Transportation is responsible for nearly a third of all greenhouse gas emissions. This means that if you want to reduce your individual carbon footprint, the way you travel might be one of the best places to start. A new app called Aerial tries to help you offset those emissions by looking into your mailbox.

Be it your Uber invoices, flight reservations, or train tickets, chances are that you can find most of your travel history in your email. That’s exactly what Aerial looks at to calculate the carbon emissions of each of those journeys, after which it tells you how to offset them.

The new app, which launched less than a week ago, is the brainchild of three tech entrepreneurs with combined working experience at Microsoft, Google, and Facebook, who wanted to allow everyday travelers to reduce their travel-related environmental impact.

“A nice analogy is: the same way Instagram turned everyone into a photographer,” says Ebby Amir, one of the co-founders, “we want Aerial to turn everyone into taking climate action.”

The app works by scanning the user’s connected email account for their plane, train, and ride-hail trips, and presents them with an estimate, in kilograms, of carbon emissions for each trip taken.

Aerial will also show the user an estimate of how much they should contribute to offset the carbon emissions of each individual ride, at a rate of $10 per ton. “So, you’re essentially purchasing a carbon-offsetting credit,” says Andreas Homer, one of the other cofounders.

Currently, users can get their carbon-offsetting credits by donating to a forest conservation project, and help conserve a given number of trees in McCloud, a forest near Mount Shasta in Northern California.