Raise food production 50% by 2030: UN chief

World food production must increase by 50 per cent by 2030 if it hopes to meet rising demand, the head of the UN told world leaders at a food summit in Rome Tuesday.

United Nations Secretary General Ban Ki-moon said countries must strive to reduce export restrictions and import tariffs in order to overcome the current crisis in global food costs and supplies.

' We have an historic opportunity to revitalize agriculture, especially in countries where productivity gains have been low in recent years," Ban told an audience that included about 60 heads of state, as well as scientists and activists.

Hosted by the UN Food and Agriculture Organization, the three-day summit in the Italian capital is aimed at finding ways to curb skyrocketing food prices, which have risen an average of 40 per cent worldwide since mid-2007 and 83 per cent in the last three years.

A combination of high oil prices, urbanization, the production of biofuels, flawed trade policies and other factors such as climate change have sent food prices soaring around the world, leading to riots and protests in places like Haiti and Egypt in recent months and major shortfalls amongst organizations that feed the hungry.

The rising cost of rice and other developing world staples has already led to export bans by India, Thailand, Vietnam and other major rice-producing countries.

Participants at the summit are being encouraged to establish a long-term plan for dealing with the crisis, which threatens to leave millions more malnourished around the world. An estimated 850 million people globally suffer from hunger, according to the FAO, most of them in developing countries.

In particular, the UN pointed to the devastating effects of years of agricultural and trade policies that have punished small farmers in developing countries. Compounding the problem are subsidies provided to farmers in rich nations such as Canada, which critics say unfairly disadvantage small farmers on the global market.

The viability of biofuels was also a major topic of discussion, with some arguing against the practice of diverting food crops toward fuel production.

"The head of the FAO, Jacques Dious, had harsh words for the developed world, asking questions such as why so much money is being spent on the development of biofuels when the same materials that are going into biofuels could feed the hungry," the CBC's Laura Lynch reported from Rome.

The United Nations in April set up a special, high-level task force to co-ordinate relief efforts, and many wealthy countries have announced big increases in food aid. In April, Canada pledged an extra $50 million to help the global food shortage this year.

But neither Prime Minister Stephen Harper nor any of his cabinet ministers are at the Rome summit to the chagrin of some participants.

"That's causing some disappointment from people here who say 'Look, Canada is the sort of country that grows enough food to take the edge off of the food crisis. It would be good to have a very prominent presence here,'" the CBC's Adrienne Arsenault reported from Rome.

While some participants have raised concerns about Canadian biofuel initiatives, others said Canada should be lauded for its recent food aid commitments, she said.

Meanwhile, Pope Benedict XVI on Tuesday decried hunger and malnutrition as "unacceptable" in a world equipped with the resources to feed more than it currently is.

In an address to summit participants, he urged countries to make "indispensable" structural changes to aid development.

Also in attendance at the summit was Iranian President Mahmoud Ahmadinejad, who on Monday reiterated his call for the destruction of Israel.

Equally controversial was an appearance by embattled Zimbabwean President Robert Mugabe. Both American and Australian diplomats refused outright to meet with former anti-colonial leader, whose land reform campaign has been accused of collapsing the country's agriculture sector.