Leaders of the G8 developed nations have pledged $20bn (£12bn) for efforts to boost food supplies to the hungry, on the final day of a summit in Italy.

G8发达国家峰会的领导人在最后一天的会议上已经承诺200亿美元用于扩大贫困地区的食品供应。

Many farmers in developing countries are at the mercy of drought or flooding

The investment, which is $5bn more than had been expected, will fund a three-year initiative（第一步，首创精神） to help poor nations develop their own agriculture.

US President Barack Obama said the issue of food security was of huge importance to all nations in the world.

Richer nations had a moral obligation to help poorer nations, he said.

Mr Obama added that the G8 nations had agreed to commit $15bn for the new initiative going into Friday's meeting, but had then promised an additional $5bn in "hard commitments" during the talks.

"We do not view this assistance（帮助，援助） as an end in itself," he said.

"We believe that the purpose of aid must be to create the conditions where it's no longer needed, to help people become self-sufficient, provide for their families and lift their standards of living."

Mr Obama, who has relatives in Kenya, said he had drawn¹ on his family's personal experience in his discussions with other world leaders.

The US will reportedly contribute some $3.5bn to the programme.

Mr Obama met representatives of Angola, Algeria, Nigeria and Senegal in L'Aquila, where the summit is being held. He will also meet Pope Benedict XVI in Rome before embarking² on an African tour later on Friday.

African leaders had earlier urged G8 nations to live up to past aid pledges.

BBC economics correspondent Andrew Walker says the idea is to put more emphasis on helping³ people feed themselves.

That is to be achieved with more investment in the agriculture of developing countries, and the G8 nations - Britain, Canada, France, Germany, Italy, Japan, Russia and the US - will provide significant resources, our correspondent adds.

However, although the total amount of overseas development aid (ODA) was increased in 2008, the rich countries are still behind on their target to double aid that was made at the G8 Gleneagles Summit in 2005 - and Italy is among the laggards⁴（落后者）. Not all the money pledged to the agriculture initiative at the summit will be new funding.

Kanaya Nwanze, president of the International Fund for Agricultural Development, told the BBC that he welcomed the announcement of more investment in agriculture in the developing world.

"It is time for us to switch because food security is not just food aid," he said.

"It is the ability of people to produce food locally and for them to be able to have access to local markets."

Ethiopian Prime Minister Meles Zenawi, who also attended Friday's talks, told Reuters news agency beforehand that the key message from African nations was that the G8 had to live up to its commitments.

Aid organisations have criticised some members for failing to deliver on the promise made at the 2005 G8 summit to increase annual aid levels to sub-Saharan Africa by $25bn by 2010.

Italy, the present summit host, has come under particular pressure for cutting, rather than increasing, aid this year.

Prime Minister Silvio Berlusconi has said the global economic crisis and Italy's mounting debts are responsible for a delay in Rome meeting its promises.

Climate challenge

On Thursday, when the summit focused on climate change, leaders from both developed and developing nations agreed that global temperatures should not rise more than 2C above 1900 levels.

That is the level above which, the UN says, the Earth's climate system would become dangerously unstable⁵.

Mr Obama said the G8 and developing nations had made important strides in dealing⁶ with climate change.

But the G8 failed to persuade the developing countries to accept targets of cutting emissions⁷ by 50% by 2050.

On Wednesday, the G8 agreed its own members would work towards 80% cuts by the same date.

UN Secretary General Ban Ki-moon said the G8 had not done enough and should also set 2020 targets for emissions cuts.

BBC environment analyst⁸ Roger Harrabin says the declaration is a significant step, with all big countries - rich and poor - agreeing there is a scientific limit on the amount we can warm the climate.

But there is still a huge way to go, he says, as developing nations like India will not sign up to any 2050 targets unless rich nations show more determination and offer more cash.