1.3 What are the relationships among food systems and environmental change?

1.3.1 Food system interactions with the environment

Source: FCRN. See side-panel for references

The food system as a whole – including agricultural production and agriculturally induced land-use change, transport, storage and food preparation – contributes around 20-30% of global human-made greenhouse gas emissions. See Chapter 2 for more on how these impacts can be quantified, and Chapter 3 for more on the greenhouse gas emissions from food systems.

Food systems are also important causes of rising scarcity, species loss and land degradation. A substantial amount of the food produced is lost or wasted along the supply chain, causing significant problems. See Chapter 5 for more on these topics.

1.3.2 Food systems as a major source of climate changing greenhouse gas (GHG) emissions

Global perspective – food systems contribute about 20-30% of GHGs.

Based on Vermeulen, S.J., Campbell, B.M. and Ingram, J.S.I. (2012)

The food system is estimated to contribute approximately 20-30% of global human-made GHGs although there is huge inherent uncertainty in these estimates.

The major impacts come from farming/agriculture and land-use change (see the previous slide), with fertilisers, pesticides, manure, farming and land-use change together contributing as much as around 24% of global GHGs. Livestock alone contribute 14.5% of human-made GHG emissions

Stages later in the food system such as packaging, retail, transport, processing, food preparation and waste disposal combined contribute around 5-10% of global GHGs although their importance and likely impacts are set to grow.

These stages are discussed in more detail later in this chapter.

Within food systems, consumption patterns and production are interrelated, both impacting on one another. These topics are discussed more in Chapter 4.

1.3.3 Food systems as a cause of other environmental problems

Biodiversity loss from agricultural production and expansion.

NEAA (2010)

Without action, increased demand for food, and in particular for resource-intensive food such as meat, will lead to significant and continued biodiversity losses. This would primarily arise from agricultural expansion into new areas to grow crops (often to feed livestock), from the creation of new pasture lands, and encroachment on and fragmentation of ecosystems. Note that a degree of uncertainty exists around population growth, demand for food, and how food production responds to these changes. For discussions about expected population change, see later in this chapter and Chapter 4 and Chapter 7.

These biodiversity losses could be modified or reduced by increasing the extent of protected areas, through yield increases in food production, better forest management, by actions to moderate demand for resource-intensive food consumption and to reduce waste, and by limiting climate change. Some of these mitigation options are explored in Chapter 4, in relation to addressing greenhouse gas emissions.

Fish stocks are under increasing pressure

WWF (2015).


The last 50 years have seen dramatic reductions in wild fish stocks, due mainly to over-fishing and destructive fishing techniques by humans. Around 85% of fisheries are now fully exploited or overfished, with 29% of marine fisheries being overfished. Marine vertebrate populations declined 49% between 1970 and 2012.

Fish are an important food source however, and nearly 3 billion people rely on fish as a major source of protein. Fisheries therefore need to be protected on grounds of ‘self interest’ – to safeguard global food security – as well as for intrinsic environmental reasons.

Other environmental damage to marine ecosystems includes the increase in oxygen-depleted dead zones resulting from nutrient run-off from agriculture, loss of coral ecosystems and mangrove systems. Some of the mangrove loss is a consequence of aquaculture / seafood farming although the influences are diverse and changing. See later in this chapter for more on aquaculture.

Only 3.4% of the oceans are protected.

Certification of sustainable fisheries does exist, although coverage is not high and illegal fishing continues.

1.3.4 Climate change influences on food supply, availability and quality

There are also huge uncertainties in how climate change will impact future food productivity.

Much depends on the interplay between temperature increase, increased CO2 effects on plant growth, extreme events (drought, flooding) and water supply and use. We also need to consider climate change impacts on economic development, trade, transport and logistics infrastructure, population migration, food prices and much more.

Easterling, W.E. et al. (2007) 

A gradual warming may benefit Northern countries initially, by expanding the range of crops that can be grown and lengthening growing seasons, but beyond 2050 the negative impacts of climate change are likely to outweigh any benefits. The impacts on Southern (poor) countries are already starting to hit home and to be negative, and the impacts are predicted to worsen over time. Poor people in poor countries who are less able to adapt and who are already vulnerable in multiple social and economic ways, will likely suffer most.