If we want winners, there will be losers

The world cannot afford to tackle all its dire problems, so we are going to have to make some tough decisions, says Bjorn Lomborg

Nobody wants to be the bad guy. Nobody wants to say that one undeniably important global problem such as climate change should get less attention than another such as HIV/Aids. Yet when it came down to it, there was a marked degree of agreement among the UN ambassadors brought together by the Copenhagen Consensus - measures to tackle financial instability, conflict and climate change were low priorities compared with the need to deal with communicable diseases, sanitation and water, education and malnutrition.

The Copenhagen Consensus asked eight UN ambassadors how the international community should spend an additional $50 billion (£ billion) on new initiatives to reduce global suffering. These representatives of nations including the US, China, India and Tanzania discussed and ranked in order of priority 40 solutions to ten of the most pressing challenges currently facing humanity.

Over two days, a few weeks ago, the decision-makers heard from a succession of specialist economists and UN experts arguing that their particular solutions to particular problems should be better funded - an increased malaria effort, for example, or wider distribution of condoms. Following this academic competition, the ambassadors had to consider the likely cost and benefit of each course of action in comparison with the rest. Then came the hard bit - they had to decide not only what to make the top priority but also what to put at the bottom.

When the Copenhagen Consensus first did this exercise two years ago with eight of the world's top economists, even respected Nobel laureates became squeamish about announcing the lowest priorities. I get that twinge too. In a perfect world, we should support everything. We should combat climate change, stop communicable disease, give everybody clean drinking water, end war. I would love to live in that world. Nobody does, of course.

Yet we rarely have the intellectual discipline to admit that if we spend more money here, it means less money to spend there. Most people agree that rich nations owe the rest of the world something. But with so many challenges, which projects should be funded? Some, such as Jeff Sachs, director of the Earth Institute at Columbia University, strongly believe that we should try to do everything. We should not predominantly be prioritising. But to me that is untenable. We would end up doing a little for every problem when it is smarter to do more of some and less of others. We have to be honest and admit that we are confronted with a trade-off.

On the face of it, it is difficult to compare removing a tonne of carbon from the atmosphere with a reduction of the incidence of HIV/Aids. But economics can help us make a more informed choice, because it can give us an estimate of the costs and downstream benefits. In essence, with a smart focus on prevention of HIV, every dollar spent will end up doing about 40 dollars' worth of social good - a very positive outcome. Likewise, removing carbon also does good, but at a high price. At the 2004 meeting, the economists estimated that for each dollar spent, we would end up doing somewhere between 2 and 25 cents' worth of good.

The ambassadors drew on the economists' analysis and the prices they had calculated, but also added their own political criteria to prioritising action, having listened to pitches from competing experts.

The rough rankings ultimately produced were significant but not definitive. They will provide extra ammunition for the people who argue for the top priorities and put bigger obstacles in the way of those defending the bottom priorities. It could mean a little more money goes to the best performing causes. Certainly, Copenhagen Consensus priorities have already been quoted in the World Bank's new position document on malnutrition; have helped persuade the Danish Government to increase funding to prevent the transmission of HIV/Aids; and have influenced the US decision to provide $1.2 billion towards tackling malaria.

The main point, however, is to demonstrate that we cannot avoid making such choices. We cannot ignore this responsibility. People have to think about these problems in a more fundamental way, talk about priorities and make some tough decisions. This maximises the overall benefits. And even the losers could benefit in the end, their advocates forced to sharpen up and find ways to make investing in their fields a smarter choice for the policymakers.

Former US Vice-President Al Gore tells us with passion about the "inconvenient truth" of global warming. I would like to see the other challenges facing humanity defended by similarly great advocates. There are many "inconvenient truths". We need to acknowledge the necessity for priorities and so we need many more Gores, each arguing different and important causes. The Copenhagen Consensus can play an important role in encouraging this. The initiative will not make the world right, but it will hopefully make it slightly less wrong.

Bjørn Lomborg is director of the Copenhagen Consensus Centre. He is editor of How to Spend $50 Billion to Make the World a Better Place , Cambridge University Press, £9.99.