The tolerable windows approach to climate control: Optimization, risks, and perspectives

Scientists working in the field of global warming are subject to the increasing tension between soundly based scientific research and the political necessity for the formulation of adequate climate protection strategies. This narrow route between Scylla and Charybdis, which has to prevent science both from withdrawing into its traditional ivory tower and becoming lost in the maelstrom of unbased political claims, demands a well-defined borderline between normative settings and the strict analysis of the Earth System. The borderline is sketched in Article 2 of the Framework Convention on Climate Change (FCCC): “… stabilization of greenhouse gas concentrations in the atmosphere at a level that would prevent dangerous anthropogenic interference with the climate system. Such a level should be achieved within a time frame sufficient to allow ecosystems to adapt naturally to climate change, to ensure that food production is not threatened, and to enable economic development to proceed in a sustainable manner” (UN, 1992; emphasis added). It is the task of science to find out how this political constraint can be fulfilled. It is important, however, to keep in mind that — similar to Odysseus — the route outlined by Article 2 is subject to continuous corrections and thus has to be followed by fuzzy control. This is due both to the fact that norms, settings, and society itself are changing quite rapidly, and to the uncertainties in the knowledge of the mechanisms of the system.