By Bjørn Lomborg

In rich countries, the biggest causes of death are strokes, heart attacks and cancer, accounting for more than two-thirds of all deaths. But for the poorer world, people often assume that infectious diseases like diarrhea, tuberculosis, AIDS, malaria, measles and tetanus are the biggest killers. That is no longer true. While they are still substantial threats, broader availability of medication and vaccines along with higher living standards has caused such communicable diseases to drop dramatically to below 9 million deaths each year.

For the first time, more people in the developing world are now dying from strokes and heart attacks than infectious diseases. Combined, these so-called non-communicable diseases or NCDs cause almost two-thirds of all deaths in the developing world, about 23 million each year.

The good news is that there are tremendous ways to help, which could avoid up to five million deaths each year. Because the NCDs generally have received less attention, the solutions are often very effective and very cheap.

This is the argument made in a new paper written by Rachel Nugent of the University of Washington. It is part of a series commissioned by my think tank, the Copenhagen Consensus Center, from over 60 teams of top economists. The idea is to be able to compare the costs and benefits of a wide range of proposed targets to help the global community set the best targets for the next 15 years to follow the Millennium Development Goals. 193 national governments are now debating hundreds of proposed targets. In September, the world will agree to a list of targets to help build a better life for the world's poorest people. Our economic analyses show the world's leaders where they can help the most for each dollar spent.