Climate Chief Melissa Hoffer wrapped up her final day in the position on Monday. STATE HOUSE NEWS SERVICE

BOSTON — Melissa Hoffer, the nation’s first Cabinet-level climate chief, used her final day in the Healey administration to deliver a message to Massachusetts environmental advocates: The transition to a cleaner economy cannot succeed politically unless people understand that climate action and affordability go hand in hand.

Speaking Monday during a virtual farewell address hosted by the Massachusetts Climate Action Network, Hoffer celebrated what she described as significant progress under Gov. Maura Healey while urging advocates to defend clean energy programs, push for new financing mechanisms and remain vocal as the administration’s energy policies increasingly emphasize affordability.

Her departure also leaves questions about the future of the Cabinet-level job that Healey established as a centerpiece of her first term climate agenda, including exactly how much influence the office will retain as the administration embraces an increasingly expansive approach to energy supply that includes natural gas.

Hoffer’s farewell address exposed some of that tension at the center of Healey’s energy policy. While the climate chief urged advocates to push for an eventual end to natural gas infrastructure, Healey has increasingly emphasized the need for additional gas supplies, arguing that pipeline expansions can help lower energy costs.

The discord is not just over the state’s long-term climate ambitions, but over what affordability requires in the meantime — and how much new investment in fossil fuel infrastructure Massachusetts should be making as it works toward its 2050 climate mandates.

Hoffer, who is leaving to become president of Vermont Law and Graduate School, was announced as the school’s incoming president in August. Her new position is scheduled to begin Dec. 1.

The administration said when her departure was announced that Healey would name a successor before Hoffer left. No successor had been publicly announced as of Monday, her last day. Hoffer’s office did not reply to a question Tuesday about the governor’s plan and timelines to appoint a new climate chief.

Healey created the climate chief position on her first day in office in January 2023, establishing the Office of Climate Innovation and Resilience within the governor’s office. The appointment was intended to ensure climate considerations extended beyond traditional environmental and energy agencies and informed decisions across state government.

“On day one of this administration, we created the Office of Climate Innovation and Resilience and appointed the nation’s first cabinet-level Climate Chief because we know that addressing the climate crisis requires a comprehensive, coordinated approach across all of state government,” Healey said in October 2023.

At the time, Healey said Hoffer’s recommendations would help advance “the ambitious climate and clean energy policies that we need to protect our future and power our economy.”

Hoffer reflected Monday on that whole-of-government approach, saying she believed it had been successful in bringing climate considerations into state agencies and quasi-public organizations.

The outgoing climate chief also sought to counter the argument that environmental protections and clean energy investments necessarily conflict with household affordability.

“What is affordable is green. What is affordable is clean energy. What is affordable is investing in resilience now,” Hoffer said.

Hoffer invoked the long-running conflict over logging and the protection of the spotted owl as a cautionary example of what happens when environmental policy is framed as a choice between conservation and working-class economic interests.

“This is one of those situations where we must do everything we can to avoid running into a situation where people see it as a competition between, it’s either going to be affordable or it’s going to be green, because that’s malarkey,” she said.

She urged advocates to make that case directly to lawmakers, local officials and residents, warning against allowing climate policy to become framed as a choice between environmental protection and economic security.

That affordability argument takes on particular significance as Healey pursues an energy strategy that explicitly includes natural gas, even as the state remains legally committed to reaching net-zero greenhouse gas emissions by 2050.

In an October letter to U.S. Energy Secretary Chris Wright, Healey urged the Trump administration to expedite federal review of the proposed Algonquin Reliable Affordable Resilient Enhancement, or RARE, pipeline project. The governor’s office says the project could lower costs for Massachusetts customers by reducing reliance on more expensive imported liquefied natural gas delivered through the Everett terminal.

“I’ve been clear that we need to bring more energy supply into Massachusetts with an all-of-the-above approach that includes solar, wind, storage, nuclear, geothermal, hydro and gas,” Healey said in a statement announcing the request.

Asked Monday what she would change if she had a “magic wand” to remove systemic obstacles to climate progress, Hoffer offered a blunt answer.

“We should be putting in place a hard stop on natural gas infrastructure,” she said. “It should be phased out by 2050.”

She described methane as “a super pollutant.”

Hoffer did qualify the proposal, emphasizing that the transitions would have to be orderly and that the state could not simply stop using its existing gas infrastructure immediately. She also acknowledged that she was answering in a hypothetical scenario in which political considerations did not constrain policymakers.

“I’m answering you in a magic world where politics don’t matter because you gave me my wand,” she said, “But if we are looking at science, that’s what we should be doing.”

The outgoing climate chief also argued that continuing to invest in both gas and electric infrastructure risks saddling customers with costs for assets that may become unnecessary as more homes and businesses electrify.

Hoffer said the state’s current approach effectively requires customers to pay for two energy systems simultaneously, even as policymakers anticipate a gradual transition toward electrification.

“We’re expanding the electric system and we’re expanding the gas system, and we’re paying for stuff that we don’t need,” she said.

In responding to an audience question about stranded gas assets, Hoffer pointed to Healey’s energy affordability legislation, which proposes integrated gas and electric planning. She said utilities need to coordinate their planning so that areas expected to transition to heat pumps and other electric technologies do not continue receiving unnecessary gas infrastructure investments.

“Right now we’re running two systems next to each other, and we have to do that for safety and reliability,” Hoffer said, adding that the state needs to identify where it can “prudently prune back” gas infrastructure.

She argued that better transparency and planning by utilities, as well as greater oversight by the Department of Public Utilities, would help avoid investments that ratepayers ultimately would have to pay for even if the infrastructure is no longer needed.

But that longer-term planning framework sits alongside an administration that is actively supporting additional gas supply when officials believe it will reduce near-term costs.

The RARE project is not the only potential expansion under discussion. Enbridge has also proposed a second expansion of the Algonquin pipeline, known as Project Beacon, which would increase natural gas flows into the region. Healey has not clearly outlined her position on that proposal.

The administration has said its support for RARE is on the grounds that the project would be funded by its developer rather than through additional costs to ratepayers. In January, after state regulators approved an Eversource supply contract tied to the expansion, Healey said the decision would lower costs for more than 600,000 gas customers.

Hoffer also acknowledged the political constraints facing governors as the Trump administration moves against federal climate programs, describing the challenge of maintaining state commitments while avoiding federal retaliation.

As an example, she pointed to the cancellation and disruption of offshore wind investments, which she said had dealt a significant blow to the state’s reliability planning and climate goals.

“As a governor, not just Governor Healey, but you saw many governors really trying to thread that needle, where you would cleave to your strong values and your state commitments, but not try to get on his bad side,” Hoffer said.

Her departure comes with questions about the administration’s second term climate agenda, and how it fits in with affordability. For Hoffer, the central message to advocates was that those priorities should not be treated as competing interests.

“What we can’t do is take that bait that somehow it’s just too expensive for us to deal with climate change,” she said. “Because I’ll tell you what’s really expensive: that is, climate change.”