As of March 2023, global temperatures are 1.1 degrees Celsius above preindustrial times. When temperatures rise, so does the concentration of CO2 in the air. The Earth has not seen CO2 concentrations this high in 3 to 5 million years. A United Nations report on climate change shows that the world, including the United States, is nowhere near the scale and pace of emission reductions required to keep the world from limiting global temperature rise to 1.5 degrees Celsius.

The Congressional Budget Office (CBO) published a report on transportation sector emissions in December of 2022. The largest source of emissions of carbon dioxide (CO2, the most common greenhouse gas) in the United States is the transportation sector. This sector is responsible for 38% of all CO2 emissions, the next largest industrial sector – electric power generation – accounted for 33%. And the transportation sector can’t make sufficient progress, even if the nation moves totally to electric vehicles, unless the electric sector also makes progress by dramatically reducing the amount of electricity produced by natural gas and coal.

Most emissions in the transportation sector come from cars and trucks. Motor vehicles accounted for 83% of CO2 emissions from transportation in 2019. Personal vehicles and commercial trucks averaged more CO2 emissions per passenger-mile or ton-mile than ocean, barge, rail, and the transmission of liquids by pipelines. The only mode with higher emissions than cars and trucks is air transportation.

According to the CBO, “reducing emissions from transportation has been difficult because of the value that people place on transportation and the dominance of a single fuel source—petroleum. Demand for transportation is much less sensitive to price changes than is demand for electric power, and people have had few cost-effective alternatives to motor fuels.”

The transport sector has made progress. In 2021, CO2 emissions in the transportation sector were 6% less than they were in 2005. The decline in emissions from transportation has contributed to a drop of about 20% in total carbon dioxide emissions in the United States since 2005. “CO2 emissions have declined since 2005—despite an increase in travel by car and truck—because vehicles have become more efficient.”

Tighter standards for fuel economy and emissions, along with greater use of electric vehicles, are projected to reduce emissions over the next decade. But only moderately. The CBO projects that CO2 emissions in the transportation sector to decrease by 9% from 2021 to 2032 as the vehicle fleet becomes increasingly efficient to comply with more stringent fuel economy standards. Sales of electric vehicles, which accounted for 4 percent of the market in 2021, are expected to grow substantially. The use of electric vehicles will contribute to greater emission reductions in future decades than it does today because the electric power sector will also continue to become progressively less carbon intensive.

However, there are limits to what the electric power sector can achieve in terms of carbon emission reductions. In a report published in ARC Insights, Gaven Simon pointed out that the electrification of the transportation (and building sector) will lead to increased demand for electricity. During peak hours when renewables cannot meet the demand, a “balancing” resource will need to be added. For example, if a region has a 3 day downturn in production from wind and solar, natural gas needs to be added to make up for the loss of production. This just-in-case energy source will make electricity more expensive.

Legislation is clearly needed to reduce emissions from the transportation sector. California, which leads other states when it comes to climate regulations, established a year-by-year roadmap which requires that by 2035 100% of new cars and light trucks sold in California will be zero-emission vehicles. Seventeen states have vehicle emission standards tied to rules established in California. These states face politically fraught decisions on whether to follow California’s strictest-in-the nation regulations. These are, for the most part, states largely controlled by Democrats. States controlled by Republicans are in no hurry to follow California’s lead.

Politicians are elected by the people, and Americans with lower incomes will be more impacted by the energy transition. But progress is being made. According to Kelley Blue Book, the average price of a new car in April was over $48,000. The average price of an electric vehicle (EV) was significantly more, $56,000. The good news for the environment is that new electrical vehicle pricing has fallen significantly; down by $11,000 compared to one year ago. It can be expensive to replace an electric battery – up to $20,000. But Consumer Reports estimates the average EV battery pack’s lifespan to be at around 200,000 miles. That is also the life expectancy of the average car.

While electric vehicles price is becoming increasingly competitive, electrifying the transportation sector will require a significant buildout of vehicle charging – both roadside and at home. Even with a charging infrastructure buildout, there are inconveniences for drivers that want to make long trips. The average range of a gas-powered or gas-hybrid vehicle is over 400 miles; for electric vehicles it is about 250 miles. On a road trip, charging times for EVs vary between 20 minutes and 55 minutes, depending on the state of the car’s battery and the speed of the chargers used; that is significantly longer fueling a car with gas. These inconveniences could be counterproductive in that they could lead to more air travel.

Equity issues are even more difficult in the freight industry. Truck transportation is responsible for moving 70% of all freight within the U.S. There is a long tail to the trucking industry. For example, in long haul freight there are 36,000 firms, 32,000 of these firms employ less than 10 employees. These smaller firms are typically much less profitable than the giant carriers. A new semi-truck costs between $70,000 and $150,000, an electric semi is between $300,000 and $400,000. Many small freight firms simply will not be able to afford this without very large government subsidies.

The charging issues are even more significant for moving freight than for passenger travel. Currently, electric trucks are only viable for short and midrange vehicles. There is a potential play for autonomous electric semitrucks. Because autonomous trucks are not subject to hours-of-service laws, they can travel much further than single passenger trucks without stopping. With the right network, longer stops for charging would be more than balanced out by lower downtime hours for the drivers. However, a safe estimate is that we are ten years away from this kind of solution.

Global fossil fuel use has risen alongside economic growth since the start of the Industrial Revolution. Reducing carbon emissions while continuing to expand the global economy, and doing this in an equitable manner, will be the pivotal challenge of the coming century. If the transportation sector provides any guide, doing this at the pace that is needed will be an almost herculean task.