How the ICAO’s carbon offsetting scheme will mean cleaner skies

For the environmentally conscious, it can be tricky to fly on an airplane: the impact of aviation on the planet is heavy, especially when it comes to carbon emissions. Some critics say flying is the biggest carbon sin and one of the largest individual contributors to climate change. But the aviation sector is well aware of the problem, and it has been addressing it in various ways.

Last month, a United Nations negotiation finally sealed key rules on the landmark 2016 deal to curb airplane emissions. The International Civil Aviation Organization (ICAO), a UN agency, adopted the first ever international mechanism for its Carbon Offsetting and Reduction Scheme for International Aviation (CORSIA).

The plan obliges airlines to monitor and report their emissions from 2019 as the first step towards creating a strategy for reducing carbon dioxide emissions in aviation. It is part of a package of measures including technology, sustainable aviation fuel, operational and infrastructure advances which aim to continue to reduce the sector’s carbon emissions.

This market-based scheme measures aviation emissions from a baseline to be set in 2020: those that exceed this level will then have to be offset by all countries, with exceptions for developing nations, unless they choose to volunteer.

A controversial last-minute addition to the deal allows conventional fossil fuels to be recognized alongside sustainable aviation fuels under CORSIA if they can achieve a 10% reduction in lifecycle carbon dioxide emissions. This has drawn the anger of campaigning groups. Transport & Environment (T&E) describes the change as “the latest weakening” of the global offsetting scheme and is sceptical about how fossil fuels could ever be considered a green option. “Airlines burning kerosene could be rewarded with reduced obligations to buy carbon offsets simply because the refinery producing the oil was running on renewable electricity,” T&E said.

But the International Air Transport Association, which represents airlines, says the offset scheme is a “pragmatic compromise” that will deliver carbon neutral growth from 2020. It says the agreement will provide clarity in government and airline preparations for carbon offsetting.

Global aviation currently moves 10 million passengers around every day, pumping out enough emissions to contribute 1.3% to the overall total of greenhouse gases emitted from all sources. Aviation’s emissions share is expected to leap to 22% by 2050, placing growing pressure on the sector to help the world avoid further global warming.

Jet fuel emissions are just one aspect of how flying affects climate change – others include the manufacturing process and technology operations like infrastructure, from air traffic control to ground handling. New technologies have been introduced over the years to reduce emissions, like winglets, the wingtip devices intended to improve flight efficiency, and ever-more sophisticated avionics, as well as composite materials to reduce weight.

International deals are always compromises, and CORSIA is no exception. It has to take account of many different interests, and aims to lower emissions while limiting economic costs. Even if it is not perfect, the CORSIA deal lays the foundations for a shift towards greener aviation.