Food is fundamental for human existence and health but many of the world’s inhabitants experience ongoing hunger. For some this is due to drought, others war and for many it is a lack of money to buy food. The United Nations, Food and Agriculture Organization estimates that 850 million people worldwide are hungry and a greater number suffer from nutrient deficiencies. Approximately one billion people have inadequate nutrient intake, others excessive calorie intake. Obesity has become an epidemic in developed countries, while in some developing societies the double burden of nutrient deficiency and obesity is apparent. The challenge of preventing hunger and malnutrition will become even greater as the global population grows from the current 7 billion people to nearly 10 billion by 2050.

Not only is the global population increasing, we are living longer and becoming more affluent. As incomes increase, diets become more energy-dense and meat becomes a larger proportion of the diet. These changes in population and cuisine have led to a tremendous rise in the demand for animal-source protein. The competition between livestock and humans for grains and other high quality plant foods, whether real or perceived, is recognised as a major challenge. This has become more complicated with the diversion of grain to the production of biofuel.

For many years there has been an ongoing debate about the benefit or otherwise of animal-source foods, especially red meat consumption. In the past, claims of the detrimental effect of animal-sourced foods on human health have been made without rigorous scientific investigation. There is no doubt, however, that animal source foods, including lean meat, fish, poultry, eggs and milk, are an excellent source of protein and micronutrients. Fish can be added to this list but wild fisheries are rapidly being depleted. It should not be forgotten that humans evolved as ‘meat eaters’. It is unlikely that we will lose our appetite for meat but we must curb it. In many instances, the mechanism that allows impoverished families to improve their income and wellbeing is access to livestock or poultry.

Whatever diet we choose in the future our food will need to be produced more efficiently. Increased agricultural productivity must come from a reduced land area and resource base. Arable land continues to be lost due to soil degradation and urbanisation. We will need to be less dependent on resources that are becoming scarce, like arable land and water, or more costly, like energy and petrochemical-based inputs, including fertilizers. Some would argue that it is how we manage the nexus between food, water and energy that is our biggest challenge for global food security.

Conversely, the environmental impact of agriculture should not be forgotten. There is no doubt that agriculture exerts considerable pressure on water supplies, especially when irrigation is used. What form of energy will agriculture use in the future to produce, process and transport our food? The impact of agriculture on plant and animal biodiversity and other ecosystem services also must be addressed. Pollination of crops by bees is an integral component of agricultural production. Any disruption to this ecosystem service could have devastating consequences for food production.

Climate change will accentuate the challenges identified above. Pest and disease problems of plants and animals are likely to increase partly in response to climate change. Consensus exists regarding impacts of agricultural production, processing and distribution of food on global climate change. A significant proportion of anthropogenic emissions of greenhouse gasses come from agriculture and these emissions need to be reduced.

Just as the climate system is global, so is our food system. While globalisation may create opportunities and increase food distribution the benefits predominantly flow to those with a developed and secure food supply. Government subsidies, import restrictions and food safety legislation all mitigate against an equitable distribution and pricing of food. In some situations this will lead to civil unrest.