From attribution to expectations of marine range shifts to anthropogenic climate change

Elvira Poloczanska1, Christopher Brown2, Michael Burrows3, Jorge García Molinos4, Ove Hoegh-Guldberg5 Hans-Otto Pörtner6

(1) CSIRO Oceans and Atmosphere, Queensland Biosciences Precinct, St Lucia, Qld 4067, Australia
(2) Australian Rivers Institute, Griffith Univeristy, 170 Kessels Road, Nathan Qld 4111, Australia
(3) Scottish Association for Marine Science, Oban, Argyll PA37 1QA, UK.
(4) Center for Environmental Biology and Ecosystem Studies, National Institute for Environmental Studies, 16-2 Onogawa, Tsukuba, Ibaraki 305-8506, Japan.
(5) The Global Change Institute, University of Queensland, Brisbane, Queensland 4072, Australia.
(6) Alfred Wegener Institute, D-27570 Bremerhaven, Germany

Detection of the impacts of changing climate on marine systems is growing, however attribution of ecological changes and subsequent responses in human systems to anthropogenic climate change is more challenging. We draw on Working Group II of the IPCC Fifth Assessment Report and supplementary research to discuss evidence and attribution of marine range shifts. Climate-driven range shifts are reported from every ocean. We apply vote-counting to provide convincing evidence of a global imprint of climate change on natural systems as a form of attribution. Explicit attribution of individual impacts to anthropogenic climate change are rare and often involve statistical or mechanistic models coupled with climate model simulations. However, qualitative approaches to attribution, encompassing multiple lines of evidence, reduce reliance on explicit modelling. Attribution can be described as a causal chain from anthropogenic changes in climate through to responses in ecological and human systems and can be traced through the application of appropriate frameworks. Meta-analysis can also provide convincing evidence of the role of climate change. We show through meta-analysis that marine biodiversity is shifting at 30.6 km per decade. We provide further evidence that marine range shifts are related to climate change velocities (distributional shifts in thermal conditions) therefore maps of the velocity of climate change, and its extension velocity trajectories, could be applied to generate expectations for range shifts and highlight where approaches to facilitate range shifts may be most effective