WASHINGTON — Four Arizona Democrats have signed on as co-sponsors of ambitious legislation that would commit the United States to achieve a 100% clean energy economy by 2050.

The bill would require economy-wide net-zero greenhouse gas emissions and would also direct federal agencies to draft plans to clamp down on emissions that contribute to climate change. The Arizona Democrats are among the more than 150 Democratic co-sponsors to the bill, which was introduced this week by Rep. Don McEachin (D-Va.) and has the backing of national environmental groups.

The Arizona co-sponsors are Reps. Ruben Gallego, Raúl Grijalva, Ann Kirkpatrick and Greg Stanton. The other Democrat in Arizona’s delegation to the U.S. House, Rep. Tom O’Halleran, did not join as a co-sponsor, but a spokeswoman said he supports its goals and wants to see steps taken toward a clean-energy economy.

No Republicans, including the four from Arizona, are co-sponsoring the legislation.

Kirkpatrick said climate change “is the greatest threat we face,” and it has put Arizonans at danger of floods and wildfires. 

“I am sponsoring this legislation because I know that Arizona can be part of the solution to the climate crisis,” she said in a written statement. “The 100% Clean Economy Act is ambitious and achievable. This is the climate action that we need to bolster our economy, protect the health of our kids, strengthen national security, and usher our country towards a 100% clean future.”

Stanton said during his time as Phoenix mayor, the city prioritized clean energy and set its own ambitious goal to become carbon neutral.

“Climate change is ravaging the Southwest, and Congress has an obligation to take bold action to combat it,” he said in a written statement.

O’Halleran spokeswoman Kaitlin Hooker said the Sedona Democrat “applauds the intent of this bill as a broad framework for achieving carbon emissions reductions,” but wants to ensure that workers are protected as the country transitions to clean energy.

“He is focused on ensuring that this legislative package includes efforts to provide job and skills training and economic development resources to displaced workers and closing businesses like those he has outlined within his PROMISE Act, legislation to address the closure of NGS and similar plants,” Hooker said.

McEachin, the bill’s sponsor, said his legislation will protect Americans.

“The need to act on climate has never been clearer: 2019 is on pace to be one of the hottest years ever recorded and every week brings another community damaged by extreme weather events fueled by climate change,” said McEachin said in a statement. 

The bill, titled the 100% Clean Economy Act of 2019, “will protect public health and our environment; create high-quality green jobs that will strengthen our economy; and mitigate the impacts of climate change for all communities and all generations,” he said. 

Michael Brune, executive director of the Sierra Club, said the bill “presents an opportunity to tackle the climate crisis while providing federal leadership towards the creation of a new energy system.”

A major United Nations report released last year said the world could face catastrophic climate change impacts unless global greenhouse gas emissions are cut by 45 percent by 2030. The world would need to achieve net-zero emissions by 2050, the report found. 

The targets in McEachin’s proposal are less ambitious than the Green New Deal, a proposal championed by U.S. Rep. Alexandria Ocasio-Cortez (D-N.Y.) and U.S. Sen. Bernie Sanders (I-Vt.) that aims to transition the United States to 100% renewable energy by 2030. 

McEachin, who isn’t a co-sponsor of the Green New Deal, called that legislation “aspirational,” noting that it lays out broad goals but doesn’t articulate a path forward. 

His bill, he said, “is still ambitious and it’s very consistent with what scientists tell us we have to achieve.” 

The bill is one of several major pieces of climate change efforts introduced in the House since Democrats took control of the chamber in January. But while some of those efforts could clear the House this Congress, they’re unlikely to get traction in the GOP-controlled Senate.