Stabilization of Atmospheric Greenhouse Gases Physical. Biological and Socur-econome Implications A PORTFOLIO OF ACTIONS ".. that Policy makers could consider to implement low cost and/or cost effective measures (Source: SAR WGIII: Summary for Policymakers.) Implementing energy efficiency measures including the removal of institutional barriers to energy efficiency improve ments; Phasing out existing distortionary policies and practices that increase greenhouse gas emissions, such as some subsidies and regulations, non-internalization of environmental costs, and distortions in transport pricing: Implementing cost-effective fuel switching measures from more to less carbon-intensive fuels and to carbon-free fuels such as renewables; Implementing measures to enhance sinks or reservoirs of greenhouse gases such as improving forest management and land-use practices; Implementing measures and developing new techniques for reducing methane, nitrous oxide and other greenhouse gas emissions; • Encouraging forms of international cooperation to limit greenhouse gas emissions, such as implementing coordinated carbon/energy taxes, activities implemented jointly, and tradeable quotas; Promoting the development and implementation of national and international energy efficiency standards; Planning and implementing measures to adapt to the consequences of climate change; Undertaking research aimed at better understanding the causes and impacts of climate change and facilitating more effective adaptation to it; Conducting technological research aimed at minimizing emissions of greenhouse gases from continued use of fossil fuels and developing commercial non-fossil energy sources; Developing improved institutional mechanisms, such as improved insurance arrangements, to share the risks of damages due to climate change; 39 Promoting education and training, implementing information and advisory measures for sustainable development and consumption patterns that will facilitate climate change mitigation and adaptation. Stabilization of Atmospheric Greenhouse Gases: Physical, Biological and Socio-economic Implications portfolio of actions addressing climate change and adjusting it over time in light of improved information. To implement a portfolio of actions to address climate change, governments must decide both the amount of resources to devote to this issue and the mix of measures they believe will be most effective. With regard to the former, the issue is how far to proceed beyond purely no-regrets options. As noted in SAR WGIII, "the risk of aggregate net damage due to climate change, consideration of risk aversion, and the application of the precautionary principle provide rationales for action beyond no-regrets". The decision on how much action to take depends on the "stakes", the "odds" and the costs of policy measures. The risk premium - the amount that a society is willing to pay to reduce a risk-ultimately is a political decision that differs among countries. Stabilization of Atmospheric Greenhouse Gases: Physical, Biological and Socio-economic Implications backs to increased global temperatures. Climatic Change, 22, trial ecosystem responses to climate change and CO2 doubling. 293-303. Global Biogeochemical Cycles, 9, 407-438. United Nations, 1992: Earth Summit Convention on Climate VEMAP Participants, 1995: Vegetation/Ecosystem modelling and analysis project (VEMAP): Comparing biogeography and biogeochemistry models in a continental-scale study of terres Wigley, TM.L. and S.C.B. Raper, 1992: Implications for climate and sea level of revized IPCC emissions scenarios. Nature, 357, 293-300. Wigley, T. M. L., R. Richels and J. A. Edmonds, 1996: Economic and environmental choices in the stabilization of atmospheric CO2 concentrations. Nature, 379, 242-245. Appendix 1 Temperature and Sea Level Consequences of Stabilization of CO, Concentrations from 1990 to 2300 Section 2.3 discussed the temperature and sea level implications of greenhouse gas stabilization, focusing on the period 1990 to 2100. In order to give a longer term perspective, the temperature and sea level results shown in Figures 11 to 15 (and discussed in Section 2.3) are presented in this Appendix, extended out to 2300 (Figures A1 to A5). Global temperature change (°C) Year Global sea level change (cm) 2150 Year Figure A1. (a) Projected global mean temperature when the concentration of CO, is stabilized following the's profiles and the WRESSO and 1000 profiles shown in Figure 4. CH4. N2O and SO2 emissions are assumed to remain constant at their 1990 levels and halocarbons follow an emissions scenario consistent with compliance with the Montreal Protocol until 2100 and then remain constant thereafter (i.e.. the reference case); (h) As for (a), but for global sea level change and central ice-melt parameters. All results were produced using the Wigley and Raper simple climate/sea level model (see IPCC TP SCM Year Figure A2. (a) The effect of different non-CO2 gas emission profiles on global temperature change for the $450 and $650 concentration profiles (see Figure 2). The solid lines give the "reference" results; the short dashed lines the "CO, alone" results and the long dashed lines give results where CH4. N2O and SO2 emissions increase according to IS92a to 2100 and then stabilize (the "IS92a case"). The climate sensitivity is assumed to be the mid-range value of 2.5°C: (b) As for (a), but for global sea level change. Central values of the ice-melt parameters are assumed. See Figure 12 for results from 1990 to 2100. |