For decades, government pressure has been needed to force U.S. automakers to agree to reduce pollution and CO2 emissions from their fleets. Now, with the Trump administration, the job of pushing Detroit to cut emissions falls to California and other environmentally minded states.

When General Motors CEO Mary Barra recently affirmed a commitment to “a world with zero crashes, zero emissions, and zero congestion,” she echoed similar statements from the company’s executives over the years. Back in 1972, GM Vice President Elliott Estes had declared that “the automobile will be essentially removed from the air pollution problem in the United States” within another decade or so. That didn’t happen, yet two decades later President Bill Clinton played along with this fantasy. Bowing to the power of GM and its then-Big Three partners, Ford and Chrysler, Clinton broke a campaign pledge to raise Corporate Average Fuel Economy (CAFE) standards and instead underwrote industry research on super-clean future cars. Meanwhile, fuel economy fell while CO2 emissions continued to rise. U.S. automakers have always been reluctant partners in the nation’s efforts to reduce air pollution and improve fuel efficiency. Today, Detroit is seeking to undo the carbon-cutting fuel efficiency targets agreed to during the Obama administration, again offering the false promise of green breakthroughs tomorrow. This time, however, it’s happening with the help of an administration and a ruling party openly hostile to the environment. Like some other industries, automakers have been cultivating such a political moment for years. They seized it in 2016 when Donald Trump was elected, writing his transition team two days after the election to request a new review of the vehicle fuel efficiency standards that had been painstakingly developed just a few years earlier. After Trump took office, his new head of the Environmental Protection Agency, Scott Pruitt, agreed to the automakers’ request, officially negating the Obama administration’s 11th-hour determination that the existing strong standards should stand.

Lack of technology has never been the limiting factor for making progress to protect the environment.

Regulations are necessary to mitigate greenhouse gas (GHG) emissions, just as they were for reducing smog. Lack of technology is not now, and never has been, the limiting factor for making measurable progress to protect the environment. The obstacle is lack of political will. And with the political will to cut greenhouse gas emissions utterly lacking in the nation’s GOP-ruled capital, hope now rests on California and other allied states committed to steady progress on emissions reduction. Although closely coupled, automotive fuel economy and CO2 emissions are regulated separately under the law. It took several years of discussion to develop the coordinated California and federal greenhouse gas emission rules that the Obama Administration finalized in 2012. These standards call for new fleet greenhouse gas reductions and a parallel improvement in fuel economy standards averaging more than 4 percent per year by 2025. Many forms of regulatory flexibility are built into the standards, so that the actual efficiency levels will be lower than those nominal targets even if the rules are not weakened. Nevertheless, these standards assure steady reductions in CO2 emissions — an important step in fighting climate change considering that transportation accounts for 28 percent of the country’s total annual greenhouse gas emissions of 6.5 billion tons of CO2 equivalent.

California, which accounts for 13 percent of the U.S. auto market, has played a key role in pushing for stricter pollution and fuel efficiency standards. Justin Sullivan/Getty

Joined by 16 other states, California sued the Trump Administration last month over its decision that the standards need to be weakened. The state’s leadership is a key reason why the nation has made historical progress on clean air, with California leading the fight decades ago to slash vehicular pollution. And given that California accounts for 13 percent of the U.S.’s 113 million registered automobiles, Detroit must make vehicles that meet the state’s stricter pollution standards. Eliminating California’s authority to set greenhouse gas emission standards is on the auto industry’s hit list and is part of the assault on the standards scripted for its allies in the Trump administration. A proposal to remove California’s authority was in the administration’s draft rule that was flagged by Senator Carper. The purpose of regulation is to balance public health and safety against market forces that neglect such broader environmental and social costs. When gasoline prices moderate or drivers adapt to a higher price, consumers favor larger and faster cars and trucks with all manner of other features. There’s nothing wrong with such niceties, but they are no excuse for relaxing regulations. Achieving such a balance with motor vehicles is an important — indeed, iconic — aspect of the broader need for society to embrace an ethic of sustainable consumption. That doesn’t mean “crawling back into a cave” or “making everyone drive small cars,” as some car companies and their anti-civil society surrogates suggest. But it does mean using standards to guide automakers’ next rounds of redesign to prioritize fuel economy rather than more of everything else.

Weak consumer interest in the fuel economy gains needed to cut CO2 emissions is a problem.

The regulations that cut smog-causing tailpipe pollution were applied one step at a time in decade-scale phases. That approach gave engineers the lead time needed to progressively curtail emissions at minimal cost. We now have ultra-low emission gasoline vehicles, slashing tailpipe pollution to miniscule levels. The catalytic converter is a silver bullet in this regard, a technological fix that enables even the largest SUVs to be smog-free.

An important aspect of the current challenge is that there is no catalytic converter for CO2. Electric vehicles do greatly reduce net emissions, but their costs and capability limitations mean that electrification is no silver bullet. Progress on greenhouse emissions requires engineering cars and trucks for greater efficiency one step at a time across the entire market. Because fuel economy is a design issue that involves the whole vehicle, that effort competes with other features, including speediness, size, and other amenities favored by U.S. consumers. One facet of automakers’ complaints therefore rings true: weak consumer interest in the ongoing fuel economy gains needed to cut carbon emissions is a legitimate problem. Higher fuel efficiency standards require automakers to make trade-offs when they design the upcoming models of their cars and trucks, forcing them to forego new customer-pleasing features in order to engineer higher fuel economy while staying within budget.

A missing link in the car/climate solution is an effort to nudge consumers into considering environmental factors when they purchase a vehicle.

Unfortunately, little effort has been made to tackle a problem that thwarts the greening of the automotive sector: connecting the personal environmental concerns of consumers — which are widespread even if not ubiquitous — to their automotive decision making. The consumer taste issue will only become more acute as ever-more stringent CO2 limits are needed to stave off the most disruptive impacts of climate change. Therefore, a missing link in the car/climate solution is a broad-based effort to nudge consumers into considering environmental factors when they purchase a vehicle. A mainstream initiative along these lines might empower many more consumers than the narrow focus on EVs, which are a hard sell for many good reasons related to cost and convenience. Consumers can act on their ethics in small ways that don’t require significantly higher costs and major inconvenience. Think of the success of the anti-littering campaign of a generation ago and the high levels of participation that many communities see in recycling programs. Among cars, SUVs, vans, and pickup trucks of any size, type, and price range, some options are more fuel efficient than others, often with little cost difference and even a price savings. Encouraging consumers to consider everyday vehicle choices that are 5 to 10 percent more fuel efficient than versions that, say, feature higher horsepower, could add up to significant emission reductions across the mass market. Such a campaign would also help address the problem of consumer disinterest that confronts automakers as they face stronger standards.