A new climate dataset for systematic assessments of climate change impacts as a function of global warming

J Heinke,M Meinshausen,C Müller,D Gerten,W Lucht,S Ostberg,S Schaphoff,K Frieler

doi:10.5194/gmd-6-1689-2013

Abstract

Abstract. In the ongoing political debate on climate change, global mean temperature change (ΔTglob) has become the yardstick by which mitigation costs, impacts from unavoided climate change, and adaptation requirements are discussed. For a scientifically informed discourse along these lines, systematic assessments of climate change impacts as a function of ΔTglob are required. The current availability of climate change scenarios constrains this type of assessment to a narrow range of temperature change and/or a reduced ensemble of climate models. Here, a newly composed dataset of climate change scenarios is presented that addresses the specific requirements for global assessments of climate change impacts as a function of ΔTglob. A pattern-scaling approach is applied to extract generalised patterns of spatially explicit change in temperature, precipitation and cloudiness from 19 Atmosphere–Ocean General Circulation Models (AOGCMs). The patterns are combined with scenarios of global mean temperature increase obtained from the reduced-complexity climate model MAGICC6 to create climate scenarios covering warming levels from 1.5 to 5 degrees above pre-industrial levels around the year 2100. The patterns are shown to sufficiently maintain the original AOGCMs' climate change properties, even though they, necessarily, utilise a simplified relationships between ΔTglob and changes in local climate properties. The dataset (made available online upon final publication of this paper) facilitates systematic analyses of climate change impacts as it covers a wider and finer-spaced range of climate change scenarios than the original AOGCM simulations.

Highlights

Impacts of anticipated future climate change on ecosystems and human societies are reason for major concern
The scaling patterns extracted from Atmosphere–Ocean General Circulation Models (AOGCMs) simulations are the core component of the scenario-building described in this paper
The dataset combines observations, information extracted from AOGCM simulations, and results from a reduced complexity climate model into physically plausible climate change scenarios for a wide range of global mean temperature increases

Summary

Introduction

Impacts of anticipated future climate change on ecosystems and human societies are reason for major concern. For example, by the Intergovernmental Panel on Climate Change’s Working Group II report (Parry et al, 2007), assessments commonly lack systematic quantification of impacts as a function of global warming, as only a small and often opportunistic selection of available climate change scenarios is employed. This hampers direct comparisons between studies (e.g. Müller et al, 2011) and our understanding of how impacts and their likelihood change over time or as a function of global mean temperature (Tglob). Compilations of individual impact studies have helped to illustrate the underlying “reasons for Published by Copernicus Publications on behalf of the European Geosciences Union

Methods

Results

Conclusion