"Flights associated with the main Portuguese airports, considered only in one direction (and not round trip), resulted in 4.75 million tonnes of greenhouse gas emissions in 2018," stated Zero, based on data Airport Tracker, a tool launched by the European Federation of Transport and Environment, of which the environmentalist association Zero is a member.

Lisbon airport is, according to the same source, the main airport responsible for emissions associated with departure flights, with 3.03 million tonnes of greenhouse gases (64 percent of total emissions), followed by Porto, with 0.977 million, and Faro (0.57).

“In the future, battery-powered aircraft may be suitable for shorter flights and hydrogen powered aircraft are more promising for long-haul travel. However, since even major manufacturers believe that traditional jet engines will dominate by 2050, these technologies are unlikely to arrive in time to limit the industry's climate impact to meet global decarbonisation targets,” warns ZERO.

“For Zero, it is essential to consider the total emissions associated with the total flights in the climate neutrality objectives and not only include domestic flights and emissions associated with landings and take-offs”, concludes the statement.