Maryland’s most populous jurisdiction is promising an ambitious package of new climate initiatives in 2020, joining other liberal counties, cities and states stepping up to address what they see as the Trump administration’s resistance to protecting the planet.

With earthquakes and warming temperatures wreaking havoc across the world, and President Trump rolling back emissions limits and withdrawing from the Paris agreement, officials in Montgomery County are determined to accelerate their own efforts to counter climate change.

They want to mandate solar panels on new homes, make electric buses commonplace and force commercial builders to improve energy efficiency. Many new laws and policies will be announced in the next two months, said Adriana Hochberg, climate change coordinator for the heavily Democratic suburb of 1 million people just outside Washington.

In February, Montgomery will hold a town hall on hundreds of recommendations from climate workgroups convened last year by County Executive Marc Elrich (D). And by early 2021, officials hope to unveil a comprehensive plan detailing how the county will reduce greenhouse gas emissions by 80 percent by 2027 and 100 percent by 2035.

Environmental activists say these steps are long overdue. But builders and developers warn that additional regulations could increase operating costs in Montgomery, exacerbating an affordable housing crisis and chilling business development in a suburb that has lagged behind its neighbors in economic growth.

“Montgomery County already has stringent building codes,” said Lori Graf, chief executive of the Maryland Building Industry Association. “Added regulations — it’s just going to make it more difficult to operate.”

Hochberg, echoing most of the 2020 Democratic presidential candidates, said the county cannot afford to wait: “Given that the world is on fire — literally,” she said, referencing the raging wildfires in Australia, “we need to take action.”

“Nobody should be under any illusions,” said County Council Vice President Tom Hucker (D-District 5), who chairs the environment committee. “County leadership is completely committed to this.”

Among the county’s biggest planned proposals is a set of “Building Energy Performance Standards,” which will legally require buildings over a certain size to improve energy efficiency over a period of time. Both the District and New York City included similar standards in recent climate legislation.

Hucker said he plans to introduce the standards to the council this spring, along with a bill to expand the county’s Benchmarking Law, which requires commercial buildings to monitor and report their energy use to the county annually.

Officials are also weighing measures that could affect homeowners.

Chris Fang Brehm, an environmental consultant who participated in the climate workgroups, said he was impressed that the county is considering “Passive House” — a model of energy efficiency that strives to dramatically reduce the need for space heating or cooling through “passive design,” such as windows oriented to maximize exposure to sunlight. The concept has roots in Europe and is not yet widespread in the United States, Fang Brehm said.

The county is also drafting a bill requiring that all new single-family houses include rooftop solar panels, Hochberg said.

The controversial mandate, which just took effect in California, worried builders when Elrich raised it in September. Additional regulations, such as new energy performance rules or more stringent building codes, could push some businesses out of the county entirely, Graf said.

“We have competing jurisdictions here. . . . A lot of our builders, specifically those who have built in Northern Virginia, are just not interested in building in Montgomery at this point,” she said.

Charles Nulson, president of the Washington Property Company, which has properties in Montgomery and Fairfax counties, said he knows of several property owners that have already reduced operations in Montgomery because of its “unwelcoming culture” to businesses. He agreed that more regulations could worsen the county’s business image.

Andrew Friedson (D-District 1), who has built a reputation as an ally to the business community on the all-Democratic council, said he prefers to wait until the new policies have been formally introduced before assessing them. In general, however, he said he does not think Montgomery can achieve its climate goals with “a heavy-handed, top-down approach.”

“We shouldn’t be too quick to introduce new laws,” Friedson added. “We need to focus first and foremost on what we have that works.”

Graf said new requirements on home builders could also have the unintended effect of raising housing costs at a time when Montgomery and the Washington region are supposed to be addressing a significant shortfall of affordable housing. According to a 2019 report from the Urban Institute, Montgomery needs to build 23,100 additional low-cost housing units by 2030 — the most of any jurisdiction in the area.

Hochberg said the county is looking closely at possible repercussions on affordable housing, but will not be deterred by the opposition of builders and developers.

“If we don’t more aggressively retrofit our economy now,” Hucker said, “our development will only suffer in the future.”

In Montgomery, as in cities and suburbs across the country, this debate over the pace of change is likely to intensify as scientists ring the alarms on a worsening “climate emergency.” While business leaders worry that too much is happening too quickly, activists, such as Montgomery’s Jim Driscoll, say the existing proposals amount to “baby steps.”

“Marc Elrich, the county government and the County Council are gumming us to death,” said Driscoll, an Extinction Rebellion member who was arrested in 2019 for protesting outside county government headquarters in Rockville.

“It’s obvious what needs to be done,” he added gruffly. “[But] it’s not like they’re taking a big bite.”