Prof. Dr. Hermann Held

Integrated Assessment of climatic change mitigation options; interdiscipli¬nary work on climate and economy; assessment of insurance schemes. Integrated modelling in multi-disciplinary settings; uncertainty propagation in complex non-linear Earth system models. Development of methodologies for the derivation of robust (climate policy) advice from coupled complex models under heterogeneous uncertainty. In that context: Generalisations of probability theory to softer (generally non-additive) meas¬ures such as possibility functions; sampling strategies for complex models, adapted to such measures; time-series analysis (AR-modelling); predictability.

Professional employment and academic education:

Since 2010     Professor at the University of Hamburg (W3) / departments of geosciences and macroeconomics; Head of the Research Unit ‘Sustainability & Global Change’ at the Center for Earth System Research & Sustainability

2007 - 2010    Department head (jointly with O. Edenhofer) on ‘Sustainable Solutions’ at PIK (Potsdam Institute for Climate Impact Research e.V.)

2003 - 2007     Co-Lead of a Junior Research Group by the VolkswagenFoundation at PIK

1999 - 2003     PostDoc at PIK

1998 - 1999    PostDoc at UC Berkeley (in environmental physics) & freelancer (in environmental management) at Lawrence Berkeley National Lab

1996 - 1998     Senior Scientist and C1 (quasi Assistant Prof.) at University of Munich

1996,  1993     Dissertation and diploma thesis at the University of Munich

1986 - 1993     Study of physics at University of Kiel, ETZ Zurich, University of Munich

Honours, distinctions and awards, scholarships, medals:

1998 - 1999     Feodor Lynen-Fellow of the Alexander von Humboldt-Foundation

1996,  1993     Dissertation with ‘summa cum laude’, diploma ‘with distinction’

1993 - 1996     Scholarship by the Max Planck Society

1986 - 1993     Scholarship by the Studienstiftung des Deutschen Volkes (German National Academic Foundation)

Supervisions:

Since 2010      3 officially attributed Ph.D. supervisions started

Since 1995     Co-supervision of 7 further Ph.D. theses and 5 diploma theses (1 contributed to a WE-Heraeus-Prize)

Selected community services:

Since 2011      Member of the Scientific Advisory Board of the Wegener Center for Climate and Global Change (www.wegcenter.at ) at the University of Graz, Austria

Since 2011      Member of the CliSAP (climate cluster of excellence at the KlimaCampus Hamburg; http://www.klimacampus.de/ ) Scientific Steering Committee.

Since 2010      Lead Author for Chapter 2 on ‘Integrated Risk and Uncertainty Assessment of Climate Change Response Policies’, IPCC-WGIII, Fifth Assessment Report

Since 2010      Editorial Board Member of ‘Earth System Dynamics’

          2009      Coordinator Germany in an EIT(European Institute of Innovation & Technolo-gy)-KIC-proposal on climate, granted in December 2009 (since 2010 serving as EIT-representative for the University of Hamburg)

2005 - 2009     Maximum term elected president for EGU-ERE (European Geoscience Union – Energy, Resources and the Environment) – now vice president

H. S. Choi, U. A. Schneider, L. Rasche, J. Cui, E. Schmid, H. Held, Potential effects of perfect seasonal climate forecasting on agricultural markets, welfare and land use: a case study of Spain, Agricultural Systems, 133, 177-189 (2015).

D. Neubersch, H. Held, A. Otto, Operationalizing climate targets under learning: An application of cost-risk analysis, Climatic Change, 126 (3), 305-318, DOI 10.1007/s10584-014-1223-z (2014).

H. Held, F.-W. Gerstengarbe, T. Pardowitz, J. G. Pinto, U. Ulbrich, K. Born, M. G. Donat, M. K. Karremann, G. C. Leckebusch, P. Ludwig, K. M. Nissen, H. Österle, B. F. Prahl, P. C. Werner, D. J. Befort, O. Burghoff, Projections of global warming-induced impacts on winter storm losses in the German private household sector, Climatic Change, 121, 195-207, DOI 10.1007/s10584-013-0872-7 (2013).

M. G. W. Schmidt, H. Held, E. Kriegler, A. Lorenz, Stabilization Targets under Uncertain and Heterogeneous Climate Damages, Environmental & Resource Economics, 54, 79-99, DOI 10.1007/s10640-012-9582-2 (2013).

A. Lorenz, M. G. W. Schmidt, E. Kriegler, H. Held, Anticipating Climate Threshold Damages, Environmental Modeling and Assessment, 17 (1), 163-175, DOI: 10.1007/ s10666-011-9282-2, in Special Issue on Modeling Uncertainty in Energy Policy and the Economics of Climate Change (2012).

M. G. W. Schmidt, A. Lorenz, H. Held, E. Kriegler, Climate Targets under Uncertainty: Challenges and Remedies, Climatic Change Letters, 104 (3-4), 783-791, DOI 10.1007/s10584-010-9985-4 (2011).

H. Held, E. Kriegler, K. Lessmann, O. Edenhofer, Efficient Climate Policies under Technology and Climate Uncertainty, Energy Economics 31, S50–S61 (contribution in C. Böhringer, T. P. Mennel, T. F. Rutherford (Guest Eds.): Technological Change and Uncertainty in Environmental Economics), doi:10.1016/j.eneco.2008.12.012 (2009).

M. Scheffer, J. Bascompte, W. Brock, V. Brovkin, S. Carpenter, V. Dakos, H. Held, E. van Nes, M. Rietkerk, G. Sugihara, Early warning signals for critical transitions, Nature, 461, 53-59, doi:10.1038/nature/08227 (2009).

T. M. Lenton, H. Held, E. Kriegler, J. Hall, W. Lucht, S. Rahmstorf, H. J. Schellnhuber, Tipping elements in the Earth’s climate system, PNAS, 105 (6), 1786-1793, www.pnas.org/cgi/doi/10.1073/pnas.0705414105 (2008).

H. Held, T. Kleinen, Detection of climate system bifurcations by degenerate fingerprint¬ing, Geophys. Res. Lett. 31, L23207, doi:10.1029/2004GL020972 (2004).

Topics

• Reduction of uncertainty in global mean temperature projections and triggering of abrupt climate transitions
• derivation of economically optimal mitigation portfolios under uncertainty
• risk management of side-effects of climate solutions
• insurance solutions within the context of climatic change
• overall facilitation of transdisciplinary integration between climate science and economics.

Accomplishments

The first phase within climate research was devoted to the reduction of uncertainty in climate (impact) projections. Initiation and lead of a research project to reduce uncertainty of climate sensitivity by nonlinear assimilation of paleo data, using an Earth system model of intermediate complexity. It was demonstrated that a dynamically consistent assimilation of paleo data has the potential to reduce the uncertainty of climate sensitivity by a factor of 2 and to convert the high-end fat tail of the sensitivity’s distribution into a slim one. A similar approach was demonstrated for the determination of ocean heat uptake. 

For the continental level an early warning system for reaching climate-dynamical saddle node bifurcations was developed.

Then a modeling suite based on state-of-the-art coupled energy-economic growth-climate kernels was developed that would allow to absorb such types of insights on uncertainty and derive their effect on optimal economic investments.

The representation of deep uncertainty as Knightian uncertainty was advanced in discussing various approaches in the context of generalized Bayesian learning. Two new update rules were introduced that mimic society’s preferences better when having to deal with the advent of new information in a situation of deep uncertainty such as for the climate problem.

Finally market-based risk management tools were analyzed for geological carbon storage (presented during hearings of parliaments at the national and county level) and climate-induced increases in storm losses within the building sector (stakeholder project with the German insurance association). Global warming within the 21^st century was found a manageable issue at the national level for that sector.