To help you make more sustainable travel choices, you can find carbon emission estimates on your flight search results and booking pages.
Find carbon emission estimates
- Go to Google Flights.
- Search for a flight.
- On the right-hand side, click the down arrow.
- You'll find the emission estimates for each part of your trip.
Sort by carbon emissions
- On the right-hand side, click Sort by CO2 emissions.
- Your flight search results will be ordered from lower to higher emissions.
Filter by low emissions
- At the top, click the Emissions filter Low emissions only.
- Your flight search results will only show options with lower than typical emissions for that route.
How we estimate carbon emissions
Google uses the European Environmental Agency (EEA) emission estimates with the most up-to-date algorithmic model from 2019. Learn about the model with the EEA guidebook.
The non-CO2 effects of flying
Climate effects caused by flying include CO2 emissions and non-CO2 effects, including the warming caused by the formation of persistent contrails. Contrails are trails of condensation that trap heat in the atmosphere. Persistent contrails can account for a significant portion of a flight's climate impact.
Google is working with scientists, academics and industry experts to make reliable predictions about contrail impact per flight. Eventually, we plan to include these predictions in the model used to estimate emissions.
Why some flights have lower emissions
Carbon emission estimates consider the origin, destination, aircraft type and the number of seats in each seating class.
Factors such as fuel-efficient aircraft and shorter routes usually result in lower carbon emissions.
The emission estimates are higher for premium economy, business and first seating classes because the seats in these sections take up more space. They'll account for a larger share of the flight's total emissions.
Travelling by train
When a train is available on your route, you will find it listed in your Google Flights search results.
Travelling by train may result in significantly lower carbon emissions compared to flying. Carbon emissions for trains are compared to the typical flight for that route. As such, train options are mostly marked with a badge indicating lower emissions.