According to climate experts, Google has "airbrushed" the full environmental impact of air travel through updates made to its flight carbon calculator in July.
Critics say the calculator - which estimates the potential impact of different flights on the climate - effectively halved total emission figures when it began excluding "carbon dioxide equivalent" emissions involved in flying, such as water vapour, last month.
Contrails - the wisps of ice crystals left in the air in the wake of a plane - reportedly contribute to global warming as they trap heat radiated from the Earth in the atmosphere.
Professor David Lee of Manchester Metropolitan University says the change means the calculator "now significantly understates the global impact of aviation on the climate." While aviation reportedly accounts for around 2% of global CO2 emissions, it's responsible for around 3.5% of human-caused global warming.
Google has stated that offering an accurate estimate of CO2 equivalent emissions is impossible. In a statement, they said, "we strongly believe that non-CO2 effects should be included in the model, but not at the expense of accuracy."
Many have responded to the news with concern, as the reach of the calculator spreads beyond Google to use by travel sites such as Skyscanner and Expedia.
Narrative A, as provided by Euro News. Google is greenwashing the effects of the aviation industry and hundreds of millions of users are underestimating the environmental impact of their journeys as a result. Carbon footprint calculations are crucial to understanding the cost of human activity - Google needs to be held accountable for misleading consumers.
Narrative B, as provided by The Guardian. While Google's poor practices are certainly irresponsible, the very notion of a "carbon footprint" was the brainchild of big oil, designed to shift accountability for climate change from corporations onto individuals. Rather than concentrating on private individual actions to tackle global warming - as is encouraged by programs like carbon calculators - we must seek collective action and policy reform.