Glob Change Biol. 2022;00:1–23. wileyonlinelibrary.com/journal/gcb | 1 © 2021 John Wiley & Sons Ltd Received: 6 October 2021 | Revised: 15 December 2021 | Accepted: 19 December 2021 DOI: 10.1111/gcb.16056 INVITED REVIEW How do we best synergize climate mitigation actions to co-benefit biodiversity? Pete Smith 1 | Almut Arneth 2 | David K. A. Barnes 3 | Kazuhito Ichii 4 | Pablo A. Marquet 5 | Alex Popp 6 | Hans-Otto Pörtner 7 | Alex D. Rogers 8,9 | Robert J. Scholes 10 | Bernardo Strassburg 11,12 | Jainguo Wu 13 | Hein Ngo 14 1 Institute of Biological and Environmental Sciences, University of Aberdeen, Aberdeen, UK 2 Atmospheric Environmental Research, Karlsruhe Institute of Technology (KIT), Garmisch-Partenkirchen, Germany 3 British Antarctic Survey, Cambridge, UK 4 Center for Environmental Remote Sensing (CeRES), Chiba University, Chiba, Japan 5 Center for Applied Ecology and Sustainability (CAPES), Pontificia Universidad Catolica de Chile, Santiago, Chile 6 Potsdam Institute for Climate Impact Research (PIK), Potsdam, Germany 7 Alfred Wegener Institute for Polar and Marine Research, Bremerhaven, Germany 8 Somerville College, University of Oxford, Oxford, UK 9 REV Ocean, Lysaker, Norway 10 Global Change Institute, University of the Witwatersrand, Johannesburg, South Africa 11 Rio Conservation and Sustainability Science Centre, Department of Geography and Environment, Pontifical Catholic University, Rio de Janeiro, Brazil 12 International Institute for Sustainability, Rio de Janeiro, Brazil 13 The Institute of Environmental Ecology, Chinese Research Academy of Environmental Sciences, Beijing, China 14 Food and Agriculture Organization of the United Nations (FAO), Rome, Italy Correspondence P. Smith, Institute of Biological and Environmental Sciences, University of Aberdeen, Aberdeen, UK. Email: pete.smith@abdn.ac.uk Abstract A multitude of actions to protect, sustainably manage and restore natural and modi- fied ecosystems can have co-benefits for both climate mitigation and biodiversity conservation. Reducing greenhouse emissions to limit warming to less than 1.5 or 2°C above preindustrial levels, as outlined in the Paris Agreement, can yield strong co- benefits for land, freshwater and marine biodiversity and reduce amplifying climate feedbacks from ecosystem changes. Not all climate mitigation strategies are equally effective at producing biodiversity co-benefits, some in fact are counterproductive. Moreover, social implications are often overlooked within the climate-biodiversity nexus. Protecting biodiverse and carbon-rich natural environments, ecological res- toration of potentially biodiverse and carbon-rich habitats, the deliberate creation of novel habitats, taking into consideration a locally adapted and meaningful (i.e. full consequences considered) mix of these measures, can result in the most robust win- win solutions. These can be further enhanced by avoidance of narrow goals, taking long-term views and minimizing further losses of intact ecosystems. In this review paper, we first discuss various climate mitigation actions that evidence demonstrates can negatively impact biodiversity, resulting in unseen and unintended negative con- sequences. We then examine climate mitigation actions that co-deliver biodiversity and societal benefits. We give examples of these win-win solutions, categorized as ‘protect, restore, manage and create’, in different regions of the world that could be expanded, upscaled and used for further innovation. KEYWORDS biodiversity, climate change mitigation, co-benefits, nature-based solutions, trade-offs