There’s good news for the future of green-collar employment, but it comes with a caveat: maximizing job growth in green industries will require the right public policy support. That means law-makers need to approve measures such as a renewable portfolio standard, incentives for renewable energy, public education programs and adequate funding for research and development.

If such measures are put in place, the U.S. could see as many as one out of every four workers employed by a renewable-energy or energy-efficiency industry by 2030, according to a new report from the American Solar Energy Society (ASES). That’s promising for both U.S. employees and for anyone concerned about reducing greenhouse gas emissions and our dependence on fossil fuels. But it will happen only, as the ASES report says, under “an aggressive deployment forecast scenario.”

That means we, as citizens and consumers, are going to have to apply strong and steady pressure on legislators — local, state and national — to do the right thing. And that, we all know, isn’t easy.

Still, if — as the saying goes — money walks, green-collar types might see Beltway support grow as green industries expand their economic muscle, which means more dollars for lobbying and campaign financing. And, in that regard, the future looks bright.

In the U.S., renewable-energy and energy-efficiency industries are already generating 8.5 million jobs and nearly $970 billion in annual revenues, according to the ASES report. “To put this in perspective,” the report states, “(t)otal sales for Wal-Mart, Exxon-Mobil and General Motors in 2006 were $905 billion.”

While companies on the energy-efficiency side — things like better windows, efficient appliances and insulation — are making more of the money right now, the renewables side is growing more rapidly.

The ASES predicts the hottest, fastest-growing industries will involve solar power, wind energy, ethanol and fuel-cell technologies. With the right level of public support, it says, we could see up to 40 million people employed — as everything from accountants and biochemists to engineers, mechanics and truck drivers — in the renewable-energy and energy-efficiency sectors by 2030, with annual green-industry revenues of $4.5 trillion.

Getting there, though, will require much more than a business-as-usual approach, the ASES report warns.

“This scenario requires appropriate, aggressive, sustained public policies at the federal and state level during next two decades,” it states. Getting decision-makers to come on board might take oil shortages, fossil-fuel price increases, growing security concerns or a greater awareness of the impact of climate change. The fear of suffering economically at a global level might also be a motivator.

“If we fail to invest in (renewable energy and energy efficiency), the United States runs the risk of losing ground to international … programs and industries,” the report concludes. “For the United States to be competitive in a carbon-constrained world, the (renewable energy and energy efficiency) industry will be a critical economic driver.”