How Much CO2 Does a Flight Emit? (And How to Offset It)

A single passenger's flight typically emits about 0.2–0.5 tonnes of CO₂ on a short-haul return and roughly 1–2 tonnes on a long-haul return like London–New York in economy. Those are useful ballpark figures, but the real number depends on distance, cabin class, how full the plane is, and a high-altitude warming effect that most calculators leave out.

Real per-passenger figures

• Short-haul return (say London–Rome or a domestic hop) lands around 0.2–0.5 t CO₂ per economy seat.
• Medium-haul return (London–Cairo, roughly 4,000 km each way) sits near 0.7–1 t.
• Long-haul return like London–New York is about 1–2 t per economy passenger; London–Singapore or Sydney can reach 3–4 t.
• Cabin class multiplies it — business seats take 2–3x the space and emissions of economy, and first class 3–4x, because the footprint is shared across fewer people.
• Load factor matters — a half-empty plane spreads its fuel burn across fewer passengers, pushing per-head emissions up.

The high-altitude effect most calculators miss

Burning jet fuel does not only release CO₂. At cruising altitude, aircraft also produce contrails, water vapour and nitrogen oxides that trap extra heat — a phenomenon called radiative forcing. Peer-reviewed estimates suggest this roughly doubles a flight's total warming impact compared with the CO₂ figure alone. So a long-haul return that shows as 1.5 t of CO₂ may be closer to 3 t in real climate terms. When you work out your own flights with the free Evertreen CO₂ calculator, treat the CO₂-only output as a floor, not a ceiling.

How to cut it — then offset the rest

The biggest lever is simply flying less: one avoided long-haul trip saves more than a year of most other lifestyle tweaks combined. When you do fly, choose direct routes (take-off and landing burn the most fuel), pick economy over business, pack lighter, and favour newer aircraft where you can. For the emissions you cannot avoid, offsetting with real, verifiable projects closes the gap. Evertreen's geolocated trees come with a GPS pin and progress photos so you can see exactly what your money planted, and you can start from just £1.5 per tree.

Choosing a credible offset

Offsetting only works if the carbon is genuinely additional and independently checked, which is why quality standards matter. Evertreen offers certified Verra and Gold Standard carbon credits on request for the residual tonnes a flight leaves behind — the same registries used by serious corporate buyers. Pairing traceable trees for a visible, long-term impact with certified credits for measured, retirable tonnes gives you an honest response to air travel: reduce first, then offset what is left with something you can actually verify.

Frequently asked questions

How much CO₂ does a return flight from London to New York emit? Roughly 1–2 tonnes of CO₂ per economy passenger, or closer to 3 tonnes once the high-altitude warming effect is included. Business or first class can multiply that by 2–4 times.

Does economy really emit less than business class? Yes — a business seat occupies 2–3 times the floor space of economy and first class up to 4 times, so the same flight's fuel is shared across fewer people, raising the per-passenger footprint proportionally.

How many trees offset one long-haul flight? As a rough guide, a mature tree absorbs around 20–25 kg of CO₂ per year, so offsetting 2 tonnes takes a modest grove planted over time; certified credits retire the tonnes immediately if you need proof for a given year.