To produce two steaks you need 15 000 liters of water.Each American uses 7,500 litres of water per day—mostly for food. One litre of water is needed to irrigate one calorie food. Inefficient water use can mean 100 litres are used to produce one calorie. Irrigation takes up to 90% of water withdrawn in some developing countries. Globally, agriculture is the largest user of water, accounting for 70% of total withdrawal.
By 2050, agriculture will need to produce 60% more food globally, and 100% more in developing countries.
Economic growth and individual wealth are shifting diets from predominantly starch-based to meat and dairy, which require more water. Producing 1 kilo rice, for example, requires about 3,500 litres of water, while 1 kilo of beef some 15,000 litres. This shift in diet is the greatest to impact on water consumption over the past 30 years, and is likely to continue well into the middle of the twenty-first century.
The current growth rates of agricultural demands on the world’s freshwater resources are unsustainable. Inefficient use of water for crop production depletes aquifers, reduces river flows, degrades wildlife habitats, and has caused salinization of 20% of the global irrigated land area. To increase efficiency in the use of water, agriculture can reduce water losses and, most importantly, increase crop productivity with respect to water.
With increased intensive agriculture, water pollution may worsen. Experience from high income countries shows that a combination of incentives, including more stringent regulation, enforcement and well-targeted subsidies, can help reduce water pollution.
Water World Day 2015: Water is food