What is the CO2 emissions of a car?

CO2 emissions from cars are typically measured as grams of carbon dioxide released per kilometer driven (g/km) from the vehicle’s tailpipe, with broader “lifecycle” figures that include manufacturing and energy production. In everyday terms, a modern gasoline car often emits about 120–180 g/km, while electric vehicles emit zero from the tailpipe but may have lifecycle emissions that depend on how the electricity is generated.

Understanding the two main ways to measure car emissions

There are two primary ways researchers and regulators quantify a car’s impact: tailpipe (direct) CO2 emissions as it runs, and lifecycle emissions that account for how the car is built, fueled or charged, and eventually recycled. Both perspectives matter for policy, consumer choices, and climate goals.

Tailpipe CO2 emissions

The tailpipe measure captures only the CO2 released while the car is operating. It is the most visible metric for everyday driving and varies mainly with engine type, fuel, and efficiency.

Here are typical tailpipe CO2 ranges by drivetrain to illustrate how much cars differ in direct emissions:

• Gasoline-powered passenger cars: about 120–180 g CO2 per kilometer (g/km).


• Diesel-powered cars: about 110–160 g/km.


• Hybrid vehicles (gasoline-electric): roughly 40–90 g/km, depending on design and usage.


• Electric vehicles: 0 g/km from the tailpipe; lifecycle emissions depend on the electricity mix.

These ranges reflect a mix of compact to large vehicles and varying efficiency, with real-world results often influenced by driving style and conditions.

Lifecycle emissions and grid mix

Lifecycle emissions include manufacturing, fuel production or electricity generation, maintenance, and end-of-life handling. The relative advantage of electric vehicles often hinges on how clean the grid is where you charge them, as well as the battery manufacturing impact.

Key factors that shape lifecycle emissions include:

• Manufacturing impact: Battery production for electric vehicles adds upfront emissions, especially for larger packs.


• Electricity source: Grids that rely more on fossil fuels increase the emissions associated with charging EVs; cleaner grids reduce it.


• Vehicle lifetime: Higher mileage and efficient design spread a vehicle’s upfront emissions over more kilometers, lowering per-km impact.

Conclusion: In regions with cleaner electricity, electric vehicles typically show lower lifecycle CO2 emissions than conventional internal combustion engine vehicles over a typical life cycle; in dirtier grids, the gap narrows but often remains favorable for EVs over time as grids decarbonize.

What this means for consumers and policymakers

For consumers, understanding both tailpipe and lifecycle emissions helps in choosing vehicles that minimize climate impact over their entire use, not just on a single metric. Policymakers use these distinctions to set targets, incentives, and infrastructure needs that accelerate decarbonization.

Ways to reduce CO2 emissions from cars include:

• Opt for higher-efficiency vehicles (lower g/km) or electrified options (hybrid, plug-in hybrid, or electric).


• Charge EVs with electricity from low-carbon sources where possible.


• Maintain vehicles to preserve fuel efficiency and reduce emissions from wear and tear.


• Choose vehicles appropriate to your driving patterns to maximize efficiency gains.

Note: Official ratings can differ from real-world results due to driving behavior, terrain, climate control usage, and maintenance.

Summary

Car CO2 emissions are most commonly reported as tailpipe g/km, with electric vehicles offering zero tailpipe emissions but not zero lifecycle emissions. Modern gasoline and diesel cars typically emit around 100–180 g/km, while hybrids reduce that substantially. Lifecycle emissions depend heavily on how electricity is produced and the manufacturing impact of batteries. As grids decarbonize, EVs generally become a stronger option for reducing total emissions over a vehicle’s lifetime.

Does driving a car contribute to global warming?

Yes, cars contribute to climate change by emitting greenhouse gases like carbon dioxide, which trap heat in the atmosphere. The burning of gasoline and diesel fuels in internal combustion engines releases these gases, along with other pollutants that contribute to smog and acid rain. 
How cars contribute

• Greenhouse gas emissions: When cars burn fuel, they release carbon dioxide (CO2cap C cap O sub 2𝐶𝑂2), the most common human-caused greenhouse gas. A typical passenger vehicle can emit about 4.6 metric tons of CO2cap C cap O sub 2𝐶𝑂2 per year. 
• Other pollutants: Cars also emit other harmful pollutants, including: 
  • Nitrogen oxides (NOxcap N cap O sub x𝑁𝑂𝑥) and volatile organic compounds (VOCs), which react in sunlight to form ground-level ozone (smog). 
  • Carbon monoxide (CO), a poisonous gas from incomplete combustion. 
  • Particulate matter (PM), which consists of fine particles that can be inhaled, like soot. 
• Impacts of emissions: These emissions lead to various environmental problems: 
  • Global warming: Greenhouse gases from cars trap heat in the Earth's atmosphere, contributing to global warming. 
  • Acid rain: Nitrogen oxides can react with water vapor to form nitric acid, a component of acid rain. 
  • Smog and health issues: The combination of pollutants creates smog, which can cause respiratory problems like asthma. 

How to reduce contributions

• Drive less: Walk, bike, or use public transportation when possible, which are much lower-carbon options than driving, especially alone. 
• Carpooling: Share rides with others to reduce the number of cars on the road. 
• Trip chaining: Plan errands to be done in one trip instead of multiple separate trips. 
• Maintain your vehicle: Keep your car in good working order. Removing unnecessary items like roof racks can also improve aerodynamic efficiency, reducing fuel consumption. 

How much CO2 emissions from a car?

A typical gasoline car emits about 4.6 metric tons of CO2cap C cap O sub 2𝐶𝑂2 per year, which averages to about 411 grams of CO2cap C cap O sub 2𝐶𝑂2 per mile. This figure can vary significantly based on the vehicle's fuel economy, the type of fuel, and driving habits. 
Annual and per-mile emissions

• Annual: A typical passenger vehicle emits approximately 4.6 metric tons of CO2cap C cap O sub 2𝐶𝑂2 per year, assuming an average fuel economy of 22 miles per gallon and 11,500 miles driven annually. 
• Per mile: One gallon of gasoline produces about 8,887 grams of CO2cap C cap O sub 2𝐶𝑂2. This works out to an average of 411 grams of CO2cap C cap O sub 2𝐶𝑂2 per mile for a typical car. 

Factors that influence emissions

• Fuel economy: Vehicles with better fuel efficiency produce less CO2cap C cap O sub 2𝐶𝑂2 per mile. 
• Driving style: Stop-and-go traffic can increase emissions compared to steady highway driving. 
• Type of vehicle:
  • Gasoline cars: Every gallon of gasoline burned produces about 8,887 grams of CO2cap C cap O sub 2𝐶𝑂2. 
  • Hybrid cars: Generally have lower emissions than conventional gasoline cars. 
  • Electric vehicles (EVs): Produce zero tailpipe emissions. However, CO2cap C cap O sub 2𝐶𝑂2 can be emitted during the generation of the electricity used to charge them, so their overall footprint depends on the local power grid's mix of energy sources. 

What is a normal CO2 emissions for a car?

The average passenger car in the U.S. emits about 400 grams of CO2cap C cap O sub 2𝐶𝑂2 per mile, which totals approximately 4.6 metric tons of CO2cap C cap O sub 2𝐶𝑂2 per year. New cars in Europe have lower average emissions, with 108.2 g CO2cap C cap O sub 2𝐶𝑂2/km in 2022, due to the increasing share of electric vehicle registrations. 
Average U.S. emissions

• Per mile: About 400 grams of CO2cap C cap O sub 2𝐶𝑂2 per mile.
• Per year: Approximately 4.6 metric tons of CO2cap C cap O sub 2𝐶𝑂2 per year, based on an average of 11,500 miles driven and a fuel economy of about 22.2 miles per gallon. 

Average European emissions (new cars)

• 2022: 108.2 grams of CO2cap C cap O sub 2𝐶𝑂2/km. 
• 2023: 106.8 g CO2cap C cap O sub 2𝐶𝑂2/km. 
• Impact of EVs: The growing number of electric vehicles is a key factor in lowering the average emissions for new cars in Europe. 

Are cars the biggest polluters?

No, cars are not the biggest polluters overall, as the fuel and energy sector (including power plants) is the largest source of pollution globally, but they are a major contributor to pollution, especially in the transportation sector and in urban areas. Cars and trucks are a significant source of greenhouse gases and air pollution, and in the United States, transportation is the largest source of greenhouse gas emissions, with cars and trucks accounting for about one-fifth of the total.
 
Cars as major polluters

• Cars and other light-duty vehicles are the largest part of the transportation sector, which is a major source of greenhouse gas emissions. 
• In the U.S., transportation accounts for the largest portion of total greenhouse gas emissions, and cars and trucks are the biggest polluters in this sector. 
• Cars emit other air pollutants, including nitrogen oxides and particulate matter, which can have immediate impacts on human health, especially in urban areas where emissions are released at street level. 

Global vs. sector-specific pollution

• Globally, the fuel and energy sector, which includes power generation from fossil fuels like coal, oil, and gas, is the largest contributor to climate change. 
• Transportation as a whole (which includes cars, trucks, planes, ships, and trains) is one of the largest contributors to climate change, but it is a part of the larger fuel and energy problem. 
• The transportation sector is also a major source of air pollution, contributing to the formation of ground-level ozone, particularly in cities.