If only Texas could go back to the future.

To a time when elected leaders and policy makers addressed global warming and air pollution, and saw renewable energy as an opportunity to improve the environment and economy.

To a time when lawmakers set audacious goals — to produce twice as much wind power as the nation — and jump-started a free market that blew past the mandates.

To a time when Texas was the pioneer in energy efficiency and two dozen states followed the example.

That was the late 1990s, when Texas was leading on clean energy, not lobbying or litigating against every environmental idea out of Washington or California or Paris.

“I’m so proud of Texas,” said Jim Marston of the Environmental Defense Fund, who’s been working on clean energy issues for three decades. “Now, it just breaks my heart.”

After President Donald Trump rejected the Paris climate accord this month, at least nine states and hundreds of mayors and businesses vowed to keep working toward the goals.

Not Texas.

Blame it on polarization, the Koch brothers, the revival of oil and gas or the rejection of science and elites that Trump has championed. Whatever the reason, today's Texas is nothing like the Texas of 20 years ago, when people could agree on inconvenient facts and hammer out ambitious ways to confront them.

Two U.S. senators and a Texas Railroad commissioner hailed Trump's decision, and the state's top elected officials have been climate change skeptics. Perhaps the best indicator of the state's environmental policy is the attorney general's office: Since 2010, Texas has filed 27 lawsuits against the U.S. over climate change and air and water quality, according to the Texas Tribune.

The urgency about the climate starts with melting ice caps, rising seas and extreme weather. But there’s also a market opportunity, especially for innovators. Almost 200 countries signed the Paris accord, and they’re looking for cleaner ways to fuel development.

The challenge is reminiscent of the late 1990s, when air pollution posed serious health threats in Houston and Dallas. At the time, many state leaders accepted the risk of global warming, along with fears that oil and gas production had peaked in Texas.

The state convened a panel to study the issues and map out a strategy. That included pulling in experts from utilities, the energy industry, research universities, consumer groups, government agencies and conservation.

The result was a 1995 report titled: “Texas Energy for a New Century.”

“Texas is the first state with the foresight to produce a strategic plan for systematic integration of renewable energy and energy-efficiency practices into energy development, production and use,” wrote Texas Land Commissioner Garry Mauro.

The report concluded that Texas was poised to make a transition to renewable resources and energy efficiency. They could “provide both environmental and economic benefits, and maintain for Texas its position as a world energy leader,” the report said.

The project started under a Democratic governor, Ann Richards, and key principles were adopted under two Republicans, George W. Bush and Rick Perry. In 1999, Texas deregulated the electric market, and lawmakers passed standards for energy efficiency and renewables.

Marston said officials wanted to double the amount of utility-scale wind power in the U.S., so the Legislature set a goal of adding 2,000 megawatts of renewable power.

“That’s Texas leading,” Marston said. “We believed that economies of scale would drive down the costs and improve generation.”

The state surpassed the target early, so lawmakers doubled the goal again — and that was topped early, too. Today, Texas generates the most wind power in the nation, and its success contributed to the sector’s growth around the world.

In 2005, lawmakers passed a bill that led to construction of about 3,600 miles of new transmission, known as the Competitive Renewable Energy Zones. The CREZ lines, which cost nearly $7 billion, have been bringing cheap wind power from West Texas, lowering the price of electricity and helping the environment.

“People think Texas has all this clean energy and no mandates, and that’s completely untrue,” Marston said. “A bunch of important policies jump-started this market.”

Texas was the first to use a free-market approach to efficiency, said Neal Elliott, an adviser to the 1990s energy panel. Texas set the targets and let the market figure out how to meet them.

“That’s a very Texas thing,” said Elliott, senior research director at the American Council for an Energy-Efficient Economy in Washington.

But the state didn't build on the early lead. In 2007, it ranked 11th in efficiency, according to the group's annual rankings. Three years later, it dropped to 32nd after lawmakers excluded big industrial companies from the program.

Twenty-five states followed the Texas approach, he said, but all have set higher targets. Even Arkansas’ standard is much more ambitious.

The backsliding is hard for Tom Smith to accept. The former director of Public Citizen in Austin, “Smitty” was a member of the sustainability panel that produced the 1995 strategic plan. He compares that effort with breakthroughs in agriculture and transportation planning that set Texas on a more progressive path.

Smitty spent years lobbying lawmakers to support renewable energy and the CREZ lines. One of his favorite professional memories is from a groundbreaking ceremony for a wind farm in rural Texas.

He stood next to a staunchly conservative lawmaker, who couldn’t believe he was thanking Smitty, a Texas liberal icon, for helping bring economic development to his district.

Those were the days.

“What’s changed the most?” Smitty said about the current state of affairs. “The lack of visionary Republican leadership.”