Has Gleneagles failed to live up to its promises in Africa? Yes, says Jeffrey Sachs. No, says Bob Geldof

The American economist goes head to head with the Live Aid founder

Yes! Says Jeffrey Sachs

Basically Gleneagles failed. The promise to double aid to Africa by 2010 didn't materialise. Indeed the entire development effort has become terribly frayed, and real levels of assistance are in decline. Gleneagles is notable for its ambitions, but also for its failure to follow up. I don't attribute debt relief to Gleneagles – it was already under way several years before that. It targeted levels of overall development assistance and assistance for Africa.

As soon as those commitments were raised, I had responsibility in that area for the UN. I visited other countries that had no intention of following through. I heard very cynical things in the high reaches of government. In Germany, for example, senior officials said: "That's political, and not going to happen."

When the time came for the G8 to hold itself accountable, it didn't. The fact that its goals were not met was largely sidestepped in the review. Then came the financial crisis, and issues took a further back seat. With the notable exception of the UK, the G8 countries did not follow through. The US made some increases under George Bush, but under President Obama, it's mostly been treading water or reversing. Even things that should be absolutely simple, like a bold replacement for the highly successful Global Fund to fight Aids, TB, and Malaria, are proving difficult.

One of the ironies in all this is that, at the beginning of the last decade, claims were made that aid wouldn't work. Of course, what happened is that every place where investments were made – notably public health – there were tremendous achievements. That this record is not enough to propel the G8 is a discouraging fact.

"At this point, the G8 should be getting their own house in order for the benefit of the world. They should help G8 governments with their own budgets, which would help developing countries. What's central is that there's good governance by the G8 of G8 institutions. There is a specific line on cracking down on tax havens and massive tax evasion. Secrecy havens are highly destructive in the developing world. We will see if the G8 does anything real in cracking down on these abuses. The first place the G8 ought to work is in the financial system; it was the G8 financial system that nearly blew up the world economy. Wall Street and the City of London did a great deal of damage.

The G8 has not been an effective institution and I wonder if it should even exist any more given that we have the G20. If it followed through on commitments, I could see the value of it. If the G8 took on its own tax havens, of course, value could be proved. Powerful interests are blocking what is good for our countries; 2008 should have taught us strong lessons. But a lot of the immediate reforms haven't occurred.

All treasuries are short of funds, partly because major companies are shifting their profits to havens. It's quite discouraging. One could call it real politics, vested interest, or a lack of political will, but the results are not good.

Jeffrey David Sachs is an American economist and director of the Earth Institute at Columbia University

No! Says Bob Geldof

Kofi Annan said "Gleneagles was the Rubicon-crossing moment for Africa", and I think that's been true. Africa is now fully linked into the global economic wheel. It's got the fastest-growing middle class in the world; it's the fastest urbanising continent. Within seven years, it will have the youngest working population on the planet. Of the world's 10 fastest-growing economies, seven are African. Mortality rates are down, education levels have massively accelerated. All those things we said could happen have happened.

Jeff Sachs is a good guy and he knows that many figures counter what he is saying. Gleneagles did work. Debts were cancelled. Six months later, I was at the World Bank and IMF and they had to sign cheques. We had many lengthy and shouty meetings – one minister slapped me in the face – but we saw results very quickly. Tens of millions more children were going to school. And aid did increase – we met targets by 60 per cent and the UK went to 0.7 per cent.

It wasn't just Gleneagles: other things we couldn't have predicted came into play. There was massive Chinese investment and huge amounts of capital coming into the continent. Once you had debt forgiveness, then whatever money a country was making stayed in that country. Investment is stabilising the economy at a community level and supporting basic health infrastructure, education and agriculture.

None of that would have worked without the glue that held it all together: mobile telephony. The African labour and consumer market is accelerating. By 2040 at the latest, several African countries will be centres of the global and economic system.

This is all to the advantage of Britain – this government, as well as Blair and Brown – has done exactly what it said it would. They have been consistent and generous even faced with austerity. British private investment in Africa is 50 times that of Germany, and four times that of the US. People said we were naive, mad, a moral hazard – but it was nonsense. We're all dancing the debt forgiveness dance these days. There are huge problems still and massive amounts of poor people. But we're seeing beyond 7 per cent growth in some African countries.

Since 2005, we've known what works. By lifting people out of poverty, you gain – people can trade with you. They have cash. We need a world trade agreement. We need to agree Doha failed and find one fit for the new world. We need to deal with elements of hunger, like malnutrition. If a child is malnourished in its first three years, it loses 30 per cent of its cognitive ability for the rest of its life. We can stop that. We can stop poverty and it's entirely in our interest that we do. In 2005, half the world had to live on $2 a day. They couldn't – it was an asymmetric world and instability is inherent to asymmetry. How much better if that 50 per cent is productive? Countries don't go to war when they trade with each other; they need each other too much.

Gleneagles was without question the best G8 ever and it happened in this country. One phrase stands out: "Artists can never hope to change anything; the most they can do is remind those in power that not everyone agrees with them." While the G8 visits this country, it would be nice to remind those people who presided over some of the most disastrous financial decisions of our time that not everyone agrees with them.