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California will phase out the sale of new gasoline cars by 2035 under a stringent new rule adopted by state regulators Thursday. The policy marks a historic moment for the Golden State and the nation, with potential global implications for the fight to rein in greenhouse gas emissions from the transportation sector, which experts have long said are some of the hardest to address.

The new rule, which is the first of its kind in the United States and is the strictest among just a handful of similar bans around the world, will be implemented in phases. It requires 35 percent of the available passenger vehicle models offered by auto retailers in the state to be electric or hydrogen gas-powered by 2026, with that proportion increasing to 51 percent by 2028, 68 percent by 2030 and ultimately to 100 percent by 2035. The plan also outlines a goal of having all medium- and heavy-duty vehicles be zero-emission by 2045.

“This is monumental,” Daniel Sperling of the California Air Resources Board, the regulatory body that approved Thursday’s measure, told CNN. “This is the most important thing that CARB has done in the last 30 years. It’s important not just for California, but it’s important for the country and the world.”

That’s a sentiment being shared among many environmentalists and climate activists. Not only is the policy expected to reduce California’s tailpipe emissions by as much as half through 2040, with many other states likely to follow suit, but it tackles a source of emissions that policymakers have especially struggled to grapple with for decades.

Transportation is the leading single-sector source of greenhouse gas emissions in much of the world. It makes up 21 percent of global carbon emissions, 29 percent of U.S. emissions and a whopping 50 percent of California’s emissions. Those numbers have made transportation a top priority for many climate-conscious policymakers, but the sector has remained notoriously difficult to manage for a number of reasons.

One issue is that compared to other major emitting sectors, transportation is made up of an especially diverse body of emission sources. In the power sector, for example, states have made substantial progress reducing emissions by focusing on a few major regional producers and forcing them to limit their carbon footprint through clean energy mandates, cap-and-trade initiatives and targeted investments. Targeting coal plants is a prime example of how the U.S. has been able to drastically reduce the power sector’s greenhouse gas emissions, despite the nation’s growing demand for electricity over the years.

But experts have noted that officials have fewer options and far more to consider when it comes to tackling transportation, which is largely made up of a menagerie of different consumer, commercial and government vehicles, all with different carbon footprints and operated by people with different needs, behaviors and desires. The majority of the sector’s emissions, about 59 percent, come from cars and other passenger vehicles, according to the Environmental Protection Agency, while airplanes, ships, trains and other sources account for 18 percent.

The result has been a kind of diaspora of solutions—a mixed bag of approaches with no central scheme to figuratively call home—that impact different people and industries inconsistently, often complicating the consensus process and slowing down progress. So while many governments, including California and the Biden administration, have made progress on implementing new rules to shift public vehicles to low-emission or zero carbon vehicles, the process has been far more difficult when it comes to the more diverse private sector. For example, automakers based out of state or located overseas are often outside the jurisdiction of governments—another major difference between transportation and the power sector, which has far more federal oversight.

Transportation is also deeply engraved in culture and the demand for it is closely tied to economic growth, personal status and a sense of entitlement to the status quo, Christian Brand, an associate professor of transportation, energy and environmental studies at the University of Oxford, said in a recent opinion essay.

“Many people are reluctant to give up their car or flying, feeling that it is an infringement of their rights,” Brand wrote in the op-ed. “Efforts to decarbonise transport are being hindered by a cultural attachment to the polluting status quo, which isn’t as present in other sectors.”

Those factors help explain why U.S. power sector emissions have fallen while transportation emissions continue to rise. Between 2005 and 2017, the nation’s power sector emissions fell 28 percent, according to the U.S. Energy Information Administration. Tailpipe emissions, on the other hand, rose from 2012 to 2018, says the EPA, with transportation emissions surpassing that of the power sector for the first time in 2016.

California’s new regulation helps to address many of those issues. It groups all future passenger vehicles together under one banner, albeit medium- and heavy-duty trucks come at a later date. It passed with broad support from the auto manufacturing industry, given major companies have had ample time to prepare for it and public opinion had already swayed most of the major automakers. And the way the ban is being implemented helps to ease consumers into the new reality without necessarily making it appear like it’s being forced on them.

California’s policy doesn’t outright ban all gasoline cars, it just limits how many new ones can be sold by retailers by certain dates. Even after 2035, when all new sales must be carbon free, people can keep their existing gasoline cars or buy used ones, and 20 percent of sales can be plug-in hybrids that run on batteries and gas.

Furthermore, because transportation plays such an outsized role in polluting low-income neighborhoods and communities of color, California’s new rule also has broad support from the environmental justice community and health officials, although some activists say they believe the rule should have gone further. Most transportation hubs and major highways cut through or near some of the nation’s most vulnerable communities, disproportionately exposing them to air pollution and exacerbating health conditions like lung disease, asthma and the risk of premature death.

California officials have also promised to find ways, including taking full advantage of federal money available in the Inflation Reduction Act, to make electric vehicles more affordable for low-income buyers. While EVs are believed to save consumers money in the long run because of lower cost for maintenance and fuel, they still cost far more upfront than their gasoline counterparts, on average.

Liza Gross, who covers agriculture and other environmental and social justice issues in California for Inside Climate News, said the new rule will likely have a rippling effect throughout the country. The Golden State has long been considered a bellwether when it comes to environmental, climate and other regulatory policies—especially regarding auto emissions standards and air pollution.

With more than 39 million residents and 10 percent of the U.S. auto market, California is by far the most populous state and often influences the U.S. market and national politics in outsized ways. Congress even granted California special authority decades ago to set its own vehicle emissions standards that are stricter than the federal ones, a move that has since been adopted by more than a dozen other states.

“That’s what happened when California passed a new rule saying furniture could meet fire safety standards without adding toxic flame retardant chemicals,” Gross told me. “The rule effectively created a national market for chemical-free furniture. I could imagine the gasoline ban doing the same thing for cars.”

That’s it this week for Today’s Climate. Thanks for reading, and I’ll be back in your inbox on Tuesday.

That’s how much money was invested in renewable energy worldwide during the first half of the year, setting an all-time global record with an 11 percent rise over the same time period last year, according to new data from BloombergNEF.

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