Farming must feed more people more sustainably.
Advances in agricultural science and technology (S&T) have contributed to remarkable increases in food production since the mid-twentieth century. Global agriculture has grown 2.5-3 times over the last 50 years. 
This has let food production keep pace with human population growth so that, overall, there are enough calories produced per capita. However, progress toward reducing hunger is variable across the world (see figure 1).
Hunger and malnutrition affect every aspect of human development and persist for various reasons including unequal access to land, to sufficient and nutritious food, and to other productive resources.
Adequate food production is necessary but insufficient to ensure national nutritional security. In
Agricultural production needs to increase to address this unequal access to food and resources, and to meet the needs of a growing world population. It may need to increase by an estimated 70 per cent globally and by 100 per cent in developing countries by 2050 in order to keep pace with population growth and shifting diets.
Reformed agrifood systems will also need to navigate complex resource limits imposed, in part, by environmental degradation to which modern agriculture has contributed.
So the challenge for agriculture is three-fold: to increase agricultural production, especially of nutrient-rich foods, to do so in ways which reduce inequality, and to reverse and prevent resource degradation.
S&T can play a vital role in meeting these challenges - for example, by developing innovations that smallholders with limited resources can afford and use.
Land and water pressures
About 12 per cent (1.6 billion hectares) of the world's land area is used for agriculture. Land degradation, or the loss of land's productive capacity, is a global problem (figure 2), but especially in dryland regions, a quarter of which are devoted to agriculture.  Drylands also support over 30 per cent of the world's population. 
Water management is another major challenge. Agriculture accounts for 70 per cent of all water taken from aquifers, streams, rivers and lakes.  To meet projected demands, the efficiency of water use (crop produced 'per drop') will need to improve in both irrigated and rainfed zones.
Forty per cent of global increases in food production have come from irrigated areas. By 2050, the area under irrigation is projected to increase by six per cent over 2009 levels, and agricultural water withdrawals will need to increase by ten per cent over current levels. 
Rainfed systems are the world's largest agricultural system, taking up 80 per cent of cultivated land area and producing 60 per cent of the world's crops. In
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