Climatic Change

, Volume 104, Issue 2, pp 255-285

First online:

How well do integrated assessment models simulate climate change?

  • Detlef P. van VuurenAffiliated withNetherlands Environmental Assessment Agency Email author 
  • , Jason LoweAffiliated withMetOffice Hadley CentreDepartment of Meteorology, The University of Reading
  • , Elke StehfestAffiliated withNetherlands Environmental Assessment Agency
  • , Laila GoharAffiliated withMetOffice Hadley CentreDepartment of Meteorology, The University of Reading
  • , Andries F. HofAffiliated withNetherlands Environmental Assessment Agency
  • , Chris HopeAffiliated withJudge Business School, Cambridge University
  • , Rachel WarrenAffiliated withTyndall Centre, School of Environmental Sciences, University of East Anglia
  • , Malte MeinshausenAffiliated withPotsdam Institute for Climate Impact Analysis
  • , Gian-Kasper PlattnerAffiliated withEnvironmental Physics, Institute of Biogeochemistry and Pollutant Dynamics, ETH ZürichClimate and Environmental Physics, Physics Institute, University of Bern

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Integrated assessment models (IAMs) are regularly used to evaluate different policies of future emissions reductions. Since the global costs associated with these policies are immense, it is vital that the uncertainties in IAMs are quantified and understood. We first demonstrate the significant spread in the climate system and carbon cycle components of several contemporary IAMs. We then examine these components in more detail to understand the causes of differences, comparing the results with more complex climate models and earth system models (ESMs), where available. Our results show that in most cases the outcomes of IAMs are within the range of the outcomes of complex models, but differences are large enough to matter for policy advice. There are areas where IAMs would benefit from improvements (e.g. climate sensitivity, inertia in climate response, carbon cycle feedbacks). In some cases, additional climate model experiments are needed to be able to tune some of these improvements. This will require better communication between the IAM and ESM development communities.