The findings are not isolated. Research published this month by Ian Parry and Chandara Veung of the International Monetary Fund and Dirk Heine of the University of Bologna concluded that almost every one of the top 20 carbon emitters would reap economic gains by imposing a hefty carbon tax, if they deployed the revenue to reduce taxes on income.

A tax of $63 per ton of CO 2 , for instance, would not only cut China’s emissions by some 17 percent, it would also cut the number of Chinese sickened or killed by pollution from coal. If Beijing used the money to cut other taxes, it would increase economic efficiency, adding up to a net economic gain — on top of any climate impact — of more than 1 percent of China’s gross domestic product.

This finding does not depend on any technological breakthroughs. It happens whether solar energy is cheap or expensive.

“It’s only recently that policy makers are beginning to appreciate the power of fiscal instruments like environmental taxes,” Mr. Parry told me. “And it’s only fairly recently that we’ve been able to value the health and other environment impacts so we’ve only recently got some sense of the substantial and pervasive undercharging for environmental damages.”

Image President Obama with Secretary General Ban Ki-moon, right, and General Assembly President Sam Kutesa, after Mr. Obama’s U.N. address. Credit Richard Drew/Associated Press

While this is all theory, some empirical research also supports the finding.

In 2008, for instance, the Canadian province of British Columbia unilaterally imposed a carbon tax that rose from 10 Canadian dollars per ton of CO 2 in 2010 to 30 dollars in 2012, using the money to reduce personal and corporate income taxes.

An assessment of the experience published last year by economists at the Organization for Economic Cooperation and Development found that fuel use declined, but economic growth remained on the same trajectory as the rest of Canada’s. Notably, British Columbia ended up with the lowest income tax in the country.

Could this new understanding change the debate over climate change?

At the very least, the belief that there is a climate-related free lunch out there might provide welcome harmony to negotiations that usually end in acrimonious finger-pointing. The new research might even help move the debate away from the failed strategy of seeking legally binding emissions targets on every country, providing a blueprint for countries to voluntarily take on ambitious goals because it is in their own self-interest regardless of what other nations do.