Open Letter


Scientists call for a Plant Based Treaty in efforts to avert a climate catastrophe

We, the undersigned, call on governments around the world to adopt and implement a Plant Based Treaty as a crucial step in addressing the escalating climate catastrophe.

We are asking governments to listen to and act on the science, which consistently demonstrates the grave threat posed to humanity by runaway climate change and highlights the instrumental role food systems have in both contributing to, and being able to mitigate, the growing climate and ecological crisis.

Our house is on fire. Climate change is currently the biggest threat to humanity and action is urgently needed [1]. Our food systems — particularly animal agriculture — are contributing heavily to soaring greenhouse gas emissions, increased frequency and severity of weather extremes, drought, widespread crop failures, loss of critical ecological lifelines, rapid biodiversity decline and are a large-scale threat to food security and human wellbeing globally [2].

Addressing fossil fuels alone — while critically imperative for survival — is not enough if we are to meet targets of limiting global overheating to 1.5°C, as set out in the Paris Agreement [3]. We must directly address the catastrophic impact of animal agriculture and work towards food system transformation as a matter of utmost urgency.

‘Code Red’ for humanity

Our food systems are a major driver of climate change, responsible for approximately 35% of all human-driven greenhouse gas emissions [3] and up to a third of all global deforestation. Animal agriculture is a major source of carbon dioxide, methane and nitrous oxide as well as being a significant consumer of limited critical resources such as land and water [2, 4]. Agriculture is a principal driver of accelerating biodiversity loss, with land conversion for animal grazing alongside growing of crops for animal feed responsible for widespread habitat and biodiversity decline [10]. We are also facing large-scale ocean dead zones and a rapid loss of critical marine ecosystems due to industrial overfishing.

Several peer-reviewed studies highlight that if global meat consumption continues on projected trajectories, agricultural emissions will take up the entire world’s carbon budget by 2050, with animal agriculture a major contributor [6]. The Intergovernmental Panel on Climate Change (IPCC) highlights the absolutely critical need to tackle greenhouse gas emissions from animal agriculture, particularly methane, which has a warming effect 80 times more powerful on the planet. Lead reviewer of the IPCC, Durwood Zaelke, said methane reductions were most likely the “only way” of preventing a temperature rise of above 1.5°C. He warns that if this is not achieved, extreme weather patterns will increase and several planetary tipping points could be triggered, from which there is no coming back. Zaelke points out that “cutting methane is the biggest opportunity to slow warming between now and 2040. We need to face this emergency.”

Shift to plant-based

Even if all global fossil fuel emissions stopped immediately, emissions from our food systems alone would still tip us over the 1.5°C temperature rise by 2050 [4]. A shift to plant-based diets is a key climate change mitigation tool and has been widely supported by a range of academic and scientific institutions as an essential step in lessening the climate crisis. The IPCC state that a shift to plant-based would “significantly reduce” food-related greenhouse gas emissions and is a “major opportunity” to both mitigate and adapt to climate change [5], while a recent Oxford University study calculated that emissions from food systems could be reduced by around 70% with a plant-based shift [7].

Scientists have calculated that the environmental footprint of animal-based foods is significantly higher compared to that of plant-based foods; in some cases causing more than double the pollution levels [3].  Animal agriculture is responsible for around 66% of all food’s annual emissions, yet provides only 18% of calories [9]. A switch to plant-based diets and farming would enable us to live within key planetary boundaries while our population continues to grow.  As highlighted by Rob Bailey from Chatham House – an independent think tank – “preventing catastrophic warming is dependent on tackling meat and dairy consumption”. [8]

The science is clear, and the desire to move towards a better future is strong. We call on governments and policymakers to urgently commence negotiations to adopt and implement a Plant Based Treaty, laying out a binding global plan to:

  • Relinquish – Committing to no land use change, ecosystem degradation or deforestation for the purpose of animal agriculture.
  • Redirect – Actively transitioning away from animal based food systems to more sustainable plant-based food systems.
  • Restore – Actively restoring key ecosystems and reforesting the Earth.

We are urgently calling on governments to join us in acting to avert further climate catastrophe caused by animal agriculture before we irreversibly surpass planetary tipping points. It’s not too late we have the knowledge, tools and solutions to change our trajectory we just need global action to implement them.


Peter Carter, Director Climate Emergency Institute

Professor Danny Harvey, Dept of Geography, U of Toronto

Professor Julia Steinberger, University of Lausanne, Switzerland, IPCC lead author AR6 WG3

Natasha Maria, BA(Hons) MSc

William Ripple, PhD. Distinguished Professor of Ecology, Oregon State University

Marc Bekoff, Ph.D. University of Colorado, Boulder, Professor emeritus of Ecology and Evolutionary Biology

William B Orcutt, Capt. USAF Ret. BSEE University of Missouri, MSEE Air Force Institute of Technology

Lena Hannah Dogra, PhD Candidate in Physics, University of Cambridge

Didem Varol, RD

Diana Molina, LCG. (Genomic Sciences)

Cassandra Meisel Clarke, Msc. Biochemistry, MSc. Epidemiology

Gerard Wedderburn-Bisshop, B. Surv (Hons1), former Principal Scientist, Qld Natural Resources

Celia Deane-Drummond, MA (Cantab), PhD (Plant Science), PhD (Theology)

Dominik Linn, PhD Candidate in Industrial Mathematics (Fraunhofer ITWM and TUK)

Carolin Schellhorn, Ph.D.

Dr. Tushar Mehta

Dr. Amanda Boetzkes, Professor, Contemporary Art History and Theory, University of Guelph

Dr. Kurt Schmidinger, food scientist and geophysicist

Marc Bekoff, Ph.D.

Dr. Kurt Schmidinger, food scientist and geophysicist

Prof. Imre Szeman

Pamela Fergusson, RD, PhD

Dr. Thomas Brückmann, biologist & communication designer

Cameron Brick, PhD, University of Amsterdam

Nicholas Carter, ecologist, researcher and co-founder of

Professor Alexandra Cook FLS

Dr. Charles Greene

Dr. Mark Terry

Dr Charlie Gardner

Dr A J Perrin

Professor James Renwick

Charles Ross DO

Brenda Dobia, PhD

Psychologist, Social Ecologist, Adjunct Fellow Wester Sydney University

Annika Linde, DVM, PhD, MPH. Western University of Health Sciences, California

David Crookall, PhD, Inter- Ocean-Climate School (IOCS), Ocean Open University

David Howden, PhD

Dr. Fatih Uenal, Center for Affective Sciences, University of Geneva

Jeroen Melief, PhD

Hon Prof Colin D Butler, National Centre for Epidemiology and Population Health, Australian National University

Jill Belch, Professor of Medicine and Lead, Tayside Air Pollution Research Project

Dr. Heather Davis

Dr. Yuri Engelhardt, Senior Lecturer, Lund University Centre for Sustainability Studies

Cameron Roberts, PhD

Paul Berger, Associate Professor (Education), Lakehead University

Pere Pons, Associate Professor, University of Girona

André Bittar, Research Associate, King’s College London

Jans Henke, MSc

Zahra Kassam, MBBS, FRCP(C), FRCR(UK). Oncologist, University of Toronto, Canada

Dr. Anna Perreira

Dr Corey Lee Wrenn

Patrick Alberti, M.A.

Kathrin Herrmann, Johns Hopkins University Center for Alternatives to Animal Testing

Jane Hindley, Senior Lecturer in Interdisciplinary Studies, University of Essex

Dr Holly Sitters, Ecologist, The University of Melbourne

Bastiaan Rutjens, PhD

Didem Aydurmus, PhD (climate politics)

Dr. Kristiina Visakorpi

Carla Steffen, Veterinarian

Dr Pravakar Mohanty

Dr Anoop Shah

José Moisés Martín Carretero, Professor of Economics. Faculty of Science and Technology, University Camilo José Cela

Barton Rubenstein, PhD, Mother Earth Project cofounder

Jonathan M. White, PhD, Assoc. Professor of Sociology, Bentley University

John Packer, Associate Professor (Law), University of Ottawa

Dr. J. David Spence, Professor of Neurology and Clinical Pharmacology, Western University

Chloe Taylor, Professor of Women’s and Gender Studies, University of Alberta

Laurie Adkin, Professor [Political Science and Environmental Studies] University of Alberta

Dr. Karim Zantout

Dr. Alexandra Isfahani-Hammond

Massimiliano Fabbricino, professore Ordinario Università di Napoli Federico II

David Krantz, MJ, MPA, MA, PhD(c)

Dr. Selena Couture, University of Alberta, Dept of Drama

Dr. Sascha Holzhauer, Systems Scientist, University of Kassel

Dr. Sarah Krotz

Disa Sauter, University of Amsterdam

Dr. Orr Karassin, Senior Lecturer, Public Policy, The Open Univeristy of Israel

Alfred-Wegener-Institut Helmholtz-Zentrum für Polar- und Meeresforschung

Dominique Bourg, Honorary Professor

Jesus Martinez-Garcia, University of Essex

Dr. Donald Drake

Clelia Cascella, Manchester University

Tracy Timmins, BSc (Hon), MSc

Dr. Jessica Claudio, Hixson, USA

Eleanor Georgiadis, Ph.D (Paleoceanography, biology), University of Oxford

Sena Crutchley, MA, CCC-SLP

Dr. Juan F. Masello, Justus Liebig University Giessen

Saverio Maviglia, MD, Boston, USA

Yagmur Ozdemir, Physics Engineer, Ankara University, Turkey

Samantha Miller, Biotech Scientist, Piedmont, United States

Shelly Ryan, MA,  Middletown, USA

Dr. Fredric Litt, Sagamore Hills OH, USA

Dierck-Ekkehard Liebscher, Potsdam, Germany

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[1] World Economic Forum, “The Global Risks Report 2020,” Insight Report (World Economic Forum; Marsh & McLennan; Zurich Insurance Group; National University of Singapore; Oxford Martin School; Wharton Risk Management and Decision Processes Center, University of Pennsylvania, 2020)

[2] Wellesley, Happer and Froggat (2015), Changing Climate, Changing Diets: Pathways to Lower Meat Consumption [online]
Available at:

[Accessed 23rd September 2021]

[3] Xu, X., Sharma, P., Shu, S., Lin, T.S., Ciais, P., Tubiello, F.N., Smith, P., Campbell, N. and Jain, A.K., 2021. Global greenhouse gas emissions from animal-based foods are twice those of plant-based foods. Nature Food, 2(9), pp.724-732.

[4] Clark, M.A., Domingo, N.G., Colgan, K., Thakrar, S.K., Tilman, D., Lynch, J., Azevedo, I.L. and Hill, J.D., 2020. Global food system emissions could preclude achieving the 1.5 and 2 C climate change targets. Science, 370(6517), pp.705-708.

[5] IPCC sixth assessment –

[6] Bajželj, B., Richards, K.S., Allwood, J.M., Smith, P., Dennis, J.S., Curmi, E. and Gilligan, C.A., 2014. Importance of food-demand management for climate mitigation. Nature Climate Change, 4(10), pp.924-929.

[7] Plant-based diets could save millions of lives and dramatically cut greenhouse gas emissions:

[8] Eating less meat essential to curb climate change, says report:


[10] Food system impacts on biodiversity loss: