Over the past decade, Massachusetts has made significant progress in reducing its carbon emissions, primarily by curbing pollution from power plants.
Now comes the hard part — limiting emissions from cars and other vehicles, which have surpassed power plants as the state’s largest source of greenhouse gases.
The Baker administration is considering sweeping measures that could transform the state’s transportation system, which is responsible for about 40 percent of emissions.
It’s a politically risky undertaking, and potential solutions — from raising the gas tax to increasing tolls to investing more in public transportation — could be expensive and unpopular. But without aggressive reductions in transportation emissions, progress on climate change can only go so far.
“We need to figure out what’s going to be a major transformative effort, and the least disruptive way to do it,” said Matthew Beaton, the state’s secretary of energy and environmental affairs, who this month began holding public meetings around the state to discuss potential policies.
Among the questions Beaton and others are wrestling with — how to drastically reduce the use of fossil fuels without slowing the economy, how to pay for roads and bridges if electricity increasingly replaces gasoline as a fuel, and whether the state should subsidize the building of charging stations for electric vehicles and provide other incentives to accelerate the transition.
One potential solution now under consideration would be a regional cap-and-trade system for transportation emissions, similar to the nine-state Regional Greenhouse Gas Initiative, known as RGGI. That coalition, widely seen as a national model, has reduced power plant emissions from Maryland to Maine by about 40 percent below 2005 levels, without raising average electricity prices.
Officials from many of those states, including Massachusetts, released a joint statement on Monday that could ultimately lay the groundwork for a similar initiative. With some of their representatives now in Bonn, where environmental officials from around the world have gathered for a United Nations conference, they hoped to show that the United States is still acting to address climate change, even if the federal government has abandoned such efforts.
“We recognize that a regional solution that reflects the regional nature of the transportation system will be more beneficial to our residents and businesses,” wrote officials in the statement from Massachusetts, Connecticut, Vermont, Rhode Island, New York, Maryland, Delaware, and the District of Columbia.
Environmental advocates throughout the region have urged state officials to follow the RGGI’s model by creating a regional group that would set a limit on overall transportation emissions and require fuel distributors in member states to buy pollution allowances based on their emissions.
The money raised from those allowances, which would become more stringent over time, could be used by the states to upgrade their transportation systems. In Massachusetts, it could be used to finance MBTA stations and other public transit projects, fast-charging stations for electric vehicles, car-pooling and driverless car services, new bike lanes, and subsidies to accelerate the adoption of electric vehicles.
“We can build on the RGGI success with a similar ‘cap-and-invest’ program that uses market forces and public investments to scale up clean and affordable transportation for all,” said Ken Kimmell, president of the Union of Concerned Scientists in Cambridge.
He praised the joint statement, in which the states promised to host listening sessions like those in Massachusetts to consider potential policies.
The effort could be vital to the legal requirements in Massachusetts to reduce emissions. Under a landmark 2008 state law that mandated aggressive action against climate change, Massachusetts must reduce greenhouse gases 80 percent below 1990 levels by 2050.
While power plant emissions have dropped sharply since the RGGI took effect in 2009 — they’re required to fall 65 percent below 2005 levels by 2030 — transportation emissions have remained flat.
A regional cap-and-trade system for transportation emissions would address that directly, and it could also help retain more of the money that Massachusetts residents spend on fuel. Much of the revenue from the gasoline that drivers buy now goes to companies outside the state.
“We spend over $11 billion a year on gasoline, and all of that money leaves the region,” said Jordan Stutt, a policy analyst at the Acadia Center, an environmental advocacy group in Boston. “If we move away from gas toward electricity, we can keep more of that money here and move the transportation system forward.”
Representatives of power plants in the region, which now support the RGGI, say it’s time for other sectors of the economy to share the burden.
In a letter sent this month to the governors of Massachusetts, Vermont, Connecticut, and Rhode Island, officials from the New England Power Generators Association urged them to sign an agreement next year to launch a cap-and-trade system for transportation emissions. Power plants now account for about 17 percent of carbon dioxide produced in the region.
“If market-based policies are applied to transportation, we believe that RGGI’s benefits would be replicated,” they wrote in the letter, which was also signed by several environmental groups.
Beaton and other state officials have declined to comment on the proposal, beyond saying that they have been discussing the issue with their counterparts in other states.
But they acknowledge that any plan to reduce transportation emissions would benefit from a regional approach. In part because of the RGGI, Massachusetts has already cut its greenhouse gas emissions about 21 percent below 1990 levels, and Beaton says the state is on track to reduce it by the mandated 25 percent by the end of the decade.
“It’s great if we have a great policy in Massachusetts, but your electric vehicle won’t care if you’re in Massachusetts or New York,” he said. “We need to create a regional infrastructure.”
While environmental advocates say they’re pleased with the state’s approach so far, some lawmakers say they’re concerned that the Baker administration is more interested in talking about the issues than taking action.
“The state’s listening tour could be much ado about nothing, and I’m not yet convinced they’re serious about moving beyond talking, listening, and chin-stroking,” said state Senator Michael J. Barrett, a Lexington Democrat who chairs the Legislature’s Joint Committee on Telecommunications, Utilities, and Energy.
Barrett supports a regional system similar to the RGGI, but also wants Massachusetts to take immediate action on its own.
A simple, effective way to reduce transportation emissions, he said, would be for the state to unilaterally impose a higher price on gas and other fossil fuels. The higher the price, the less carbon pollution, he said.
“You can’t be serious about this issue without putting a price on carbon,” he said.
Barrett has proposed a bill, modeled after a similar policy in British Columbia, that would increase the tax on a gallon of gas from 8 cents to 36 cents over seven years. He describes the plan as a carbon fee, since the revenue would be returned to the public in the form of a rebate.
Critics of his bill have noted that previous hikes in gas prices have only led to modest reductions in driving, and state officials said they oppose such efforts.
“The administration does not support implementing any additional ‘carbon tax’ that would adversely impact businesses’ and families’ utility bills,” said Brendan Moss, a spokesman for Baker.
Before the RGGI was adopted throughout the region, critics raised similar concerns that exacting a price on power plant emissions would increase electricity costs.
It’s one of the reasons that Governor Chris Christie of New Jersey gave for pulling out of the pact in 2011.
But electricity prices in RGGI states have actually fallen by 6.4 percent since the initiative took effect, while electricity prices in the rest of the country increased 6.2 percent. Now, with the election of a new Democratic governor, New Jersey is poised to return to the RGGI.
At Massachusetts’s first public meeting on the emissions issue in Boston last month, where residents, advocates, and state officials spent a morning brainstorming ideas in small groups, Chris Coil, a spokesman for the initiative, said he expects more conversations in the region will ultimately lead to new policies.
“There’s going to be a huge boom for those states that do take action,” he said.
David Abel can be reached at email@example.com. Follow him on Twitter @davabel.