There has recently been a lot of focus on methane, as it is an important contributor to climate change. The food system is one of the largest emitters of methane, and the gas is particularly associated with ruminant livestock (cattle, sheep and goats) and with rice production. Despite its significance as a greenhouse gas, there is also considerable confusion over how we should quantify the climate impacts of methane emissions. This is because there are important differences in how methane and carbon dioxide – the major human-generated greenhouse gas – affect the climate. This explainer provides an overview of the key points about methane, and addresses some common areas of confusion. Last update: 11 June, 2019 https://www.doi.org/10.56661/0f7f7b1e

How food gets to our plates and what happens afterwards, connects many issues of concern, including health, biodiversity, climate change, livelihoods, and more. This chapter, and associated resources, provides an entry point into ‘food systems’ thinking and the multifaceted set of issues that are connected through food. It provides a foundation for the wider set of ideas and complexities that are explored in the other chapters of Foodsource.

Food systems use large amounts of natural resources and have significant environmental impacts; so what can we do to make them more sustainable? This chapter provides an accessible primer on the life cycle assessment (LCA) methodology

Emissions resulting from the many activities involved in food systems, account for a substantial portion of all human-caused greenhouse gas (GHG) emissions and, as such, contribute to climate change. A major challenge for the sustainability of food systems is, therefore to figure out how its contribution to GHGs can be reduced. If we are to be able to address and mitigate food systems’ contributions to climate change, it is important to understand where and how the greenhouse gas emissions arise across the whole food system. Also important, is to understand how different ways of organising parts of the food system, can result in differing levels of greenhouse gas emissions.

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.

Food systems are central to human well-being. We rely on them for nourishment, employment, livelihoods, culture and more. Reliable access to sufficient food is a foundation of human health, and of social and political stability. While the impacts of food systems on the environment are great, changes to the climate and the wider environment — to which food systems contribute — also have major implications for the functioning of food systems and all that they support. Understanding this matters, because sustainable food systems in the future must not only maintain human well-being with fewer environmental impacts, but must also be able to cope to different environmental conditions to those experienced today.

It is an internationally agreed objective to cut human-caused greenhouse gas emissions to zero this century, to avoid the worst impacts of climate change. Given the major contribution of food system activities to total human-caused emissions, reducing these emissions is of great importance. But how and by how much can emissions be reduced, while also feeding a growing population? There are different perspectives on how food systems emissions can be reduced and it is helpful to explore these since these differences also underpin many other debates around food system sustainability. Understanding these perspectives helps to put specific proposals for reducing food system emissions into a wider food systems context.

Today, billions are malnourished: not eating a diet containing energy and nutrients in healthy amounts. Both lack of food and excess of consumption cause huge levels of disease worldwide. To a significant extent, the food systems in which people participate determine what people can and do eat (i.e. their diets); and as a consequence, their health. Food systems are, therefore, central to solving many of the world’s biggest health challenges. But the way in which they affect health in different regions and among different groups of people is complex, and varies greatly. An understanding of these interconnections and their effects is needed, in order for food systems to be changed in ways that promote human wellbeing.