What percentage of carbon emissions is caused by transportation? How can we reduce transportation CO2 emissions?
Transportation accounts for 16% of carbon emissions worldwide. The main culprits are personal vehicles, especially in the U.S., where public transportation is not well developed.
Let’s look at the main barriers and potential solutions to curbing transport-related emissions.
Curbing Transportation Emissions
Transportation is the biggest source of emissions in the U.S., with roughly half of those emissions coming from personal vehicles. Without a large-scale shift to electric cars and carbon-less electricity to charge those cars, we can expect emissions from personal vehicles to increase as car ownership becomes more common globally.
The two most significant barriers to reducing personal transportation CO2 emissions with electric cars are the availability of carbon-less electricity (if we use fossil fuels to generate the electricity used to charge the car then we’re just swapping one fossil fuel for another) and the purchase cost of an electric vehicle. However, Gates estimates that the price of an electric car will be similar to the price of a gas-powered car by 2030, and sooner should gas prices increase.
|Electric Cars Aren’t Carbon-Free|
While electric cars are generally more climate-friendly than gas-powered ones, building them is a materials- and energy-intensive process that still produces carbon emissions and impacts the environment. For instance, producing the batteries in electric cars actually takes more materials and water and releases more carbon dioxide than producing traditional combustion engines. Furthermore, battery materials like cobalt, rare earth metals, and lithium are linked to environmental pollution and human rights concerns.
Another environmental hurdle for electric vehicles is the electricity needed to charge them. Charging electric vehicles with electricity from coal-fired power plants can actually emit more carbon dioxide than fueling an efficient gas-powered car. In contrast, charging an electric car with solar power virtually eliminates running emissions. Therefore, how well an electric vehicle outperforms a traditional model’s emissions will depend on how it’s charged. (The US Department of Energy Alternative Fuels Data Center offers a calculator that compares emissions from different types of vehicles by state based on electricity sources.)
Nearly a third of the remaining global transportation emissions come from large trucks and buses, as well as another 10% from cargo and cruise ships and 10% from airplanes. Unfortunately, these larger vehicles are more difficult to electrify because current battery technology is 35 times heavier than gas and would require vehicles to make frequent recharging stops. The resulting loss of efficiency makes current battery technology impractical for large vehicles. Gates notes that nuclear-powered ships are a carbon-free option and cites advances in alternative fuels as a promising solution for trucks and planes.
(Shortform note: A 2022 report by the Environmental Defense Fund takes a more optimistic view on the future of large electric vehicles. The study found that it will be cheaper to buy and maintain electric freight trucks and buses than those powered by combustion engines by 2027, largely because of advances in battery technology coupled with more affordable prices. Large companies are already switching to electric trucks: Amazon recently purchased 100,000 electric trucks, UPS is purchasing 10,000 electric delivery vehicles, and FedEx aims to be fully battery-powered by 2040. In contrast, the USPS sparked outrage in 2022 when it announced that it would continue to purchase thousands of gas-powered delivery trucks.)