Detroit – It is an environmentalist mantra that going green creates jobs and economic growth. “Green is Green.”

Take “greener” autos for example. “(Americans) need us to pass an energy policy that works with automakers to raise fuel standards (by 2020) . . . an energy policy that will create millions of new jobs that pay well and can’t be outsourced,” Barack Obama preached Wednesday, echoing the Goracle and others.

Well, America just got that fuel standard a decade early — by means of $4 a gallon gas — and it is anything but a job maker as Americans abandon gas-guzzling SUVs for smaller, “greener” cars. The math is simple really: Smaller cars mean smaller profits. And smaller profits mean less jobs and more outsourcing.

As Detroit automakers scramble to adapt from a 60/40 SUV-to-sedan mix to a 40/60 SUV-to-sedan mix, industry analysts are kissing goodbye the days when automakers sold 17 million vehicles year and light trucks minted money at $5,000-plus per sale.

Industry analysts like Ward’s now are predicting a return to annual sales in the mid-14 million range, which the U.S. hasn’t seen since 1993. Couple that with small car profits of just $1,500 each and green cars’ economic horsepower looks about as strong as, well, a 2.0-liter, 4-cylinder engine.

Oh, sure, Obama and his green disciples will do plenty of photo-ops with new technologies like the two-seat, plug-in electric Chevy Volt. “GM claims the Volt delivers triple-digit fuel economy and can travel up to 640 miles without a fuel fill-up or a battery recharge,” reports Edmunds.com. The key word there is “claims.” The Volt’s plug-in technology is yet to be proven in the marketplace. General Motors hopes to sell 10,000 in 2010.

Meanwhile, monthly sales of the Chevy Silverado truck alone were off 26,000 units this May compared to a year ago, as SUV sales are in free fall thanks to “planet-friendly” gas prices. And consider this: GM will sell the Volt at a loss (as it is presently doing on its hybrid models in order to build buyer interest) — whereas the Silverado brings in a staggering $10,000 per vehicle.

The Volt’s payoff, if it comes, is a long way off. This week, however, the Big Three idled light truck factories in Wisconsin and Ohio and cut shifts at others while ramping up production in its Lordstown, Ohio plant which makes the compact Chevy Cobalt.

But don’t think Lordstown is feeling comfortable. In fact, local officials say they get little sleep because low-profit margin vehicles like the Cobalt mean the U.S. plants that manufacture them are always on the bubble to be outsourced to low-wage countries like Mexico.

Greens may be thrilled by the shift to small cars and the resulting reduction in fuel consumption. But it is a recipe for tighter margins and shuttered U.S. factories – exactly the opposite of what enviro-priests preach.

As with climate science, greens’ grasp of economics is decidedly half-baked.