The legacy auto industry is finally sending welcome signals that it’s serious about addressing climate change.

We saw it last week when General Motors CEO Mary Barra pledged her company would completely transition to zero-emission vehicles by 2035. And we saw it Tuesday when Toyota, Fiat Chrysler and other manufacturers dropped their support for a Trump-era lawsuit seeking to block California from setting more environmentally friendly fuel standards.

Whether it’s the turnover in the administration, President Joe Biden’s plan for tougher fuel standards and seriously addressing greenhouse gas emissions, or Bay Area-based electric-car producer Tesla leaving legacy manufacturers in the dust, other carmakers now seem to recognize the industry’s future lies in zero-emission vehicles.

But exactly how committed some of them are to changing their ways remains to be seen. As we saw during Trump’s reign, car manufacturers can easily shift direction with the political winds. They are often more concerned with preserving short-term profits than protecting the planet.

Not surprisingly, however, investors recognize the fallacy of short-term strategies. Which helps explain why Wall Street currently values Tesla at about 10 times that of GM. And undoubtedly nudged the latest round of carmaker flip-flopping in the aftermath of Biden’s election.

But as we saw with the showdown over California emission standards, the legacy auto industry divides between those committed to change and those that will have to be dragged along.

At issue was California’s federal waiver under the 1970 Clean Air Act allowing it to set tougher standards than those of the nation. Twelve other states and Washington, D.C., had federal authority to follow California’s lead.

As Trump moved to roll back Obama-era fuel regulations, he also tried to strip California of its authority to go it alone. When California and other states sued to protect the Golden State’s waiver, the auto industry split.

GM, Toyota, Fiat Chrysler and other manufacturers sided with Trump. Meanwhile, Ford, Honda, BMW, Volkswagen and Volvo cut a deal with California, agreeing to fuel standards that are much closer to those set by the Obama administration than those in the Trump mandate.

But soon after Biden won the presidential election, GM announced it was dropping its legal support of the Trump administration’s effort to gut California’s authority. Last week, the company followed with its announcement of its transition to a zero-emission fleet.

On Tuesday, Toyota, the newly formed Stellantis (which includes Fiat Chrysler), Subaru, Hyundai, Kia, Mazda, Mitsubishi and the National Automobile Dealers Association also dropped out of the legal fight against California. That sets the stage for the Biden administration to negotiate a fuel-standards deal based around California’s requirements.

Tougher fuel standards will be welcome. But the bigger issue is national elimination of fossil fuels in our vehicles. When car manufacturers make binding pledges to that we’ll know they’re really committed to fighting climate change.