The world’s biggest search engine has taken a key driver of global warming out of the carbon calculator embedded in the company’s Google Flights search tool, making journeys appear to have much less impact on the environment than before. Dr. Doug Parr, chief scientist of Greenpeace, says, “Google has airbrushed a huge chunk of the aviation industry’s climate impacts from its pages.”

With Google hosting nine out of every 10 online searches, this could have wide repercussions for people’s travel decisions. In July, the search engine decided to exclude all the global warming impacts of flying except CO2 following consultations with its industry partners.

Kit Brennan, a founder of Thrust Carbon, a UK company that helps businesses reduce the effect their travel has on the climate, fears consumers could come to believe that non-CO2 impacts on the climate are not relevant in the longer term, despite the science that contradicts this view. That would mean up to 1.5 percent of the warming caused by human activity would be ignored, and the pressure on airlines to reduce their emissions would be cut accordingly. Some experts say Google’s calculations now represent just over half of the real impact of flights on the climate.