Food systems not only depend on nature, but also exert important pressures on it. For example, agriculture uses half of the world’s ice-free land surface – far more than any other human activity and considerably greater than urban land use and other infrastructure, which only accounts for 1%. Agriculture is also responsible for about 70% of global water use. Including all other stages between farm and fork, food systems are responsible for 21-37% of global greenhouse gas emissions. Food systems are also implicated in deforestation, overfishing, water pollution, and several other environmental concerns. Much of the environmental footprint of food systems occurs at the primary production stage. For example, farming and associated land use changes account for most of the greenhouse gas emissions related to food systems.
Broadly speaking, greater food production can come from three sources, with starkly different environmental implications: greater land use, greater use of other inputs, and greater efficiency in how these inputs are used. Historically, most of the increase in food production came from increased agricultural land use, as growing populations expanded the global area under crops and the area used for grazing animals. This in turn led to large-scale loss of forests and other natural landscapes. However, since 1960, food production more than tripled while land use grew by only 10%-15%. This partial “decoupling” of food production and land use occurred in two stages. From the 1960s to the 1980s, global agriculture mostly relied on greater use of other inputs such as fertilisers, improved seeds, irrigation water, and pesticides to expand output. However, over time efficiency gains (e.g. due to better management practices or improved genetics) gained in importance, and since the 1990s such efficiency gains have been the major factor driving the growth of global agricultural production.
These three ways of expanding food production – greater land use, greater use of other inputs, and greater efficiency – have very different effects on the environment. Expansion of agricultural land is associated with important greenhouse gas emissions, threats to biodiversity, and loss of soil carbon. Increased use of inputs is associated with its own set of environmental problems: for example, the widespread use of synthetic nitrogen fertiliser not only contributes to greenhouse gas emissions but can also cause severe damage to aquatic ecosystems. However, context matters in the use of inputs and their impacts. Over the past two decades, OECD countries have on average experienced declining nitrogen and phosphorus surpluses despite growing agricultural production. As another example, while global agriculture is responsible for 70% of freshwater withdrawals, water stress varies around the world. Some regions of the world face more water scarcity than others, and even in water-abundant countries there can be local “hotspots” with water scarcity risk.
In contrast with expanding land and input use, efficiency gains make it possible to produce more food without increasing the environmental footprint of food systems. For this reason, innovation can have important benefits in terms of both productivity and sustainability.
Better policies can make a big difference for the environmental performance of food systems. Unfortunately, many agricultural policies around the world often harm the environment, stifle innovation, and reduce productivity growth. Moreover, existing policies contribute little to building resilience in food systems and in many cases undermine it, for example by for example by not pricing agricultural water use correctly. Similarly, fisheries policies often subsidise fuel or the construction of new vessels, thus stimulating overfishing. Better policies can thus greatly improve the environmental footprint of agriculture, including by enhancing climate mitigation.
A wide range of OECD data and analysis can inform the design of policies to improve the environmental performance of food systems.