windPresenting Part Seven of a Ten-Part Series on The Future of Work from Time Magazine.

By Bryan Walsh at Time.

It’s no secret that U.S. workers are in trouble, with the unemployment rate at 8.9% and rising. At the same time, the world faces a long-term climate crisis.

But what if there is a way to solve both problems with one policy? A number of environmentalists and economists believe that by implementing a comprehensive energy program, we can not only avert the worst consequences of climate change but also create millions of new jobs — green jobs — in the U.S. “We can allow climate change to wreak unnatural havoc, or we can create jobs preventing its worst effects,” President Barack Obama said recently. “We know the right choice.”

What’s a green job? It depends on whom you ask. Some categories are obvious: if you’re churning out solar panels, you’re getting a green paycheck. But by some counts, so are steelworkers whose product goes into wind turbines or contractors who weatherize homes. According to a report by the U.S. Conference of Mayors, there are already more than 750,000 green jobs in the U.S. (See the top green companies.)

Environmental advocates say that with the right policies, those job figures could swell. The Mayors’ report predicts that for the next three decades, green employment could provide up to 10% of all job growth. As part of its stimulus package, the White House directed more than $60 billion to clean-energy projects, including $600 million for green-job-training programs. The hope is that capping carbon emissions, even if it raises energy prices in the short term, will create a demand for green jobs, which could provide meaningful work for America’s blue collar unemployed.

To some critics, that sounds too good to be true. In a recent report, University of Illinois law professor Andrew Morriss argued that estimates of the potential for green employment vary wildly and that government subsidies would be less efficient — and produce lower job growth — than the free market. “This is all smoke and mirrors,” says Morriss. “I don’t see how you can replace the existing jobs that may be lost.”

The reality is somewhere between the skeptics and the starry-eyed greens. We won’t be able to create a solar job for every unemployed autoworker. But with climate change a real threat, shifting jobs from industries that harm the earth to ones that sustain it will become an economic imperative.