Economic gains caused by man-made climate change will outweigh the losses in developed, mid-latitude countries like the United Kingdom, the Yale University economists said. Much of the improvements will come from the beneficial effects on plants.
The biggest winners of all will be the three nations which have the worst track record on producing "greenhouse gases" - Russia, Canada and the US.
The claims, made at a seminar organised by oil companies including BP and Shell, were dismissed by a leading environmental organisation as complacent and suspect.
But they show how the global warming debate has been transformed within the past two years.
No longer do major producers and consumers of fossil fuels such as the oil giants, who have most to lose from policies to tackle the threat, dispute that global warming will happen in the next century. Now they are questioning whether anything much needs to be done about it.
Professor Robert Mendelsohn unveiled the results of wide-ranging studies into the impact of warming on the US. By 2060, he forecast, GDP would be about $40bn (pounds 27bn) a year higher than it would if there had been no climate change. Similar results were expected for northern Europe.
Merylyn McKenzie Hedger of the World Wide Fund for Nature said the studies "reveal great complacency. There are these underlying planetary life support systems, such as habitats, which they ignore".