The group now is chaired by Houston Mayor Sylvester Turner, whose administration recently began buying enough renewable energy to power all municipal operations and unveiled a Climate Action Plan last spring that aims for carbon neutrality by 2050.

“Cities are leading the way,” Turner said Sunday at an Earth Day celebration event downtown. “When we didn’t have a federal partner in the White House, cities took the lead. Thank God now we have a partner in the White House and we can do even more, and we can do it a lot quicker.”

Not every large city is approaching climate change with the same vigor, according to a survey of the 100 largest U.S. cities released last October by the nonpartisan Brookings Institution. The study found that 45 of the 100 cities had set specific greenhouse gas reduction targets based on current emission levels as of 2017, and about two-thirds of those cities were lagging behind their goals.

Turner has adopted a far more aggressive posture on climate change than previous Houston mayors, who generally have deferred to the interests of the city’s outsized oil and gas industry. In recent weeks, Turner repeatedly has disputed claims from Republicans about the role of wind energy in Texas’ February power outages.

This week, the mayor’s schedule includes an interview on climate change with NBC News anchor Lester Holt, which aired as part of Holt’s national show Monday evening, and a climate-focused virtual event with White House officials and other mayors on Tuesday.

“We're often kind of hungry for leadership on the environment in Texas, and he's one that's really stood out as somebody that cares deeply about this and wants to see results and is willing to pick the big battles that we need to make progress,” said Luke Metzger, executive director of the research and advocacy group Environment Texas.

Turner also has received criticism from environmental activists who argue city leaders are relying too much on the input of oil and gas companies as they develop plans to reduce Houston’s carbon footprint. As an example, they cite BP’s $2 million donation to support the city’s Climate Action Plan, and the company’s plan to make experts available to city officials and lead working groups that arise as part of the plan.

During Turner’s mayoral tenure, which began in 2016, multinational oil and gas companies with major presences in Houston — including BP, Shell and Total — have ramped up their investment in wind and solar power, energy storage and vehicle charging stations, and adopted emissions targets that mirror the city’s. Earlier this month, Shell threatened to leave major U.S. oil and gas trade groups if they did not support climate policies in line with the Paris climate agreement.

Lara Cottingham, the city’s chief sustainability officer and lead author of Houston’s Climate Action Plan, said city officials sought buy-in on the plan from the energy industry, along with local communities, because the city would have almost no authority to force businesses to follow the plan’s climate goals if they weren’t on board.

She said Turner seems more deeply involved in conversations about the future of the energy industry than city leaders elsewhere are for other types of industry.

“The city of Houston is home to the largest medical complex in the country, but Mayor Turner isn't called upon to make medical diagnoses or talk about COVID treatments other than how we get vaccines to people as quickly as possible,” Cottingham said. “But the mayor of Houston really is seen and really does have a role to play in this global energy industry.”

Metzger said he views Turner’s relationships with energy companies as a “point of strength,” because the mayor can push them to take stronger action on climate change. He said Houston overall has made steady progress on climate action under Turner, but still could adopt a number of other, immediate policies to further address the city’s longstanding air and water pollution issues.

Environment Texas issued recommendations last month for city leaders to expand the use of electric vehicles in various city departments and among METRO buses, and enact building codes and zoning ordinances that account for electric vehicle parking and charging stations, among other changes.

Last August, Houston City Council approved a handful of new ordinances aimed at making parts of the city more walkable and reducing residents’ reliance on cars, including measures that will bring buildings closer to the street, force parking lots to the side or behind buildings, expand sidewalks, and require buffer zones between sidewalks and the road.

City Hall also is seeking to add hundreds of electric charging stations on city-owned land, and has leased a 240-acre closed landfill in Sunnyside to a developer who plans to build a solar farm on the site.

“There's a lot cities can do, especially in Texas where our Legislature and state government are often hostile to climate action,” Metzger said.