The 85 richest could make a transformative contribution

From Prof Jeffrey D Sachs.

Sir, Deirdre McCloskey (" Equality is irrelevant if the poor are growing richer ", August 12) seeks to absolve the world's super-rich of responsibility for the world's poor, but she botches the maths. A correct calculation shows that just the 85 wealthiest people in the world could indeed make a major contribution to ending the massive suffering of the world's poorest.

The top 85 people have a combined net worth of $2tn according to the most recent Forbes survey. Assume, as she does, that these assets are all put to work for the world's poor. With a standard real payout of 5 per cent per year, as with the endowment of a foundation or university, the annual flow is $100bn.

As of 2015, around 1bn people (the so-called bottom billion) will live in extreme poverty using the World Bank's standard definition. With around five people per household, this means around 200m households below the poverty line. The wealth of the 85 billionaires would thereby enable a flow of $500 per poor household per year.

Such a sum would be completely transformative, as shown by multiple studies of the UN Millennium Project, World Health Organisation, Global Fund to Fight Aids, TB, and Malaria, Global Agriculture and Food Security Program, and other organisations. Such a sum would fully close the funding gap of the fight against Aids, TB, malaria; finance all basic vaccinations for poor children; enable the training and deployment of at least 1m community health workers in Africa; enable all impoverished smallholders to finance improved seed and nutrient inputs; guarantee universal access to micro-grid electricity; and much more. In short, the funds would not only enable the poorest households to stay alive - saving millions of lives per year - but also to make the transition over several years from subsistence to commercial farming and other livelihoods above the poverty line, enabling a long-term escape from poverty.

Ms McCloskey makes at least two blunders. First, she divides not by the number of extreme poor but by a much larger population. Second, she fails to understand that for the poorest of the poor, a little bit of targeted investment can go very far in fighting disease, poverty, illiteracy, and lack of access to basic infrastructure, as has been evident for example in the sizeable reduction of child mortality in impoverished countries in recent years.

Jeffrey D Sachs,

Director, Earth Institute,

Columbia University,

New York, NY, US