This is a column about how good intentions can run amok. It tells the story of how an honourable, intelligent man set out to avert environmental disaster and ended up accidentally promoting the economics of the slave trade. It shows how human lives can be priced and exchanged for goods and services...

Stern's methodology has a disastrous consequence, unintended but surely obvious. His report shows that the dollar losses of failing to prevent a high degree of global warming outweigh the dollar savings arising from not taking action. It therefore makes economic sense to try to stop runaway climate change. But what if the result had been different? What if he had discovered that the profits to be made from burning more fossil fuels exceeded the social cost of carbon? We would then find that it makes economic sense to kill people.