Obama's America: One in Five Americans Go Hungry while Food Waste Increases
Food waste in the US, China and India alone can yield food for more than 400 million people.

Meeting the basic food needs of three billion more people without increasing agriculture's environmental footprint is possible if nations, foundations, businesses and citizens adopt a few food-security efforts.

The report in Science sees biggest opportunities in this for China, India, US, Brazil, Indonesia and Pakistan, along with Europe.

In a three-pronged approach it advocates producing more on existing land; growing crops more efficiently and using them efficiently.

Worldwide, 60% of nitrogen and nearly 50% of phosphorus applications exceed what crops need, the report says. China, India and the US -- and three crops, rice, wheat and corn -- are the biggest sources of excess nutrient use worldwide.

Rice and wheat are also the crops that need most water and India, Pakistan, China and the US account for the bulk of irrigation water use in water-limited areas. Boosting crop water use efficiency can reduce water demand 8 to 15% without compromising food production.

Agriculture is responsible for 20 to 35% of global greenhouse gas emissions, in the form of carbon dioxide from tropical deforestation, methane from livestock and rice growing, and nitrous oxide from crop fertilisation.

By using fertilisers and water efficiently, there are big opportunities to reduce greenhouse gas production. In Brazil and Indonesia greenhouse gas production comes from deforestation; China and India from rice production; and China, India and the United States from crop fertilisation.

Food waste in the US, China and India alone can yield food for more than 400 million people.

Without expanding farm land but focussing on the existing one, the gap between potential and actual yield can be bridged to provide enough calories to feed 850 million people.