Throughout the four years of the Biden-Harris administration, climate efforts saw unprecedented federal support, said local environmental leaders.

Now, those same leaders are bracing for limited leadership and investment at the national level as former President Donald Trump prepares for his return to the White House.

“We are truly in unchartered territories,” said Britteny Jenkins, vice president of environmental justice at the Conservation Law Foundation. “We can’t say we’ve been here before, because the truth is, we just truly haven’t.”

The shift comes at a moment as advocates say there is a heightened need to take climate action. Jenkins pointed to the day after the presidential election when temperatures in Boston neared 80 degrees.

According to the National Oceanic and Atmospheric Association, summer 2024 was the hottest in the northern hemisphere on record.

Throughout the past four years, federal funding under the Biden administration has been key to forwarding local climate efforts.

“Over the last several years in the Biden-Harris administration, we’ve had phenomenal partnership and seen some of the biggest investments we’ve ever seen in climate action coming from congress,” said Hessann Farooqi, executive director at the Boston Climate Action Network. “That has made so much of the work possible in infrastructure at the city and state level.”

In the Boston area, he pointed to steps like making buses fare-free, building out energy infrastructure and reducing diesel emissions.

Local leaders expect much of the support they’ve seen under the current administration to disappear when Trump’s administration takes over in January.

On Nov. 11, he announced his plans to nominate Lee Zeldin, a former New York representative, to head the Environmental Protection Agency.

While Zeldin has had a track record of pushing for coastal resilience and nature preservation projects in Congress, he never advanced proposals to cut greenhouse gas emissions. During his 2022 run for New York governor, part of his campaign included a promise to overturn the state’s ban on fracking.

In announcing Zeldin as his pick, Trump framed the choice as one with a focus on deregulation to promote U.S. businesses, but said the administration will maintain the “highest environmental standards.”

On Nov. 16, he selected Chris Wright, chief executive of fracking company Liberty Energy, to appoint to head the Department of Energy.

Under his first term in office, Trump rolled back nearly 100 federal environmental rules. The president-elect has waffled on how he describes climate change, sometimes calling it a hoax and other times saying the environment and issues like clean air are important to him (some of the first Trump administration efforts to rollback protections included revoking the waivers of 14 states that provided state-level authority to set standards on tailpipe admissions under the Clean Air Act).

Even with expectations of reduced federal support, elected officials at the city and state level said they’re prepared to keep pushing forward on goals around climate and environmental impacts.

“We have to follow the science; we’ve always followed the science in Boston and the reality on the ground,” said Brian Swett, Boston’s chief climate officer. “Elections don’t change the fact that climate change is the existential threat to Boston’s survival for the long term, and we need to address it, and we’re making progress on doing so.”

In some ways, limited federal investment in climate resilience isn’t new. Prior to the last four years, much of the work around climate change fell to city- and statelevel governments, Swett said. In that way, for the next four years, cities and states will continue to lead, he said.

“It wasn’t until, really the Biden-Harris administration that there was significant investments and action on climate,” Swett said. “For the last 25-odd years, it’s been cities and states leading the charge. To a significant degree, we’ve been leading, and the federal government has been catching up”

And even with the increased support from Washington, D.C., in the past few years, Massachusetts and Boston in particular have taken steps to bolster local climate resilience. Swett pointed to the city’s Building Emissions Reduction and Disclosure Ordinance — city legislation from 2021 requiring large buildings in Boston to reduce emissions with net-zero targets by 2050 — as well as new state legislation, passed Nov. 14, that takes steps regarding permitting for clean-energy infrastructure, expanding a network of electric vehicle chargers and incentivizing new clean technologies.

But that work from state leaders will be especially important in the federal vacuum, Jenkins said.

“We’re going to need them to fully lean in more than they ever had before, to address the climate crisis, to really be a leader on environmental justice,” she said.

“We will really be looking to them for leadership to essentially make up for the kind of leadership that is going to be lacking on the federal level.”

Like Swett, local environmental and conservation groups, also said emphasis on local efforts aren’t new.

For the Boston Climate Action Network, mobilizing to keep green efforts moving is familiar territory. The group formed in the aftermath of the 2000 election — when Democratic nominee and environmental advocate Al Gore lost the White House to Republican candidate George W. Bush — with the goal of advancing state and local environmental efforts in the absence of federal leadership.

“We were in a bit of a similar moment; we had hope of getting a lot more done at the federal level, but when that hope was then extinguished, we knew there was something that cities and states could do to help further climate action efforts,” Farooqi said. “That has not changed.”

And some are planning to push for continued environmental protections at a broader level. In addition to plans to continue advocacy at the state level, the Conservation Law Foundation is prepared to take issues around climate to the courts, Jenkins said.

During Trump’s first term in office, the Conservation Law Foundation took his administration to court on multiple occasions as Trump attempted to reduce the protections for national monuments or for rolling back clean water protections. Jenkins said the group is ready to do the same this time around.

“This is something that we at CLF have been preparing for,” she said. “We believe we’ll be able to meet the moment.”

But a conservative majority on the Supreme Court and Trump-appointed judges in federal courts across the country could mean increased difficulty challenging changes to environmental policy in the judicial system.

“We are anxious about what that really means in some of the more harmful decisions that the administration may make on climate or other issues,” Farooqi said.

Jenkins, too, said that the Conservation Law Foundation expects the fights it anticipates tackling to be more challenging this time.

But, despite city and state intentions to keep the needle moving on climate action, leaders said the reelection of Trump to the country’s top office is daunting.

“We have made progress [over the past four years], but in a moment where we really need to really lean in, we’re going to be dialing it back on the federal level,” she said.

Farooqi said he, too, worries that the new administration will be “extremely harmful” to the group’s work.

Top of mind for many groups locally is the impact Trump’s second presidency will have on environmental justice efforts.

Under the Biden administration, the federal government turned its sights to specifically addressing inequity in climate work through its Justice40 Initiative, which made a first-of-its-kind federal commitment to direct 40 percent of climate benefits to the communities that have seen less environmental investment and have borne the brunt of pollution and other harms.

“What does it look like if there’s potential of freeze on those investments? If there’s a rollback of those commitments?” Jenkins said. “I think there’s a real question of how much we are setting back communities by beginning to invest and then potentially fully leaning away from that.”

Many of the programs covered by the Justice40 initiative receive funding through the Inflation Reduction Act and would be at risk under Trump’s proposal to rollback unused funding from that legislation.

And Project 2025, the 900-plus-page vision created by the conservative think tank the Heritage Project, calls for stopping all grants to “advocacy groups.” Throughout the race for the White House, Trump denied connection to the plan, which was developed independently from his campaign, but a number of the individuals who developed the plan had connections to his first campaign or administration and many of its proposals have lined up with his proposed policies.

As with climate efforts generally, Swett said maintaining a focus on environmental justice will be up to more local levels of government — something Boston is prepared for.

“We’ve been focused on climate justice a lot longer than the federal government has been explicitly focused on it, and we’ll continue to do so,” he said.

One more glimmer of hope: eight years after Trump’s first presidency, local environmental and conservation advocates point to a changing industry landscape that might make pulling back from clean technology and other green efforts a harder sell on an economic level.

“It is a much more mature industry,” Swett said. “When you see the jobs and efficiencies and the technologies that are available now, we’re at a different place.”

Across the country, he said, green energy is increasingly cost-competitive in a lot of parts of the country.

“The initial supports to balance out what had been a highly subsidized oil and gas industry, to allow a level playing field where renewables could compete has largely worked,” Swett said.

While he said it won’t solve all the climate problems facing the United States, Farooqi said that accelerated landscape means that some of the action corporations are taking on climate change will continue unimpeded.

“I don’t want to be too Pollyannaish about corporations’ values here, but I do think that is a meaningful difference from what happened last time around,” Farooqi said. “I think it’s something that can be really helpful.”