Baroness Amos, head of UN humanitarian affairs, appealed on Tuesday for donors to "dig deep" to help the 10 million people affected by the worst drought conditions in 60 years in east Africa.
Last year, the UN appealed for $500m (£310m) for Ethiopia, Somalia and Kenya to address food insecurity, but only half has been funded, while a $30m appeal for Djibouti has reached just 30% of the target. A lack of seasonal rains has led to failed harvests, acute water and pasture shortages, and the deaths of thousands of animals in the region. Thousands of people have already left their homes in search of water and grass for their livestock.
In some areas of Somalia and northern Kenya up to 30% of the population is suffering from acute malnutrition, which is double the amount sufficient to declare a humanitarian emergency.
On Monday, Oxfam launched its biggest appeal, seeking £50m to help 3 million people, and on Sunday the UK's Department for International Development announced £38m in emergency food aid for Ethiopia.
"We are appealing for donors to dig deep," Amos told the Guardian. "The scale of the problem is much greater than we had anticipated last year. We need the money very quickly as children and some adults are turning up in refugee camps malnourished. We launched an appeal for this year at the end of last year, but the impact has been much greater. In Somalia, the number of people affected has gone from 2 million to 2.5 million because of a convergence of factors including drought, cereal prices and conflict."
Up to 1,000 Somalis a day are crossing the Kenyan border to Dadaab, already the world's largest refugee settlement with 367,000 residents.
Amos stressed the importance of finding long-term solutions to avoid lurching from one crisis to another. The area has experienced severe drought and food shortages on a regular basis since the 1980s. Recent appeals for funds were made in 2006, 2008 and 2009.
"We need a longer-term strategy that builds on economic development and sustainable livelihoods," said Amos, adding that work had to be done at national and regional levels.
Amos now chairs a UN interagency standing committee to monitor the progress – or lack of progress – in terms of fulfilling pledges made two years ago by the world's eight largest economies.
The G8, meeting in L'Aquila, Italy, pledged $22bn towards agriculture in the developing world to boost food self-sufficency and food security. They agreed that investment in small farms in Africa was the key to avoiding a food crisis, but groups such as ActionAid say there is little evidence that aid for agriculture has risen significantly as a result of the pledge.
"We have fallen behind in some areas," said Amos. "There is a need for more dynamism in the process, but there are so many different people involved, so many reasons for lack of progress. It is not just about drought, there is the impact of climate change, governance is weak in some of these countries ... It's a vast geographical area, all of this makes it a very complicated picture."
Jamie Drummond, executive director of the advocacy group, ONE, said the current emergency should not obscure the progress that has been made elsewhere in Africa, symbolised by a rising African middle class. Like Amos, he urged rich countries to fulfil the pledges made at L'Aquila.
"This is not yet a famine of biblical proportions," he said. "It's a bad situation that can be avoided for a few hundred millions of dollars. We have to ensure the money gets through quickly, and let's keep previous promises so we can avoid similar situations."
ONE is due to release a report on where the G8 is falling down on its pledges.
