IDEA AND PERSPECTIVE Beyond climate change attribution in conservation and ecological research Camille Parmesan, 1,2 * Michael T. Burrows, 3 Carlos M. Duarte, 4,5,6 Elvira S. Poloczanska, 7 Anthony J. Richardson, 7,8 David S. Schoeman 9,10 and Michael C. Singer 2 Abstract There is increasing pressure from policymakers for ecologists to generate more detailed ‘attribution’ analyses aimed at quantitatively estimating relative contributions of different driving forces, including anthropogenic climate change (ACC), to observed biological changes. Here, we argue that this approach is not productive for ecological studies. Global meta-analyses of diverse species, regions and ecosystems have already given us ‘very high confidence’ [sensu Intergovernmental Panel on Climate Change (IPCC)] that ACC has impacted wild species in a general sense. Further, for well-studied species or systems, synthesis of experiments and models with long-term observations has given us similarly high confidence that they have been impacted by regional climate change (regardless of its cause). However, the role of greenhouse gases in driving these impacts has not been estimated quantitatively. Should this be an ecological research priority? We argue that development of quantitative ecological models for this purpose faces several impediments, particularly the existence of strong, non-additive interactions among different external factors. However, even with current understanding of impacts of global warming, there are myriad climate change adaptation options already developed in the literature that could be, and in fact are being, implemented now. Keywords Anthropogenic climate change, biodiversity, biological projections, climate change, climate change attribu- tion, conservation planning, ecological modelling, global warming, IPCC. Ecology Letters (2013) 16: 58–71 INTRODUCTION Detailed understanding of the mechanisms driving the global cli- mate system has resulted in a set of modelling and analytical approaches that is widely accepted by the climate science commu- nity. The result is a series of quantitative assessments of the rela- tive roles of natural and anthropogenic drivers of climate trends (Fig. 1, IPCC 2007a). Climate scientists have successfully provided analyses that yield ‘very high’ confidence [sensu Intergovernmental Panel on Climate Change (IPCC)] in attributing the bulk of the past 50 years’ rise in global mean temperatures to rises in human-caused greenhouse gases (GHG), (Fig. 1, see Box 1 for IPCC definitions of ‘confidence levels’ and ‘attribution’, IPCC 2007a). The policy sector drove that research, both in terms of funding priorities and in terms of IPCC mandates. The result has been an ever-increasing call for worldwide reductions in GHG emissions. With consensus that human activities are leading to dangerous interference in Earth’s climate (Rockstr€ om et al. 2009), there has been growing policy pressure for clear quantification and attribution of the resulting biological impacts. Encouraged by successful attri- bution of global warming to GHG, policymakers have advocated extension of this approach to generate quantitative attribution of biological events not merely to changing climate (CC), but specifi- cally to anthropogenic climate change (ACC), the component of change that has been driven by increase in GHG. When particular biological systems are dramatically altered, such as when a popula- tion goes extinct, policymakers (and the public) often demand a level of ‘attribution’ that clearly delineates the role of ACC from those of other potential drivers. A recent IPCC Guidance document for the Fifth Assessment Report attempted to satisfy this demand by developing a framework for detecting biological impacts and attributing them to anthropogenic GHG forcing (Box 1 and Hegerl et al. 2010). 1 Marine Institute, Level 3 Marine Bldg., Plymouth University, Drakes Circus Plymouth, Devon, PL4 8AA, UK 2 Integrative Biology, University of Texas, Austin, Texas,78712, USA 3 Scottish Association for Marine Science, Scottish Marine Institute, Oban, Argyll,PA37 1QA, UK 4 Department of Global Change Research, IMEDEA (CSIC-UIB), Instituto Mediterr aneo de Estudios Avanzados, Miquel Marqu es 21, Esporles, 07190, Spain 5 The UWA Oceans Institute and School of Plant Biology, University of Western Australia, 35 Stirling Highway, Crawley, WA, 6009, Australia 6 Faculty of Marine Sciences, King Abdulaziz University, P. O. Box 80207, Jeddah, 21589, Saudi Arabia 7 Climate Adaptation Flagship, CSIRO Marine and Atmospheric Research, Ecosciences Precinct, GPO Box 2583, Dutton Park, QLD, 4102, Australia 8 Centre for Applications in Natural Resource Mathematics (CARM), School of Mathematics and Physics, University of Queensland, St Lucia, QLD, 4072, Australia 9 Faculty of Science, Health, Education and Engineering, University of the Sunshine Coast, Maroochydore, QLD, 4558, Australia 10 Department of Zoology, Nelson Mandela Metropolitan University, Port Elizabeth, South Africa *Correspondence: E-mail: parmesan@uts.cc.utexas.edu © 2013 John Wiley & Sons Ltd/CNRS Ecology Letters, (2013) 16: 58–71 doi: 10.1111/ele.12098