Imprecise Probability Analysisfor Integrated Assessmentof Climate ChangeD I S S E R T A T I O Nzur Erlangung des akademischen Grades\doctor rerum naturalium"(Dr. rer. nat.)in der Wissenschaftsdisziplin\Theoretische Physik"eingereicht an derMathematisch-Naturwissenschaftlichen Fakultatder Universitat Potsdamvorgelegt vonElmar KrieglerPotsdam, im Februar 2005When there is little information on which to base our conclusions, wecannot expect reasoning (no matter how clever or thorough) to reveal amost probable hypothesis or a uniquely reasonable course of action. Thereare limits to the power of reason.Peter Walley, 1991,in Statistical Reasoning with Imprecise Probabilities, London, pg. 2In a predestinate world, decision would be illusory; in a world of perfectforeknowledge, empty; in a world without natural order, powerless. Ourintuitive attitude to life implies non-illusory, non-empty, non-powerlessdecision... Since decision in this sense excludes both perfect foresightand anarchy in nature, it must be de ne d as choice in face of boundeduncertainty.George L.S. Shackle, 1961,in Decision, Order, and Time in Human A airs , Cambridge, pg. 43AbstractWe present an application of imprecise probability theory to the quanti cation of uncertainty inthe integrated assessment of climate change. Our work is motivated by the fact thattyabout climate change is pervasive, and therefore requires a thorough treatment in the integratedassessment process.