(CNN) In 2019, the city council in Berkeley, California, held a stunning vote: it would ban natural gas hookups in all new building construction to reduce greenhouse gas emissions and the city's impact on the climate crisis.
No gas furnaces in new homes, the council said. No gas stoves or ovens.
Other progressive cities followed suit with similar bans. San Francisco passed its own ban in 2020. New York City became the largest US city to pass a version in 2021, with New York Gov. Kathy Hochul vowing to pass a statewide law that would ban natural gas by 2027.
But other municipalities looking to take similar action are running into a brick wall. Twenty states with GOP-controlled legislatures have passed so-called "preemption laws" that prohibit cities from banning natural gas.
It's bad news for municipal climate action: Taking natural gas out of the equation and switching to electric appliances is one of the most effective ways cities can tackle the climate crisis and lower their emissions, multiple experts told CNN.
"Natural gas bans are kind of low-hanging fruit," said Georgetown Law professor Sheila Foster, an environmental law expert. Foster said cities can make a significant impact by moving away from natural gas and toward electricity, especially considering what little federal action there's been on climate, and the mixed record of states.
The climate stakes are high. Residential and commercial emissions made up 13% of total US emissions in 2019, according to the Environmental Protection Agency. About 80% of those emissions came from the combustion of natural gas, the fuel that heats homes or powers a restaurant's cooking stoves, and emits planet-warming gases like methane and carbon dioxide in the process.
But clean alternatives exist: Electric heat pumps can heat homes more sustainably than gas furnaces; induction ranges can replace gas stoves. And experts stress that to fully transition to renewable energy sources like solar and wind, homes and businesses need to operate on electricity -- not gas.
President Joe Biden's Build Back Better bill, which fizzled in the Senate after objections from Sen. Joe Manchin of West Virginia, contained billions in tax incentives to help consumers switch to cleaner ways of heating their homes. But people who own and rent homes in big, multi-unit buildings depend on developers and city planners to make the switch.
Advocates worry these preemptive bills could stall impactful climate action at a critical time.
"We're afraid that's going to have a chilling effect on cities that want to take action," said Alejandra Mejia Cunningham, a building decarbonization advocate at the Natural Resources Defense Council. "Many cities and towns have small staffs, they don't want to be taken to court, being seen as going outside state law."
In November, a GOP bill to block natural gas bans in new buildings was passed in North Carolina but ultimately failed to make it into law when Democratic Gov. Roy Cooper vetoed it. Two more similar bills are being considered in Pennsylvania and Michigan this year.
"To me that's what's interesting about this new trend, it seems like states are trying to eliminate the possibility before cities try to catch onto this," Sarah Fox, an associate law professor at Northern Illinois University School of Law, told CNN. "The natural gas industry realized this was in the water a while ago and has been very aggressive in getting this passed."
The American Gas Association, the natural gas industry's powerful trade group, told CNN it lobbies at the federal level but isn't directly lobbying in any state.
But many of the association's members, including gas utilities, have gotten involved at the state level, according to an analysis by independent climate think tank InfluenceMap for CNN.
InfluenceMap "found high levels of engagement on preemption bills within the power sector, including its key trade associations." The American Gas Association and its members "appears to have played an early role encouraging these bills," according to the analysis.
There's also evidence that suggests the AGA is running the playbook for its members to lobby state lawmakers for the preemptive laws.
In audio of a private AGA call obtained by watchdog group Energy and Policy Institute and shared with CNN, the AGA's Vice President of Advocacy and Outreach Sue Forrester discussed the group's strategy modeling "preemptive legislation" in certain states.
"We launched in partnership with Southwest [Gas]. Well, they launched it, but we were helping on the back end: Energy choice language in Arizona that was passed and signed by the governor at the beginning of the year," Forrester said in the recording.
When asked about Forrester's comments, an American Gas Association spokesperson reiterated the trade association doesn't get involved in state-level legislation.
"Sue's comments make it sound that way, and that's unfortunate, but the American Gas Association is not set up with lobbyists on the ground in the states," the spokesperson said, adding the "we" Forrester was referring to is "we as the industry and all who have an interest in gas."
CEO of the American Gas Association Karen Harbert told CNN in a statement that "AGA is educating policymakers at every level about the supportive policy frameworks necessary for natural gas and our infrastructure to help achieve our nation's ambitious environmental goals."
While the AGA and other industry groups are messaging that they are advocating for more fuel choices for consumers, climate advocates say the preemption laws are having the opposite effect.
"I'd say the industry has put decades of effort and resources into fine tuning their messaging to the American public -- and they do it well," NRDC's Mejia Cunningham told CNN.
Most cities and towns in the US that are pursuing natural gas reforms are not shooting for stringent bans like what Berkeley passed -- many are trying to find a middle ground that incorporate and encourage electrification and heat pumps as an alternative to gas.
Broadly written state laws can discourage that transition, Mejia Cunningham said.
"We don't expect Berkeley to be the right model for most of America," she said. "That doesn't mean we should completely slash out a whole bucket of policies that could work for communities across America."
In 2019, officials in Flagstaff, Arizona, were working on their city's plan to get to net-zero emissions by 2030. Building emissions were an obvious target; the built environment is the largest contributor to Flagstaff's greenhouse gas emissions, Nicole Antonopoulos, Flagstaff's sustainability director, told CNN.
Flagstaff's plan didn't include an explicit ban on natural gas; instead, it said the city would promote "aggressive building electrification," thereby decreasing reliance on fossil fuels.
That was still enough to get the attention of members of the Republican-controlled Arizona state legislature, which in 2020 passed a bill preventing cities and towns from passing their own natural gas bans.
"It was a huge setback, in a nutshell," Antonopoulos told CNN. "The state preemption threw a huge kink in our efforts towards carbon neutrality. This isn't the first time the state has preempted things that have made us go back to the proverbial drawing table and figure out how we get creative and innovative in a space where we don't have funding."
Arizona's 2020 law -- the first natural gas preemption law of its kind -- was a harbinger of what was to come. Since then, 19 other states have adopted them. These laws have largely been concentrated in red states in the Rust Belt and Southwest, a cluster of southwestern states including Utah and Wyoming, and New Hampshire.
And currently, there's not much favoring cities' ability to sue states. The 1907 US Supreme Court case Hunter v. Pittsburgh favored states' authority to craft laws for their cities, and gave cities little legal recourse to sue.
"It's not a very coherent line of case law, but that's the official stance," said Fox, who added she'd be very surprised if the current conservative Supreme Court majority allowed a challenge to the current law from progressive cities.
"There's a lot of legal uncertainty," Foster said, adding that there's not much current litigation to speak of around natural gas bans and preemption laws.
In Flagstaff, Antonopoulos said her office is trying to find ways around Arizona's law. It's meant a lot of active outreach to local developers building in Flagstaff, encouraging them to build all-electric housing developments. It's also reaching out to residents whose gas appliances are at the end of their lifecycles to consider buying electric.
"Our challenge here is we have a 2030 deadline" to get to net-zero, Antonopoulos told CNN. "The urgency is so great so sometimes we don't have that luxury in time."
CORRECTION: This story has been updated to correct that Mejia Cunningham was speaking on behalf of the Natural Resources Defense Council.