Economist Kenneth Boulding famously said, “Anyone who believes exponential growth can go on forever in a finite world is either a madman or an economist.” But it's not just economists who believe that anymore. Such ideas are still widely accepted by thought leaders, journalists, and politicians who, together, form a strong consensus that the U.S. recovery should be bolstered by natural gas exploration and production. The McKinsey Global Institute claims in a recent report that a natural gas boom is one of the most important “game changer” ideas for U.S. economic growth, while The Economist writes, “Become a champion of a global fracking revolution, Mr. Obama, and the world could look on America very differently.” And in his recent State of the Union address, President Barack Obama said "I'll cut red tape" for factories that use natural gas, and that "Congress can help by putting people to work building fueling stations that shift more cars and trucks from foreign oil to American natural gas."

But the belief that natural gas can be a “bridge fuel,” allowing us to grow rapidly in the age of global warming, is fit for a madman.

The current consensus is that if global temperatures rise more than 2 degrees Celsius above preindustrial levels, the consequences would be catastrophic (the Arctic melt would raise sea levels by tens of meters). So scientists have proposed a “carbon budget”: the total amount of carbon dioxide that can be released into the atmosphere without raising temperatures by 2 degrees. Using a conservative carbon budget of 450 parts per million—which has been endorsed by the International Energy Agency and Britain's Stern Review—economists Humberto Llavador, John Roemer, and Joaquim Silvestre have thrown cold water on the idea that natural gas is our nation's economic savior. In a forthcoming paper, they argue that given that budget, the world's two largest CO2 emitters, the U.S. and China, must keep GDP growth within the threshold of 1 percent and 2.8 percent of GDP per year, respectively, for the next 75 years.

These results may sound surprising, but they are in line with a growing body of research on stranded carbon assets, which are assets such as fossil fuels (oil, coal and natural gas) that will lose their value well before they're expected to. This can happen as a result of, say, market disruption (rapid advances in green technology like wind and solar polar or divestment) or government regulation (a carbon tax or stricter fuel economy standards). That latter is more likely because, even now, we have found way more fossil fuels than we could possibly burn without inviting long-term environmental disaster.

The Intergovernmental Panel on Climate Change's carbon-budget model, widely considered the most reliable, puts the budget for 2012-2100 at between 886 and 1119 gigatons of CO2. Total known fossil fuel reserves in the world, if burned, would add 2860 gigatons of CO2 to the atmosphere. Thus, simple math indicates that almost two-thirds of all known fossil fuel reserves must remain unburned if global temperatures are to remain habitable. And these are optimistic estimates. James Hansen of the Columbia Earth Institute and other leading scientists and economists argue that all extraction of coal and other unconventional fossil fuels, like the Canadian Tar Sands, must cease immediately and the extraction of conventional fossil fuels, like oil and natural gas, must be significantly pared down.