Berlin 2015 – scientific programme

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SYPS: Symposium Physics of Sustainability and Human-Nature Interactions

SYPS 1: Physics of Sustainability and Human-Nature Interactions

SYPS 1.2: Invited Talk

Wednesday, March 18, 2015, 10:00–10:30, H 0105

Climate investment under uncertainty: the two degree target and the desire for dynamic consistency — •Hermann Held and Delf Neubersch — Center of Earth System Research and Sustainability, University of Hamburg, Grindelberg 5, 20144 Hamburg

During the climate Conferences of the Parties 2009-2011 the global community developed a formal consensus to limit the anthropogenically induced increase of global mean temperature to 2K (“two-degree targe” or “2^∘-target”). While the latest IPCC (Intergovernmental Panel on Climate Change) report (2014) summarizes cost estimates that can be interpreted as rather low, suggesting some potential political feasibility of the 2^∘-target, some authors start to question the conceptual validity of the 2^∘-target: it might be too late to still comply with it, given the slow pace of mitigation policy. Moreover, it is pointed out that a strictly interpreted temperature target does not have a straightforward generalization when uncertainty is internalized in decision-making under anticipated future learning.

Here we present a generalization of the 2^∘-target that addresses both of these problematic aspects and that respects dynamic consistency under anticipated future learning. Consequences for climate policy are highlighted. We find that previous climate economic analyses of the 2K-target in terms of low cost for transforming the energy system are still valid, when being re-interpreted. Moreover, mitigation costs could be reduced by up to 1/3 if the climate response to greenhouse gas forcing were known with certainty, pointing to the expected economic value of geo-scientific information.