With the Trump administration’s announcement Monday that it will roll back the nation’s fuel-efficiency targets and might try to force California to do the same, car consumers who care about slowing global warming should prepare to vote with their pocketbooks.

Bay Area Rep. Mark DeSaulnier has called for a boycott of companies that fail to meet the tougher Obama-era targets that the president is abandoning. Here’s another way to put it: Californians, and indeed all Americans, should only support car manufacturers that balk at Trump’s rollback and adhere to the stricter standards.

The outgoing standards would have required a nationwide boost for new passenger cars and light trucks to an average fuel economy of 54.5 miles per gallon by 2025. That’s about 40 mpg in real-world driving.

Clearly, the president has no interest in fighting climate change, nor has he even acknowledged scientific evidence that the problem is real and critical. If his administration won’t enforce the tougher fuel-economy standards, then environmentally conscience consumers must use their purchasing power to do so.

The Trump administration is also considering whether to try to take away California’s ability to stick with the tougher standards, which were hammered out in 2012 between the Obama administration, auto manufacturers and this state’s air regulators.

California, which for half a century has led the way on fighting air pollution, plans to try to stick with its current rules. The state was part of the negotiations for the Obama-era standards because it has a federal waiver under the 1970 Clean Air Act allowing it to set tougher standards than the nation.

Twelve other states and Washington, D.C., have federal authority to follow California’s lead. Consequently, California’s standards cover nearly 35 percent of cars sold in the United States.

State Attorney General Xavier Becerra says he will fight to maintain the tougher standards in California. The state and environmental groups may or may not prevail in what is sure to be a lengthy political and legal battle to stop Trump’s move.

In the meantime, consumers should send a loud message that those carmakers that continue to meet the Obama-era agreement will be rewarded.

Some auto manufacturers claim they’re not interested in rolling back the tougher standards, but their trade organizations have been sending a different message that those targets would undermine carmakers’ ability to meet consumer demand.

They say that low gas prices are driving high demand for trucks and SUVs over more fuel-efficient vehicles. The notion that auto manufacturers are helpless to meet the tougher targets is bogus. Automakers can, and should, solve this by adjusting vehicle prices to steer demand away from gas guzzlers.