GENEVA (AP) — World food production will have to increase by up to 100 percent by 2050 and focus on greener methods to sustain an expected 9 billion population, the U.N. said Tuesday in its annual survey of economic and social trends.

The U.N.'s annual World Economic and Social Survey called for governments to invest nearly $2 trillion (about 1.3 trillion euros) a year to help small-scale farming and to reduce environmental harm.

Only a fraction of the small investment goal has been reached so far through allocations from $20 billion in climate change funds managed by the World Bank aimed at helping developing countries boost clean energy technology, sustainable farming and other initiatives, the survey said.

The survey said the 2007-2008 food crisis and higher food prices "revealed deep structural problems in the global food system" that produce high carbon emissions and lead to a warmer climate, as well as more polluted land and water.

It also said 925 million people — more than one of every seven in the world — are undernourished and nearly all live in developing countries. Two-thirds are concentrated in seven countries: Bangladesh, China, Democratic Republic of Congo, Ethiopia, India, Indonesia and Pakistan.

Copyright 2011 The Associated Press.