OPPONENTS OF THE regional effort to wring carbon emission reductions from cars, trucks and other forms of transportation predicted Thursday that Massachusetts residents could face fuel shortages as soon as 2025 unless the state can dramatically scale up the transition to electric vehicles.

The claims, however, were quickly discounted by the designers of the multi-state program who said the warnings were just wrong and ignored the beneficial impacts over time of investing in clean energy alternatives to gas-powered vehicles.

Massachusetts is one of three states, along with the District of Columbia, invested in launching a cap-and-trade program, known as the Transportation and Climate Initiative (TCI), by 2023.

The governors of Connecticut and Rhode Island are in the process of working with lawmakers in their states to secure approval to move forward, while eight other states have not formally signed onto TCI but remain involved in the planning, according to the Georgetown Climate Center.

The program has been billed as a way to reduce carbon emission by 26 percent by 2032 by capping pollution from motor gasoline and on-road diesel, and investing the proceeds from the sale of carbon allowances into clean energy alternatives, such as electric cars and buses.

While TCI is projected to increase gas prices on consumers by between 5 cents and 9 cents per gallon, it’s been estimated that participating states like Massachusetts could net hundreds of millions of dollars to finance energy efficiency projects.

In raising the specter of fuel supply shortages, the Massachusetts Fiscal Alliance Foundation and a Connecticut group representing gas stations and wholesale fuel suppliers evoked images of lines at gas pumps and empty toilet paper shelves.

“Everyone knows about the shortages caused by COVID. There were toilet paper, cleaning supplies, people rushed to the stores, the shelves were empty, prices spiked and people couldn’t find the product anymore. That is the kind of thing we’re predicting for TCI if the slack in the amount of fuel that can be sold isn’t offset by increases in [electric vehicle] sales,” David Chu, vice president of the Connecticut Energy Marketers Association, said.

Chu predicted that Massachusetts would have to reduce fuel usage by 52 million gallons by 2025 in order to keep on track to meet TCI’s goal of a 30 percent reduction in the cap on carbon pollution by 2032, requiring a significant decrease in travel by Massachusetts residents, or the replacement of nearly 80,000 gas- and diesel-powered vehicles over the next four years.

The designers of the Transportation Climate Initiative said Chu’s analysis was completely wrong, ignoring the flexibility and periodic reviews built into the program to ensure demand is not exceeding expectations.

Furthermore, officials said MassFiscal and CEMA were ignoring the potential for emission reductions to occur as a result of TCI proceeds being reinvested by states into clean energy or the federal government doing more over the next decade to incentivize electric vehicles sales or set stronger fuel emission standards for gas-powered vehicles.

“TCI-P will cut greenhouse gas pollution from motor vehicles in the region by an estimated 26% from 2022 to 2032, and generate a total of more than $3 billion dollars over ten years for participating jurisdictions to invest in equitable, less polluting transportation options and help stimulate economic recovery,” said James Bradbury, mitigation programs director for the Georgetown Climate Center.

TCI does not cap fuel sales by volume, but Chu said for every metric ton of carbon dioxide TCI aims to eliminate it must cut 122 million gallons of fuel from the supply chain.

That number of cars and trucks that would have to be replaced with electric vehicles grows to 217,513 vehicles by 2026, Chu said.

TCI officials said the CEMA analysis relies on “unrealistic” assumptions and a “deliberate misinterpretation” of US Energy Information Administration data that inflates projected fuel use by accounting for fuels, such as off-road diesel and ethanol, that are not covered by TCI.

Paul Craney, the spokesman for the MassFiscal Foundation and a leading opponent of TCI, pointed to state data showing that roughly 12,000 electric vehicles have been put on the road since 2014 and 2,000 electric vehicles were sold last year. The need, Craney said, will actually be 2,000 per month.

“Clearly Massachusetts is not prepared for what is about to happen if we continue with the TCI plan,” Craney said.

Proponents of TCI, including the Baker administration, argue the cap-and-trade program would generate hundreds of millions of dollars for Massachusetts that could be invested in clean energy programs that will help drive down emissions.

Energy and Environmental Affairs Secretary Kathleen Theoharides has said the state would look to invest in electrification of public transit, charging corridors for electric vehicles, more electric buses, ways to make it easier to walk and bike, and telecommuting infrastructure for more rural areas.

The Baker administration has remained optimistic about the prospects for TCI as a key component of its climate change agenda, which includes achieving net-zero carbon emissions by 2050, even as other states have struggled to get the necessary sign-offs from political leaders to push ahead.

The memorandum of understanding signed by Massachusetts, Connecticut, Rhode Island and DC calls for the program to formally launch in 2023.