As the battle over climate change legislation heats up, several Big Green groups -- the Environmental Defense Fund, the Natural Resources Defense Council and the Sierra Club -- are rolling out TV and Internet ads designed to persuade voters that regulating greenhouse gas emissions will create green jobs. David Yarnold, the president of EDF's Action Fund, sums up the message in an email: "Carbon Caps = Hard Hats." Clever.

Here's an ad from EDF's campaign, launched in partnership with the United Steelworkers union and the Blue Green alliance, a group of enviromental groups and unions.



Think of this ad, and the one below, as the "Harry and Louise" ads of the campaign to pass global warming legislation. You remember Harry and Louise, right? They were the couple who turned a devilishly complicated issue, health care reform, into a soundbite ("If we let the government choose, we lose") and helped kill the 1994 Clinton health plan. These ads take what may be an even more devilishly complicated issue, climate change regulation, and use images of brawny construction workers to turn it into an even shorter soundbite: "Green jobs." Take a look at this spot from The Blue Green Alliance:



Maybe I missed it, but did you hear an environmental message in either of those ads?

Of course, there's research to support the claims about green jobs. In the interests of full disclosure, I need to say here that I've been doing some freelance work for EDF and NRDC -- organizations I admire a great deal. But these claims about green jobs deserve greater scrutiny.

Last June, for example, the Blue Green Alliance, Sierra Club, NRDC and the steelworkers issued a green jobs report from the Political Economy Research Institute (PERI) at the University of Massachusetts, Amherst. It said:
"…millions of U.S. workers -- across a wide range of familiar occupations, states, and income and skill levels -- will benefit from the project of defeating global warming and transforming the United States into a green economy."
A second report from PERI, issued last September under the auspices of the Center for American Progress, got more granular. In my home state of Maryland, for example, the authors project that a $100 billion green economic recovery program would create 36,739 jobs. They would be created in such industries as building retrofitting, mass transit and freight rail, smart grid, wind power, solar power and advanced biofuels.

It sounds great, doesn't it?

Not according to the four lawyers and economists who produced "7 Myths About Green Jobs," a 97-page report published by the University of Illinois College of Law. They argue that "the green jobs literature is rife with internal contradictions, vague terminology, dubious science, and ignorance of basic economic principles."

Studies by conservative think tanks go further, claiming that climate legislation will destroy millions of jobs. A 2008 Heritage Foundation study claimed that passage of last year's Lieberman-Warner bill would create "extraordinary perils for the American economy" and cause annual job losses of between 500,000 and 1,000,000 after a few years of job gains. (This report was pretty thoroughly discredited by NRDC.)

The best thing I've read about this debate (and one of the most balanced) is this fine Slate article by Eric Pooley, my former editor at FORTUNE, who finds that there's an emerging economic consensus that the costs of dealing with climate change are significant but manageable -- and that given the risks, those costs are likely worth paying.

My point here is not that economists disagree. My point is that the climate change debate shouldn't be about green jobs.

It's intellectually dishonest to pretend that we can forecast, with any degree of accuracy, the impact of a complicated government policy on a dynamic global economy decades into the future. Both sides know that their projections are based on a host of assumptions which may or may not come true.

What if we decide as a nation to turn to nuclear energy as a source of low-carbon power? That probably won't create many long-term jobs. What if there's a breakthrough in the solar PV business in China? That may not bring green jobs here. Are farmers who grow corn for ethanol doing green jobs? That hasn't turned out so well.

Let's get real: We can't predict oil prices 12 months out. Last spring, virtually no one anticipated the global financial crisis of last fall. And we are projecting the number of green jobs that will be created or lost on a state-by-state basis by a law that won’t take effect until 2012? Who are we kidding?

I called Russ Roberts, an economist at George Mason University who hosts the fine EconTalk podcast, for some guidance on how to think about green jobs and the economics of climate regulation.  "Creating green jobs is easy," he told me. "We could employ millions of people picking up litter, and we could make them very good-paying jobs if we want. But of course that would make us poorer as a nation. There’s a cost to providing those jobs that would have to be borne by other people in the economy."

It's not just the cost of higher taxes that needs to be factored into the equation, he noted. To the degree that the government makes policy that favors, say, vast construction of wind turbines throughout the upper Midwest, the people doing those jobs will be drawn from somewhere else, maybe even from more productive work. If policy leads to the hiring of  thousands of contractors to do energy efficiency, the cost of building a new home or renovating your basement may go up because many of the good construction workers are busy.

"As voters and citizens and readers, what we want to think about is the big picture -- are we moving in the right direction when it comes to environmental policy?" Roberts says. Put another way, are we spending enough money today to head off the threat of global warming in the future? Because if anyone tells you that we can deal with climate change at no cost, they probably shouldn’t be trusted.

Maybe that's what bothers me about the green jobs ads. They're like political campaign ads. They promise something for nothing. They treat the voters like children. They're emotional and not educational. And they're not helping to build a movement around climate change.

Other than that, they're fine.

And I do hope they work.

Ironworker image CC licensed by Flickr user Paul Keleher.