It sounds like a trivial sum — $110 (£72) per person, per year, for five years. But this is the amount required to lift each person in the Earth Institute's Millennium Initiative projects in Africa out of poverty, according to Jeffrey Sachs.

Professor Sachs promotes the use of official development aid, and lots of it, to tackle the core problems faced by Africa — disease, physical isolation, climate stress, environmental degradation and extreme poverty.

The Millennium Cities Initiative (MCI) and its rural counterpart, the Millennium Villages Initiative (MVI) are both designed to help regions in Africa to achieve the Millennium Development Goals (including the end of poverty and hunger; universal education; sex equality; combating HIV and Aids; environmental sustainability and improved maternal and child health) and increase economic growth through targeted investments.

Professor Sachs says: “Each of the cities has its own opportunities. Agriculture is obviously part of every one.” He also thinks that tourism has great potential and that there is also scope for businesses in light manufacturing, pharmaceuticals for the domestic market, minerals and mining.

The point of the MCI is to “exploit these opportunities” by bringing together public and private entities. His organisation hosts events where possible investors can meet and identify business potential so that they can “close the gaps in knowledge and get the markets to do a lot of the job”.

Professor Sachs argues that it is critical that economic aid is focused and targeted and that it engages the private, as well as the public, sector.

The MCI has been set up in nine cities in seven African countries — Mali, Malawi, Kenya, Nigeria, Senegal, Ethiopia and Ghana. The MVI has started in 79 villages in sub-Saharan Africa.

Critics of Professor Sachs argue that his approach is not borne out by the evidence. Countries that have received significant levels of aid in the past have experienced relatively stagnant growth. They add that his policies to tackle extreme poverty do not lead to the take-off that has been experienced in countries such as China and India, and neither do they address the problems of bad governance and corruption.

It is also argued that even if aid levels are increased, it is unlikely to be effective because the recipient countries are not in a position to absorb the extra income or use it in a productive manner.

With the global recession, this debate may become academic and the challenge will be to prevent aid falling from its current level rather than to convince governments to increase their contributions.

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