Paul Behrens

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 TED xLeidenUniversity 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.

Food systems, obesity and climate change In 2025, Behrens co-authored a review published by Frontiers in Science examining the links between obesity, ultra-processed food and climate change. The paper argued that obesity and climate change are interconnected crises driven by unsustainable food systems, particularly diets high in ultra-processed foods and animal-sourced foods. It proposed policy responses including food system reform, taxation of "unhealthy foods", improved food labelling and shifting toward plant-rich diets.

Behrens has also examined the sustainability implications of reducing sugar intake. In a 2024 PNAS perspective, he and co-authors argued that lower added-sugar consumption could provide public health benefits while creating environmental opportunities through land restoration, alternative crop production, microbial protein, biofuels or bioplastics.

Climate policy modelling and wellbeing In 2025, Behrens co-authored a review in The Lancet Planetary Health examining how climate change impacts on human wellbeing are represented in integrated environment–society–economy models. It found that although climate change affects areas including health, food security, labour, migration, conflict, biodiversity and inequality, many commonly used climate policy models include a limited range of such wellbeing impacts.

Behrens has also co-authored work on alternative measures of societal progress. In 2024, he contributed to a Scientific Data paper introducing a "WISE database", a "beyond GDP" dataset covering wellbeing, inclusion and sustainability metrics across countries and country groupings.

Public engagement and policy communication Behrens has written and spoken publicly on climate change, food systems and energy transitions. The Oxford Martin School lists his commentary in BBC News, Thomson Reuters and Politico. The Guardian has also reported on his efforts to connect climate communication with sport and public engagement.

In 2021, Behrens wrote an opinion essay for Politico assessing best- and worst-case outcomes from the COP26 climate conference and discussing climate policy, energy transition, food systems and citizens' assemblies. Behrens was also among the scientists publicly supporting the Climate and Nature Bill, a proposed UK law intended to create a integrated, science-led climate and biodiversity strategy informed by a citizens' assembly, and assisted the launch of a Nature and National Security Bill in May 2026. In June 2024, Behrens interviewed Lord Deben, former chair of the UK Climate Change Committee, at an event organised by "Wycombe MP Watch" on the economic and social importance of accelerating climate action.

At Leiden University, Behrens developed teaching materials and local action exercises designed to help students engage with environmental issues through practical activities connected to academic disciplines. A related online course, The Great Sustainability Transition, was distributed via FutureLearn and Coursera.

In 2024, he was among a group of scientists who criticised a Food and Agriculture Organization report on livestock emissions, arguing that it underestimated the potential contribution of dietary change to reducing agricultural greenhouse gas emissions. In 2025, Behrens was among scientists who wrote to New Zealand Prime Minister Christopher Luxon, criticising proposals to weaken the country's agricultural methane targets, arguing that methane emissions reductions were necessary to limit near-term global warming.

In November 2025, Behrens was one of nine experts who delivered evidence at a National Emergency Briefing on climate and nature at Central Hall, Westminster before an audience of MPs, civil servants, business leaders and civic representatives. His briefing focused on food security and the risks posed to food systems by climate change and nature loss. The event was later adapted into The People's Emergency Briefing, a short film intended for community screenings narrated by wildlife presenter, Chris Packham.

In 2026, Behrens commented on the vulnerability of global food systems during the Iran conflict. He argued that disruption to fossil fuel supplies and fertiliser markets could trigger global food price shocks, highlighting the dependence of modern agriculture on energy-intensive supply chains.

In January 2026, Behrens gave oral evidence to the House of Commons Science, Innovation and Technology Committee inquiry on innovation and global food security, highlighting climate risks to food systems and the need for more plant-rich diets, resilient agriculture, and targeted food technologies.

Books and publications Behrens is the author of The Best of Times, The Worst of Times: Futures from the Frontiers of Climate Science, published by Indigo Press in 2021. He is also an editor and author of Food and Sustainability, an interdisciplinary textbook published by Oxford University Press in 2020.

Awards and honours In 2019, Behrens was named Leiden University's 2018 Discoverer of the Year, an award voted on by the public. Behrens and collaborators won the International Champion award in the 2023 Frontiers Planet Prize for research on dietary shifts and climate mitigation. In 2024, he was awarded a four year British Academy Global Professorship for research on food system transformation.

Selected publications

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