While we’re far from perfect, we’ve been able to conclusively demonstrate that it’s not just feasible but beneficial to decarbonize the fifth largest economy in the world: take a look at the chart below. That’s a big deal.

One agency, the California Air Resources Board, or CARB, is particularly critical in the mission to equitably decarbonize California. The agency supervises greenhouse gas (GHG) emission reductions from our two biggest sources of carbon pollution: the cars, trucks, and other vehicles that move people and goods around the state, and the industrial activities that keep our economy thriving. CARB has paved the way for California’s clean vehicle revolution through a complex suite of regulations, such as its Advanced Clean Cars Program. Let’s Green CA! Is working to make those programs more accessible to low- and moderate-income families through legislation (click the link to learn more about SB 1230).

Now, a recent update to CARB’s clean cars program would chart a path to phasing out all gas-powered car and truck sales by 2035. This may seem like an ambitious goal given the 29+ million cars currently on California’s streets and highways, but the latest climate reports have made it crystal clear: we need to move as quickly as possible to a low-carbon future to prevent calamity. That’s why Let’s Green CA! is urging CARB to move up its proposed deadline. We’re calling on CARB to ensure that 100% of the new vehicles sold in California are clean cars by 2030. You can join us by submitting a public comment to CARB stating just that: be sure to submit your comment before the May 31st deadline!

Why are we so focused on accelerating our transition to clean cars? Simple. California’s transportation system — all the cars, motorcycles, trucks, airplanes, ships, and industrial vehicles and fuels that move people and goods around — make up more than half of all of our greenhouse gas (GHG) emissions, and we simply can’t meet our state climate goals without switching to low-carbon modes of transportation as fast as we possibly can.

You can see in the figure below that direct tailpipe emissions from passenger cars and trucks make up just under 30% of all California’s GHG emissions; adding all the emissions resulting from the extraction, refinement, and shipping of the gas and diesel fuels that power those vehicles bumps up the total to close to 40% of all state emissions. This just so happens to be almost exactly the same amount of emissions that California needs to cut in order to meet our 2030 goal set by AB 32 (40% below 1990 levels by 2030). So all we need to do is phase out gas-powered cars and we’ll be set, right?

There’s one extra wrinkle: cars stay on the road for a long time. The average age of a car or truck in the United States is over a decade, with significantly older, more polluting models in lower-income neighborhoods. That means that any clean car sales target we set today will take years to create meaningful cuts in emissions, so the sooner we can get to 100% clean car sales the sooner we can get the last gas-powered cars off our roads.

To get an idea of how much faster a 2030 clean car sales goal could reduce our carbon emissions compared to CARB’s proposed 2035 mandate, I modeled out the impacts of these two deadlines on Zero Emission Vehicle (ZEV) adoption statewide under a range of market growth scenarios. You can see what I found in the figure below:

My modeling suggests that by accelerating our transition to clean cars by just five years, we can put about 20%, or six million, more ZEVs on the road over the next decade. Leaving aside further efficiency improvements in new gas-powered vehicles, California could prevent an additional 423 million metric tons of carbon dioxide equivalents over the next 15 years — saving 47.5 billion gallons of gasoline, or the same amount of energy it takes to power California’s 14 million homes for about four years. Not only will this decrease our reliance on foreign oil, it will put us closer both to reaching 100% ZEVs (by about three to four years) and our legally-mandated climate targets.

Now, putting millions of new cars on our roads over the next dozen years is no small feat, and there will undoubtedly be costs associated with going faster. But—there are also costs, dire, catastrophic costs—to not going fast enough. In my opinion as an environmental scientist and climate policy expert, we have reached the point where all climate actions should be implemented as soon as possible as the default. Those who are saying we have to go slower must have the burden of proof placed on them, because there is a mountain of proof that we need to act NOW on climate.

We have the technology, the experience, and the need for a speedy transition to ZEVs. Let’s make it happen! Please join me by telling CARB today: we need 100% clean cars by 2030!