Airlines have long charged customers more for on-board food, extra baggage and superior legroom. Deutsche Lufthansa AG now wants customers to pay for reducing the environmental impact of flying.

Europe’s biggest airline will offer an option of so-called Green Fares to travelers from Wednesday, adding a surcharge to purchase sustainable aviation fuels and carbon offsets. The move marks the latest attempt by a European airline to soothe concerns over the environmental impact of flying, the most-carbon intensive form of travel. 

“People don’t just want to fly and discover the world - they also want to protect it at the same time,” Lufthansa executive board member for sustainability Christina Foerster said.

The new tickets will allow customers to offset their flight emissions with 20% so-called sustainable aviation fuels and 80% in contributions to climate protection projects, Lufthansa said. While the carrier didn’t say how much the new fares would cost but adding the offsets increased the price of a one-way economy fare from London to Frankfurt this week by around 7% to €230 ($245).

The surcharge paid by the passenger wouldn’t be used for buying fuel for the selected flight itself, but would be fed in to Lufthansa’s fueling purchase system. 

Airlines face a challenge charging travelers a bigger share of the potential $2 trillion cost to reach carbon neutrality by 2050. Lufthansa and other carriers already offer customers ways to pay extra for emissions, but that’s only a fraction of the spending. 

The German airline group has committed to halving its carbon emissions from 2019 levels by 2030. The plan includes buying newer, more efficient planes and making alternative fuel purchases. Its will also utilize offsets.