Climate Change 2001: Synthesis Report

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Question 1

What can scientific, technical, and socio-economic analyses contribute to the determination of what constitutes dangerous anthropogenic interference with the climate system as referred to in Article 2 of the Framework Convention on Climate Change?

Natural, technical, and social sciences can provide essential information and evidence needed for decisions on what constitutes "dangerous anthropogenic interference with the climate system." At the same time, such decisions are value judgments determined through socio-political processes, taking into account considerations such as development, equity, and sustainability, as well as uncertainties and risk.

The basis for determining what constitutes "dangerous anthropogenic interference" will vary among regions -- depending both on the local nature and consequences of climate change impacts, and also on the adaptive capacity available to cope with climate change -- and depends upon mitigative capacity, since the magnitude and the rate of change are both important. There is no universally applicable best set of policies; rather, it is important to consider both the robustness of different policy measures against a range of possible future worlds, and the degree to which such climate-specific policies can be integrated with broader sustainable development policies.


The Third Assessment Report (TAR) provides an assessment of new scientific information and evidence as an input for policymakers in their determination of what constitutes "dangerous anthropogenic interference with the climate system." It provides, first, new projections of future concentrations of greenhouse gases in the atmosphere, global and regional patterns of changes and rates of change in temperature, precipitation, and sea level, and changes in extreme climate events. It also examines possibilities for abrupt and irreversible changes in ocean circulation and the major ice sheets. Second, it provides an assessment of the biophysical and socio-economic impacts of climate change, with regard to risks to unique and threatened systems, risks associated with extreme weather events, the distribution of impacts, aggregate impacts, and risks of large-scale, high-impact events. Third, it provides an assessment of the potential for achieving a broad range of levels of greenhouse gas concentrations in the atmosphere through mitigation and information about how adaptation can reduce vulnerability.

An integrated view of climate change considers the dynamics of the complete cycle of interlinked causes and effects across all sectors concerned (see Figure SPM-1). The TAR provides new policy-relevant information and evidence with regard to all quadrants of Figure SPM-1. A major new contribution of the Special Report on Emissions Scenarios (SRES) was to explore alternative development paths and related greenhouse gas emissions, and the TAR assessed preliminary work on the linkage between adaptation, mitigation, and development paths. However, the TAR does not achieve a fully integrated assessment of climate change because of the incomplete state of knowledge.

Climate change decision making is essentially a sequential process under general uncertainty. Decision making has to deal with uncertainties including the risk of non-linear and/or irreversible changes and entails balancing the risks of either insufficient or excessive action, and involves careful consideration of the consequences (both environmental and economic), their likelihood, and society's attitude towards risk.

Figure SPM-1: Climate change - an integrated framework. Schematic and simplified representation of an integrated assessment framework for considering anthropogenic climate change. The yellow arrows show the cycle of cause and effect among the four quadrants shown in the figure, while the blue arrow indicates the societal response to climate change impacts. See the caption for Figure 1-1 for an expanded description of this framework.

The climate change issue is part of the larger challenge of sustainable development. As a result, climate policies can be more effective when consistently embedded within broader strategies designed to make national and regional development paths more sustainable. This occurs because the impact of climate variability and change, climate policy responses, and associated socio-economic development will affect the ability of countries to achieve sustainable development goals. Conversely, the pursuit of those goals will in turn affect the opportunities for, and success of, climate policies. In particular, the socio-economic and technological characteristics of different development paths will strongly affect emissions, the rate and magnitude of climate change, climate change impacts, the capability to adapt, and the capacity to mitigate.


The TAR assesses available information on the timing, opportunities, costs, benefits, and impacts of various mitigation and adaptation option. It indicates that there are opportunities for countries acting individually, and in cooperation with others, to reduce costs of mitigation and adaptation and to realize benefits associated with achieving sustainable development.


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