Food systems interact with, and affect, the environment in a great many ways beyond their greenhouse gas emissions. In order to feed humans, the global food system occupies over a third of the earth’s land surface; extracts large amounts of fish and animals from natural habitats; makes huge claims on natural resources; and dispurses various pollutants into the environment.
An appreciation of this wide range of environmental impacts is needed to understand why food systems are central to solving many of our biggest environmental problems, and ultimately to maintaining human well-being. Also useful, is to understand that the causes and solutions to these problems are often interconnected through food systems, resulting in trade-off situations where a course of action can at the same time, make one issue better and another worse.
This chapter provides an overview of the following:
- What types of environmental problem are connected to food systems?
- How do food systems cause these problems and what are their impacts?
- How have these impacts developed and what do future trends look like?
- How can changes in consumption help reduce environmental tradeoffs?
- Food systems impact on multiple interacting aspects of the environment including: water availability, water and soil quality, land use and land use change, GHG emissions, biodiversity, use of finite resources (e.g. phosphorus), and the aesthetics of the landscape.
- Together, impacts resulting from food systems affect the quality and the availability of a range of ecosystems services (including food supply), upon which the maintenance of human-well being and the viability of other life forms ultimately depends.
- Agriculture is the largest human use of water. The source and use of water by agriculture varies according to local context, as does the severity of any impacts depending on the degree to which water is available in a particular location.
- Water running off agricultural land can quickly carry fertilisers (nitrogen and phosphorus), pesticides, and sediment into natural water courses and lakes. There, excessive nutrient levels, toxicity, and sedimentation can lead to ecosystem disturbance, and to localised collapse.
- Agriculture is the largest human use of land and its expansion has come at the expense of the loss of biodiversity and natural ecosystems worldwide, via habitat destruction, degradation, and fragmentation.
- Ecosystems are strongly affected by agricultural practices, and in particular by intensification measures designed to increase outputs (e.g. yields), such as the application of pesticides and fertilisers, and more frequent disturbance of land.
- Biodiversity impacts must be considered at multiple spatial scales, because there is a tradeoff between the intensity of agricultural production, and the area of land needed to supply that food.
- Whether it is optimal to increase biodiversity locally on farmland (which generally requires less intensive practices), or to intensify production on existing land in order to spare biodiverse habitat elsewhere, is complex and often unclear.
- Food systems extract resources and species from natural ecosystems; especially from aquatic and freshwater environments where 85% of global fisheries are now fully exploited or are overfished. Ecosystems are degraded through changes in food webs and damage to habitat through destructive harvesting methods.
- To overcome limits to resource extraction from wild sources, the farming of aquatic species (aquaculture) has grown rapidly to meet growing demand. However, alongside this growth has arisen a new suite of linked environmental problems.
- Food loss and waste is a global problem which exacerbates all of the problems detailed above by requiring more agricultural production than would otherwise be necessary. It occurs at every stage of the food life cycle.
Tara Garnet, FCRN, University of Oxford
Jessica Finch, FCRN, University of Warwick;
Dave Little, University of Stirling;
Professor Tim Benton, University of Leeds;
Samuel Lee-Gammage, FCRN, University of Oxford;
Marie Persson, FCRN, University of Oxford;
Professor Mike Hamm, Michigan State University;
Dr Elin Röös, Swedish Agricultural University;
Dr Peter Scarborough, University of Oxford;
Dr Tim Hess, Cranfield University;
Professor Tim Key, University of Oxford;
Professor Tim Benton, University of Leeds;
Professor David Little, University of Stirling;
Professor Peter Smith, University of Aberdeen;
Mara Galeano Carraro.
Any inaccuracies and errors, remain the responsibility of the FCRN.
The production of this chapter was enabled by funding from the following sources:
The Daniel and Nina Carasso Foundation;
The Oxford Martin Programme on the Future of Food;
The Wellcome Trust;
The Esmée Fairbairn Foundation;
Waste Resources Action Programme (WRAP);
The Sustainable Consumption Institute at Manchester University.