And they say food security problems will only grow as the population increases and the climate changes.

　　In a new report ahead of this summer’s Rio +20 U.N. Sustainable Development Conference, the experts deliver a roadmap for feeding the world on a warming planet.

　　The new report, by a commission of experts from 13 countries, highlights the tangle of contradictions in today’s global food situation.

　　“We have a billion people on the planet who are food insecure and a billion who are suffering from over-nutrition. We have possibly as many as a couple of billion more who are malnourished,” says Molly Jahn, a member of the Commission on Sustainable Agriculture and Climate Change and an agronomist at the University of Wisconsin at Madison.

　　At the same time, she says, a third of the food produced for human consumption is wasted.

　　Meanwhile, agricultural production is a major contributor to climate change, which produces more frequent crop-destroying weather extremes.

　　With another 2 billion mouths to feed by 2050, and an increasingly wealthy world eating higher on the food chain, the commission says pressure on the food system threatens to push past what the planet can sustain.

　　Food-secure by 2050

　　Jahn says the report outlines a set of solutions to reach a food-secure world by mid-century that involves actions at all levels, “from very small-scale local action that will involve getting more and better quality food from the same or smaller patches of ground, to global outcomes that have to do with the way we manage, for example, trade of commodities.”

　　The report recommends boosting the productivity of small-scale farmers to increase food supplies and reduce poverty.

　　But productivity must increase without doing further damage to an already strained environment, it says. That means growing more food without clearing more forests or over-using chemical fertilizers, both of which contribute to climate change.

　　It also says the need for food can be reduced by cutting food waste and promoting healthier diets with less meat.

　　The report is punctuated with case studies highlighting successes for each recommendation, from Bangladesh to Brazil.

　　Making the recommendations a reality will require a much greater commitment from everyone from policymakers to the private sector, the report adds, and a much bigger global investment in sustainable agriculture.