Bono has challenged the governments of the richest countries to deliver on their promises to fight poverty and disease in the poorest countries.
Speaking to political and business leaders at the World Economic Forum in Davos, he said he remained optimistic that the rich world would deliver on its 2005 commitments to cancel the debts of poor countries and double aid to African countries by 2010.
"There were some serious promises made," he said. "The cheques were signed but as you know, politicians like signing cheques but they don't like cashing them.
"Two years on, it's time to take the temperature. If those promises are not kept ... it will make a generation of cynics. I don't believe that's going to happen, I am optimistic we're going to get through this."
He said debt cancellation was already responsible for 20 million African children going to school but there was still "lots, lots, lots to do."
The G8 meeting this year will be hosted by Germany. Bono, along with British Prime Minister Tony Blair, told reporters that investing in fighting poverty in Africa remained a priority.
``As we go into Germany, this is where we find out if we are making progress, and if we fail it is corruption of the highest order, in my opinion.
"Africa is this magical, extraordinary continent and we've got to start describing it more as an opportunity than a burden."
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