G8 leaders yesterday pledged $20bn in farm aid to help poor nations feed themselves, surpassing expectations on the final day of a summit that has yielded little progress on climate change and trade.

G8 leaders yesterday pledged $20bn in farm aid to help poor nations feed themselves, surpassing expectations on the final day of a summit that has yielded little progress on climate change and trade.

The United States used the meeting of world leaders to push for a shift towards farm investment from food aid, and it will make $3.5bn available to the three-year programme.

"There is no reason Africa should not be self-sufficient when it comes to food," said President Barack Obama, pointing out that his relatives in Kenya live "in villages where hunger is real", though they themselves are not going hungry.

Mr Obama said Africa had enough arable land but lacked seeds, irrigation and mechanisms for farmers to get a fair price for their produce - issues that the Group of Eight richest nations, emerging powers and African countries promised to tackle.

But Africa told the wealthy powers they needed to honour past commitments, mindful that some G8 countries had fallen short of their 2005 promise to hike annual aid by $50bn by 2010, half of which was meant for Africa.

The United Nations says the number of malnourished people has risen in the past two years and is expected to top 1.02 billion this year, reversing decades of declines. The global recession is expected to make 103 million more people go hungry.

Aid bodies such as the World Food Programme said a last-minute surge of generosity at the summit in Italy's L'Aquila resulting in the $20bn pledge was "greeted with great happiness".

With African leaders from Algeria, Angola, Egypt, Ethiopia, Libya, Nigeria, Senegal and South Africa meeting G8 leaders, the focus on agricultural investments reflects a US-led shift away from emergency assistance towards longer-term strategies.

Senegal's President Abdoulaye Wade said that Obama, who will make his first visit to Africa as US president after the G8 summit, brought a welcome new focus on African farming.

"The United States produces maize and some crops and sends it to people in famine, but the new conception is to produce these crops in Africa and not in the United States," Wade said.

The $20bn over three years may compare unfavourably with the $13.4bn the G8 says it has already disbursed between January 2008 and July 2009, but aid groups said the funds pledged yesterday were more clearly focused.

Japan and the European Union were also championing a code of conduct for responsible investment in the face of growing farmland acquisition or "land grabs" in emerging nations.

The L'Aquila summit has produced chequered results on other issues, making only limited progress in crucial climate talks following the refusal by major developing nations to sign up to the goal of halving world greenhouse gas emissions by 2050.

The 17 biggest emitters in the Major Economies Forum chaired by Obama failed to get emerging powerhouses such as China and India to agree to these targets, though they did all agree temperature rises should be limited to two degrees Celsius (3.6 Fahrenheit).

But Mr Obama, also suffering a delay to his own global warming bill in the US Congress, said the talks had created momentum for a new UN climate change pact in Copenhagen in December.

G8 leaders said the global financial crisis still posed serious risks to the world economy. Further stimulus packages for growth might still be required and it was dangerous to implement "exit strategies" from emergency measures too early.

"Reaching the bottom of the slump is not when you start with exit strategies. We need to choose a point where we've already got some way out of the trough," German Chancellor Angela Merkel said.

She dismissed a Chinese proposal, aired at the summit, for debate on seeking an alternative global reserve currency to the dollar in the long term as something that was not of "practical relevance" for the time being.

There also appeared to be growing consensus at the summit that the G8 itself, long criticised as an elite club, no longer reflected the shifting patterns of global economic power.

Under Italy's presidency, the G8 (the United States, Japan, Germany, France, Britain, Italy, Russia and Canada) expanded to a "G14" with major emerging powers on the second day, and added about 15 more, including nine African countries, on the final day.