A framework for ensemble modelling of climate change impacts on lakes worldwide: the ISIMIP Lake Sector
Authors: Golub Malgorzata , Thiery Wim , Marcé Rafael , Pierson Don , Vanderkelen Inne , Mercado Daniel , Woolway R. Iestyn , Grant Luke , Jennings Eleanor , Schewe Jacob , Zhao Fang , Frieler Katja , Mengel Matthias , Bogomolov Vasiliy Y. , Bouffard Damien , Couture Raoul-Marie , Debolskiy Andrey V. , Droppers Bram , Gal Gideon , Guo Mingyang , Janssen Annette B. G. , Kirillin Georgiy , Ladwig Robert , Magee Madeline , Moore Tadhg , Perroud Marjorie , Piccolroaz Sebastiano , Raaman Vinnaa Love , Schmid Martin , Shatwell Tom , Stepanenko Victor M. , Tan Zeli , Yao Huaxia , Adrian Rita , Allan Mathew , Anneville Orlane , Arvola Lauri , Atkins Karen , Boegman Leon , Carey Cayelan , Christianson Kyle , de Eyto Elvira , DeGasperi Curtis , Grechushnikova Maria , Hejzlar Josef , Joehnk Klaus , Jones Ian D. , Laas Alo , Mackay Eleanor B. , Mammarella Ivan , Markensten Hampus , McBride Chris , Özkundakci Deniz , Potes Miguel , Rinke Karsten , Robertson Dale , Rusak James , Salgado Rui , van den Linden Leon , Verburg Piet , Wain Danielle , Ward Nicole K. , Wollrab Sabine , Zdorovennova Galina 
Published: January 2022

Abstract. Empirical evidence demonstrates that lakes and reservoirs are warming across the globe. Consequently, there is an increased need to project future changes in lake thermal structure and resulting changes in lake biogeochemistry in order to plan for the likely impacts. Previous studies of the impacts of climate change on lakes have often relied on a single model forced with limited scenario-driven projections of future climate for a relatively small number of lakes. As a result, our understanding of the effects of climate change on lakes is fragmentary, based on scattered studies using different data sources and modelling protocols, and mainly focused on individual lakes or lake regions. This has precluded identification of the main impacts of climate change on lakes at global and regional scales and has likely contributed to the lack of lake water quality considerations in policy-relevant documents, such as the Assessment Reports of the Intergovernmental Panel on Climate Change (IPCC). Here, we describe a simulation protocol developed by the Lake Sector of the Inter-Sectoral Impact Model Intercomparison Project (ISIMIP) for simulating climate change impacts on lakes using an ensemble of lake models and climate change scenarios. The protocol prescribes lake simulations driven by climate forcing from gridded observations and different Earth system models under various Representative Greenhouse Gas Concentration Pathways, all consistently bias-corrected on a 0.5° × 0.5° global grid. In ISIMIP phase 2, 11 lake models were forced with these data to project the thermal structure of 62 well-studied lakes where data were available for calibration under historical conditions, and for nearly 17,500 lakes using uncalibrated models and forcing data from the global grid where lakes are present. In ISIMIP phase 3, this approach was expanded to consider more lakes, more models, and more processes. The ISIMIP Lake Sector is the largest international effort to project future water temperature, thermal structure, and ice phenology of lakes at local and global scales and paves the way for future simulations of the impacts of climate change on water quality and biogeochemistry in lakes.