After Kyoto? Exploration of Lo.ng- Term Climate Policy Strategies Detlef van Vuuren Editor s note: An earlier version of this report was published in 55 Change, the research and policy news letter on Global Change from the Netherlands. The overarching objective of the United Nations Framework Convention on Climate Change (UNFCCC) is to achieve "stabilization of greenhouse gas concentra- tions in the atmosphere at a level that would prevent dan- gerous anthropogenic interference with the climate sys- tem" (Article 2). This requires long-term strategies to stabilize emissions. At the 6th Conference of the Parties to the UNFCCC , the Netherlands National Institute for Health and Envi- ronment organized a side event with the title "Life after Kyoto: Exploring long term strategies to control climate change" to discuss the contours of a plan that looks be- yond the next decade. What Greenhouse Gas Levels are "Safe"? At the outset of the meeting, Rik Leemans made a presentation that focused on the quantification of climate policy objectives. He began with a proj ection of temperature increases over the next century in the absence of mitigation poli- cies, based on baseline scenarios taken from the "Special Report on Emission Scenarios," recently issued by the Intergovernmental Panel on Climate Change. These scenarios yield a temperature change of between 1.5 and 60C and sea level rise of between 50-80 centimetres by 2100. This will undoubtedly bring about substantial changes in climate. In some cases, the impacts may be positive (such as extra precipitation in certain arid areas, for instance), while in many other cases the impacts will be disad- vantageous. Recent research has demonstrated that in the case of Detlef van Vuuren is a researcher with the Climate Change Team of the Department of Environment & Nature Assessment, National Institute of Public Health and the Environment, The Netherlands larger temperature increases, .the balance will shift from both positive and negative impacts to a situation in which the disadvantages clearly outweigh the benefits. If the objec- tive ofthe UNFCCC is also to limit the worst climate consequences at the regional level, and to protect cer- tain unique ecosystems, then current research increasingly indicates that we must limit temperature increases to no more than 20C above the level at the start of the 20th century. What this means in terms of the level at which atmo- spheric greenhouse gases must be stabilized is strongly dependent on the sensitivity of climate to increases in such levels. If the climate has low sensitivity (I.50C after a dou- bling of greenhouse gas concentrations), then the carbon dioxide concentration will have to be stabilized below 650 ppmv to stay within the 20C increase. If the climate is highly sensitive (4.50C after doubling), the stabilization target can only be achieved at levels below 350 ppmv. (Editor s note: A new study by researchers at the University of Illinois, released in June, indicates that the Earth s climate system is likely to be highly sensi- tive over the next century to increases in greenhouse gases, perhaps outstripping even the upper bound- aries projected by the IPCC.) However, given the fact that it is probably politically impossible to stabilize emissions at 350ppmv or below by the end of the century, the focus is now on how to stabi- lize emissions at 45Oppmv. Is Stabilization Possible? In his presentation, Bert de Vries emphasized that cli- mate policy scenarios are integrally tied to development strategies and priorities. For example, will material growth be important, or will immaterial matters, such as healthcare and the environ- ment, receive greater attention? Continued on next page