The airline industry is taking its carbon emissions seriously. Aviation accounted for 2.4% of total worldwide carbon dioxide emissions in 2018. That may not sound like a lot, but as the European Commission's Directorate-General for Climate Action points out, "If global aviation was a country, it would rank in the top 10 emitters."

Aviation CO2 emissions, including both passenger and cargo flights, have increased by 32% over the past five years, according to a report last month from the International Council on Clean Transportation, an independent nonprofit organization.

Greta Thunberg, the 16-year-old Swedish environmental activist, has shone a spotlight on the issue by pointedly giving up air travel in order to reduce her carbon footprint. In August, she traveled across the Atlantic by sailboat to speak at the UN Climate Action Summit in New York.

Sweden has become a center of a movement to forgo air travel. The Swedes have even coined the word flygskam, meaning "flight shame."

Against this background, the airline industry's trade association has scheduled an event for later this month devoted partly to finding improved technological solutions for offsetting the carbon impact of aviation. The IATA AIR Hackathon (IATA is the International Air Transport Association, and AIR stands for airline industry retailing) is scheduled for October 11-13 in Frankfurt, Germany. Cloverly has been invited to be the featured API for carbon offsetting.

"There is no alternative to aviation when it comes to long distance and low carbon travel," says IATA on the hackathon's web page. "Carbon offsetting can therefore be seen as an immediate, direct, and pragmatic means to encourage action to limit climate change impacts, at least in the short term."

IATA says more than 30 member airlines (of its 291 airline members worldwide) have introduced offset programs. That number will have to increase dramatically for the airline industry to reach its self-imposed target of making all growth in international flights after 2020 carbon neutral.

Carbon offsetting represents a huge part of the industry's plan for achieving that goal. The plan is called the Carbon Offsetting and Reduction Scheme for International Aviation, or CORSIA. IATA says CORSIA would require aviation to offset an estimated 2.9 billion tons (2.6 billion metric tons) of CO2 from 2021 through 2035.

The International Civil Aviation Organization developed CORSIA. ICAO is a UN agency that sets global rules and standards for air travel.

The United States is an ICAO member. The Federal Aviation Administration says aircraft operators representing more than 97% of total international emissions by US operators have voluntarily signed on to the CORSIA program. They include all major US airlines, most smaller carriers, major shipping companies, and such corporations as International Paper, Tyson Foods, First Data, and Dole Foods.

The CORSIA program calls for airlines to achieve carbon-neutral growth starting in 2020. Planned decarbonization measures include better air traffic management, improvements in aircraft technology, use of sustainable alternative fuels, and such "market-based measures" as carbon offsetting.

ICAO anticipates that capping net aviation CO2 emissions starting in 2020 will require better air traffic management and improvements in aircraft technology. The biggest component of its plan, however, is increased use of "market-based measures" (mostly meaning CORSIA) and "sustainable alternative fuels."

Michael Gill, IATA's director for aviation environment, speaks about sustainability in a video on the IATA website. In it, Gill says IATA has called on all governments to participate in CORSIA.

As for how airlines will comply, he said he sees "a lot of work on new aircraft technology, a lot of work on electrification, and we see some [technological] solutions potentially coming online in the 2035 time frame. But where I really see the most exciting developments is in the area of sustainable aviation fuel. We've now had nearly 200,000 commercial flights using a blend of sustainable aviation fuel."

Sustainable aviation fuel is made by blending conventional jet fuel (kerosene) with renewable hydrocarbons. The renewables can come from a variety of sources, including biomass (for example, algae, salt marsh grasses, or crops that are grown specifically as fuel, such as camelina and jatropha); cellulose waste from the wood, agriculture, and forestry industries; used cooking oil; and even municipal solid waste that would otherwise go to landfills.

Proponents of sustainable aviation fuel claim that, depending on the source of the renewable hydrocarbons, using the fuel can result in up to an 80% reduction of carbon dioxide emissions across the fuel's life cycle.

Annual airline passenger numbers are projected to double to 8.2 billion by 2037. IATA has pledged that the aviation industry will achieve a net reduction in carbon emissions of 50% by 2050, relative to its 2005 emissions.

"We want to call on the industry to go for even more ambition in the coming years on that," Gill said. "But it's an area where we are looking into it, we have a plan in place, and I believe that should reassure the flying public that aviation is a very responsible industry as far as climate change is concerned."