MIAMI (Reuters) - The U.S. economy could generate 4.2 million new "green" jobs in the next 30 years, about 10 percent of all the jobs created, according to a study for the U.S. Conference of Mayors released on Thursday.
The study found the United States now has about 750,000 green jobs, which generally involve producing renewable energy or providing engineering, legal or research support.
That figure represents less than 0.5 percent of all current U.S. jobs, said Global Insight, the economic research and consulting firm that did the study.
The study is the first attempt to quantify the economic opportunity presented by a drive by U.S. cities and states to boost energy efficiency and reduce greenhouse gases and the use of fossil fuels, the group said.
"We are firmly convinced that what we need in this country is a green revolution," Miami Mayor Manny Diaz, president of the U.S. Conference of Mayors, said at a news conference.
The study was released on the same day that the number of U.S. workers filing new claims for jobless benefits rose to 497,000, the highest number in seven years.
The forecast of 4.2 million new green jobs is based on the assumption that 40 percent of the electricity generated in the United States by 2038 will come from alternative fuels -- wind, solar, hydro, geothermal and biomass.
It also assumes that 30 percent of fuel used in cars and light trucks will come from alternatives to gasoline and diesel by then, and that electricity use in existing buildings will drop by 35 percent due to retrofitting.
The study said the push to increase the use of alternative fuels in transportation alone could generate nearly 1.5 million new jobs in the next three decades.
Spurred by Washington's failure to enact global emissions standards in the United States, the world's biggest polluter, members of the U.S. Conference of Mayors have moved to enact elements of the Kyoto Protocol -- a climate change pact agreed to by governments at a 1997 U.N. conference in Japan -- in their own cities.
Many states also have set their own targets. For example, Florida last year called on state utilities to produce 20 percent of their power from renewable sources by 2020 and to reduce greenhouse gas emissions to year 2000 levels by 2017.
The study defined current green jobs as those focused on generating electricity from renewable or nuclear fuels, supplying corn or soy for fuel, making or selling renewable power equipment, and building and installing energy or pollution management systems.
It also listed government environmental jobs or support jobs in engineering, legal, research and consulting.
The largest number of current green jobs -- nearly 420,000 of the 750,000 -- are in engineering, legal, research and consulting, the study found. The second largest field, with 127,000 jobs, was renewable power generation.
Some 85 percent of current green jobs are in metropolitan areas, with the largest number being in New York, followed by Washington, Houston and Los Angeles.
Editing by Jane Sutton and Xavier Briand