1 The Challenge of Sustainable Agriculture
Agriculture has had a greater influence on the surface of the Earth than any other human activity (see Figure 1-1). More than one-third of the Earth’s ice-free surface is devoted to agriculture, and the portion is increasing as more land is converted to crop and livestock production.1 Of the water withdrawn from rivers, lakes, and aquifers, 70 percent goes to agriculture,2 and 20 percent of aquifers are already overexploited.3 As the global population and per capita income continue to increase, the pressure on land and water to provide food will grow.
Agriculture is the link between the natural world and the products and services that have made the modern world possible.
SOURCE: Food and Agriculture Organization of the United Nations. 2014. Guiding a Common Vision for Sustainable Food and Agriculture: Principles and Approaches, pp. 14–15, Figure 1. Rome, Italy: Food and Agriculture Organization of the United Nations. Reproduced with permission.
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1 Ramankutty, N., Z. Mehrabi, K. Waha, L. Jarvis, C. Kremen, M. Herrero, and L. H. Rieseberg. 2018. Trends in global agricultural land use: Implications for environmental health and food security. Annual Review of Plant Biology 69(1):789–815.
2 UNESCO (United Nations Educational, Scientific and Cultural Organization). 2020. United Nations World Water Development Report 2020: Water and Climate Change. Paris, France: UNESCO.
3 Gleeson, T., Y. Wada, M. F. P. Bierkens, and L. P. H. van Beek. 2012. Water balance of global aquifers revealed by groundwater footprint. Nature 488:197–200.
This extensive use of the Earth’s land and water has already had many deleterious effects on natural habitats and human health. Land use change for agriculture is the biggest threat to biodiversity globally.4 Somewhere between 21 and 37 percent of total global greenhouse gas emissions can be attributed to food systems, including agriculture and other land use, storage, transport, packaging, processing, retail, and consumption.5 Pollution from fertilizer and pesticide use runs off into rivers, lakes, and ultimately the ocean, threatening aquatic and marine ecosystems and the people who rely on those ecosystems for food, water, and jobs.6 Intensive agriculture has contributed to soil degradation, the spread of zoonotic diseases and antibiotic resistance, and the loss of traditional skills, knowledge, institutions, and farming practices.
The global food system feeds a world population of nearly 8 billion people, which is a remarkable accomplishment. Yet, more than 800 million people worldwide remain undernourished, nearly 150 million children are stunted (too short for their age), and nearly 50 million children are wasted (too thin for their height).7 At the same time, more than 2 billion adults and children are overweight or obese, in part because of a worldwide trend toward eating more processed foods and higher quantities of salt, sugar, and fat.8 Increasing rates of obesity have in turn boosted the number of diet-related chronic diseases, including diabetes, cardiovascular disease, and some kinds of cancers.
THE US-UK SCIENTIFIC FORUM ON SUSTAINABLE AGRICULTURE
It was against this backdrop that the National Academy of Sciences and the United Kingdom’s Royal Society convened leading scientists and practitioners in the fields of agricultural sciences, food policy, biodiversity, and environmental science (among others) at the US-UK Scientific Forum on Sustainable Agriculture, which was held in Washington, DC, on March 5–6, 2020. Participants at
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4 Tilman, D., M. Clark, D. R. Williams, K. Kimmel, S. Polasky, and C. Packer. 2017. Future threats to biodiversity and pathways to their prevention. Nature 546:73–81.
5 IPCC (Intergovernmental Panel on Climate Change). 2019. Climate Change and Land: An IPCC Special Report on Climate Change, Desertification, Land Degradation, Sustainable Land Management, Food Security, and Greenhouse Gas Fluxes in Terrestrial Ecosystems. P. R. Shukla, J. Skea, E. Calvo Buendia, V. Masson-Delmotte, H.-O. Pörtner, D. C. Roberts, P. Zhai, R. Slade, S. Connors, R. van Diemen, M. Ferrat, E. Haughey, S. Luz, S. Neogi, M. Pathak, J. Petzold, J. Portugal Pereira, P. Vyas, E. Huntley, K. Kissick, M. Belkacemi, and J. Malley, eds. Geneva, Switzerland: IPCC.
6 Onyango, J. 2018. Agricultural nutrients and pesticide pollution in aquatic ecosystems, with policy implications. Research & Reviews: Journal of Ecology and Environmental Sciences 6(4).
7 Development Initiatives. 2018. The 2018 Global Nutrition Report: Shining a Light to Spur Action on Nutrition. Bristol, UK: Development Initiatives.
8 The GBD 2015 Obesity Collaborators. 2017. Health effects of overweight and obesity in 195 countries over 25 years. The New England Journal of Medicine 377(1):13–27.
the forum included researchers who study a range of topics from soil health and crop sciences to food security and population health—communities that do not commonly have opportunities to collaborate. The US-UK Scientific Forums provide opportunities for leading scientists, primarily from the United States and the United Kingdom, to identify research opportunities, build multidisciplinary and international collaborations, and discuss how science can provide or inform solutions to pressing international problems.
Sessions at the forum were organized into four themes: enhancing food security in a rapidly changing climate, agriculture’s positive and negative effects on biodiversity and environmental health, agroecosystem productivity and agro-food system efficiency, and consumption behaviors, nutrition, and policy. This summary of the forum draws on three sources: the presentations by participants, the discussions following the presentations, and the plenary reports from small groups that met for 1 hour on the second day of the forum to discuss the future of sustainable agriculture. This summary should not be seen as representing conclusions of the National Academy of Sciences or the Royal Society. Rather, it consists of observations and suggestions for future action made by forum participants.
ORGANIZATION OF THE SUMMARY
Chapter 2 of this summary of the US-UK Scientific Forum on Sustainable Agriculture examines agriculture’s impacts on biodiversity and the environment. Agriculture is just one part of a much larger global food system, but it is the indispensable core of that system and inevitably shapes and modifies the system’s other components.
Chapter 3 considers the links among agriculture, diets, nutrition, and health. These links extend to the environment, because healthier diets tend to place less stress on the environment and biodiversity, which creates additional incentives and levers for change.
Chapter 4 looks at developments in science and technology that could enhance the sustainability of agriculture, including precision farming, biotechnologies, and research in the social sciences.
Finally, Chapter 5 discusses some of the policy actions that could move the world not only toward sustainable agriculture but also toward a much broader sustainable global food system.
