Paul Behrens is an environmental scientist whose research focuses on food systems, climate change, energy systems and sustainability transitions. He is a British Academy Global Professor at the Oxford Martin School, University of Oxford. His work examines the environmental impacts of dietary change, food systems and energy use, and has appeared in journals including Nature Food, Nature Energy and PNAS. He is the author of The Best of Times, The Worst of Times and co-editor of Food and Sustainability.
Early life and education Behrens studied physics and astronomy (MSci) at the University of Sheffield before completing a PhD in physics at the University of Auckland. His doctoral research focused on remote sensing of wind in complex terrain. He investigated why remote wind sensing instruments, such as sodar, deviate from traditional cup anemometers in complex terrain, showing that wind curvature and spatial separation significantly affect measurement accuracy and that these errors can often be corrected using potential flow modelling rather than computational fluid dynamics methods. Early in his career, Behrens worked as an astronomer with the Isaac Newton Group and held teaching and policy roles in New Zealand, including at the Royal Society of New Zealand and as an adjunct faculty member at Victoria University of Wellington.
Career and research Before joining Oxford, Behrens worked at Leiden University, where his research included environmental change, industrial ecology, food systems and energy systems, with a particular focus on the environmental impacts of dietary change, resource use and sustainability transitions. He was an assistant professor in energy and environmental change at Leiden. In his 2022 TEDxLeidenUniversity talk, Behrens explored how social tipping points could accelerate collective action on climate change and help avoid the worst environmental outcomes. In 2024, Behrens joined the Oxford Martin School in the Social Sciences Division of the University of Oxford as a British Academy Global Professor. His research examines the environmental and social impacts of food system transformation, including dietary change, land use and sustainability transitions. In 2025, Behrens was appointed Reapra senior research fellow at the University of Oxford's Wellbeing Research Centre, where his work focuses on sustainable wellbeing, food system transformation, and the environmental and social foundations of human flourishing.
Research contributions Behrens' research has examined plant-based diets, agricultural emissions, renewable energy systems, sustainability modelling and the links between climate change, consumption and human wellbeing.
Food systems and sustainability A 2022 Nature Food article co-authored by Behrens found that dietary change in high-income countries could reduce agricultural greenhouse gas emissions and create additional climate benefits through land restoration. In the same year, Behrens co-authored a Nature Food study arguing that wider adoption of plant-based diets in Europe could improve food system resilience during the Russia–Ukraine conflict while reducing greenhouse gas emissions, water use and pressure on agricultural land. He has also published on agricultural policy and the environmental implications of animal product consumption in Europe. Behrens has also co-authored research on vertical farming, including a 2025 Frontiers in Plant Science paper modelling how crop breeding and sink-limited plant growth may constrain future vertical farming yields.
Energy systems and decarbonisation Behrens has researched electricity systems, water use and energy transitions. In 2017, he led a Nature Energy study on the vulnerability of European electricity generation to water stress under climate change. His later research has included work on renewable energy land use, electricity sector emissions and the material requirements of energy transitions. In a 2018 Energy Policy paper, Behrens examined the land use intensity of different energy systems and argued that renewable energy systems generally require more space than fossil fuel generation, though with substantially lower pollution impacts. In a 2023 commentary in Joule, he argued that a transition to renewable energy would likely require substantially less overall mining activity than the current fossil fuel energy system, particularly because fossil fuels require continuous extraction while many transition minerals remain available for reuse and recycling.
Environmental impacts of consumption Behrens has contributed to research using consumption-based and input-output methods to study environmental pressures associated with trade, diets, materials and household consumption. In 2025, Behrens co-authored a Scientific Data paper presenting the agricultural product-specific ammonia emission dataset, a high-resolution European dataset of ammonia emissions from crop groups, grass types and livestock types. The study estimated that European agriculture emitted 3.5 Tg NH3-N in 2017, with dairy cattle, other cattle and swine responsible for 66% of total emissions, and major crop and grassland products including wheat, barley, maize, rapeseed and permanent grassland contributing 14%. In 2026, Behrens co-authored a Nature Food study estimating that reduced animal-sourced food consumption in the EU27 and the UK could strand substantial agricultural assets, including livestock, feed production assets, buildings, machinery and equipment. The study estimated that animal-sourced food assets represented 78% of fixed agricultural assets in the EU27 and the UK, and modelled potential stranded fixed assets of €61 billion, €168 billion and €255 billion under moderate, low and zero animal-sourced food scenarios respectively. Behrens' research on livestock emissions and dietary change has also been cited in discussions about the environmental impacts of grass-fed and grain-fed beef production.
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