Prof. Dr. Hans-Otto Pörtner was one of the Co-Chairs of Working Group II during the sixth assessment cycle. He is a physiologist and marine biologist performing research at the Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research (AWI) in Bremerhaven, where he heads the Integrative Ecophysiology Section. During his scientific career Hans-Otto Pörtner has developed ground-breaking theories on the impacts of ocean warming, ocean acidification and hypoxia on marine organisms and ecosystems, and has validated these in numerous studies. Two of his seminal topics involve the molecular, biochemical and physiological mechanisms that determine the tolerance, performance and adaptive capacity of marine animals, and whether and how these mechanisms apply universally to all animals, including humans. He is a Web of Science/Clarivate Analytics highly cited researcher (top 1% Cross-Field) 2018 onward.
Hans-Otto Pörtner was Coordinating Lead Author of Chapter 6 (Ocean Systems) of the Working Group II contribution to the IPCC Fifth Assessment Report, published in 2014, and was elected Co-Chair of Working Group II in 2015. Under his co-leadership Working Group II published the IPCC Special Report on Ocean and the Cryosphere in a Changing Climate (SROCC) in 2019 and contributed to the Special Reports on “Climate Change and Land” and “Global warming of 1.5°C”. In addition, he co-led the Scientific steering committee for the IPCC-IPBES co-sponsored workshop and report 2021 on “Biodiversity and Climate Change” and was a member of the Scientific Steering Committees of the IPCC-ICOMOS- UNESCO international co-sponsored meeting on Culture, Heritage and Climate Change, held in 2021.
Hans-Otto Pörtner is an elected member of the European Academy of Sciences and was appointed by the German government to its Advisory Council on Global Change (WBGU) in 2020.