More than 225 businesses in the Boston area have issued a letter urging governors to support and improve the Regional Greenhouse Gas Initiative. Gov. John Lynch recently vetoed a bill that would have removed New Hampshire from RGGI, a cap-and-trade program aimed at reducing greenhouse gas emissions.

Ten Northeastern states currently participate in RGGI, including all six New England states. The program is aimed at reducing CO2 emissions from the power sector by 10 percent by 2018. Participating states sell emission allowances to power plants and use the proceeds to support clean energy programs and technologies.

The letter, coordinated by the New England Clean Energy Council, calls for governors of RGGI states to support the initiative and improve it by updating the emissions cap and increasing the scope by reaching out to other states.

“We believe strong clean energy and clean air policies create jobs and stimulate economic growth. RGGI shows that market-based programs can reduce greenhouse gas emissions while boosting our economy,” the letter reads. “By reducing spending on out-of-region fossil fuels, RGGI improves energy security and economic competitiveness and frees up energy dollars for spending in other parts of our economies.”

The letter comes in preparation for a 2012 program review, which will evaluate RGGI’s success and impacts to date. A Brookings Institution report released in July indicates the green economy now employs 466,000 people in RGGI states and 2.7 million people across the nation, which is more than the fossil fuel industry.

Although the original legislation that brought New Hampshire into RGGI received bipartisan support, many Republicans in the current Legislature oppose the program, saying it limits businesses and damages the economy.

On July 6, Lynch vetoed Senate Bill 154, which would have repealed New Hampshire’s participation in the initiative. Lynch said remaining in the program is vital to the state’s long-term economic competitiveness. He pointed to an independent assessment conducted by the University of New Hampshire indicating RGGI had generated $16 million in allowance revenue through 2010.