The theme of this year's UN World Water Day is water and food security. Agriculture is by far the main user of freshwater. Unless global capacity is increased to use water wisely in agriculture, the world will fail to end hunger and will open the door to a range of other ills, including drought, famine and political instability. In many parts of the world, water scarcity is increasing and rates of growth in agricultural production have been slowing. At the same time, climate change is exacerbating risk and unpredictability for farmers, especially for poor farmers in low-income countries who are the most vulnerable and the least able to adapt.