Every time we step into a car or board a plane, we make a choice that ripples far beyond our own lives. Transportation is one of the largest contributors to climate change, yet it’s often overlooked. How—and how often—we move from place to place may be one of the most tangible ways individuals can reduce their carbon footprint.

Carbon dioxide (CO2), the primary greenhouse gas fueling global warming, is released whenever fossil fuels are burned—whether gasoline in a car or jet fuel in an airplane. But not all travel is created equal. Airplanes, vans, and personal vehicles are the heaviest polluters per passenger, while walking, biking, trains, and electric cars powered by renewable energy offer dramatically lower emissions.

The consequences of climate change are no longer distant forecasts. Rising global temperatures intensify wildfires that consume forests in days, trigger floods that wash away homes and roads, and worsen droughts that starve crops. Hurricanes surge farther inland, coral reefs bleach, oceans acidify, and entire communities face economic upheaval. Many people assume that their individual choices are insignificant, or that climate change is too abstract to connect with daily life. In truth, every decision—each mile driven, each flight taken—adds up.

Air travel is one of the most carbon-intensive ways to travel. Keeping a 130,000-pound plane suspended 35,000 feet above the Earth requires enormous quantities of jet fuel. A single round-trip flight from New York to California produces roughly one metric ton of CO2 per passenger. Fly to Asia, and it can reach five metric tons—roughly equal to what a person in much of the developing world emits in an entire year. A single international trip can double an individual’s annual carbon footprint. Americans make up only 4% of the world’s population but account for roughly half of all CO2 emissions from air travel, while 85% of the global population has never flown.

Cars are no less consequential. The average passenger vehicle in the U.S. emits about 4.6 metric tons of CO2 annually. Each gallon of gasoline burned releases around 8,900 grams of CO2. Multiply that across hundreds of millions of cars, and the numbers are staggering. Cars also require roads, bridges, and tunnels, whose construction and maintenance come with their own environmental costs.

Comparing cars and planes is not straightforward. Emissions vary depending on passengers, distance, and route efficiency. Jet contrails, which trap heat high in the atmosphere, add another layer of complexity. Both forms of travel have hidden environmental costs, making trains, buses, and bicycles far more sustainable. Trains, for example, emit roughly 90% less CO2 per passenger than equivalent car or plane journeys.

Policy and regulation shape these choices at a larger scale. Fuel economy standards, emissions regulations, and investments in clean technology have historically nudged transportation toward lower-carbon alternatives. Market forces push innovation, too: airlines save money by burning less fuel, and carmakers are investing heavily in electric vehicles, with many planning to phase out gasoline-powered cars within decades. Yet enforcement of environmental rules has not always kept pace with scientific urgency.

Still, individual choices matter—and they matter enormously. Walk, bike, or take public transit whenever possible. Carpool when you can, and choose nonstop flights if flying is unavoidable, since takeoffs and landings consume the most fuel. Support clean transit policies, from bike-sharing programs to rail expansions and electric vehicle infrastructure. Tools like carbon footprint calculators make it possible to see how lifestyle changes can meaningfully reduce emissions.

Transportation is often framed as an overwhelming contributor to climate change, but it is also a place where every decision can produce real, measurable results. Each mile matters. Each choice counts. By moving differently, we can cut emissions, reduce reliance on fossil fuels, and help build momentum for the systemic change our planet urgently needs. The road to a sustainable future begins with the choices we make every day.