The world is headed "down a dangerous path" with disruption of the food system possible within a decade as climate change undermines nations' ability to feed themselves, according to a senior World Bank official.

Sydney, 27 August 2014. Rising urban populations are contributing to expanded demand for meat, adding to nutrition shortages for the world's poor. Increased greenhouse gas emissions from livestock as well as land clearing will make farming more marginal in many regions, especially in developing nations, said Rachel Kyte, World Bank Group Vice President and special envoy for climate change.

"The challenges from waste to warming, spurred on by a growing population with a rising middle-class hunger for meat, are leading us down a dangerous path," Professor Kyte told the Crawford Fund 2014 annual conference in Canberra on Wednesday.

"Unless we chart a new course, we will find ourselves staring volatility and disruption in the food system in the face, not in 2050, not in 2040, but potentially within the next decade," she said, according to her prepared speech.

Agriculture and land-use change account for about 30 per cent of the greenhouse gas emissions blamed for global warming. Feed quality can be so low in arid parts of Africa, where livestock typically graze on marginal land and crop residues, that every kilo of protein produced can contribute the equivalent of one tonne of carbon dioxide - or 100 times more than in developed nations, Professor Kyte said.

A two-degree warmer world - which may occur by the 2030s on current emissions trajectories - could cut cereal yields by one-fifth globally and by one-half in Africa, she said.

The river deltas of Asia, which provide almost two-thirds of the world's rice, will become more vulnerable to sea-level rise and storm surges. By 2050, each hectare of paddy will have to feed 43 people, up from about 27 now, according to a report carried by China Daily.

Professor Kyte said the focus has to turn to so-called "climate-smart agriculture", which contributes to increased productivity of crops, less wastage and a smaller climate change impact.

Read more about climate-smart agriculture and the full article by Peter Hannam here.