Can the UN make air travel more sustainable?

An industry often overlooked in climate efforts is looking to clean up its act.

In a meeting in Montreal on Monday, the International Civil Aviation Organization (ICAO), an arm of the United Nations, agreed on international standards to limit carbon emissions from aviation in an ongoing effort to limit gases that trap heat in Earth’s atmosphere. Twenty-three countries participated in crafting the agreement, including many that manufacture aircrafts and engines.

Airplane emissions have proved difficult to control because of the international nature of the industry and limited alternatives to carbon-based jet fuel. Even last year’s Paris climate agreement left air transport and maritime shipping outside its reach.  

Aviation currently contributes around 11 percent of the transportation sector’s global emissions, according to the White House, or around 2.5 percent of all emissions globally. That’s just shy of Germany’s output of heat-trapping gases. Because they are released in the upper atmosphere, emissions from aviation actually warm the atmosphere faster than most other carbon emissions.

The new ICAO standards will require  the world’s largest airliners to upgrade their fleet to more fuel-efficient planes.  Manufacturers will have to discontinue the production of aircrafts with a heavy carbon footprint by as early as 2023. All new aircrafts will be required to meet the new ICAO standards by 2028 and reduce their fuel consumption by an average of 4 percent compared to 2015 levels.

The guidelines are part of a two-part strategy that experts say will eventually lead to an international carbon price for aviation emissions. While the new guidelines alone aren’t enough to reduce aviation emissions substantially, experts say they are an important step forward as the world grapples with the environmental impact of our airborne economy.

“None of the policies we’re debating in 2016 are able to bring down emissions. They are meant to form the foundation for more aggressive action later,” says Dan Rutherford, aviation director at the International Council for Clean Transportation (ICCT), a research-based non-profit.

“But it’s the first chance for the aviation industry to say it’s in the game, too, and it’s going to contribute to meeting climate protection goals.”

Experts largely agreed that an international standard should be put in place to limit emissions from aviation, but consensus over regulations has been difficult to come by. The ICAO negotiations that led to Monday’s announcement were ongoing for six years.

Already, there are signs that some of the world’s largest emitters are looking to scale back aviation’s climate impact. In January, the European Union released its first European Aviation Environmental Report, aiming to better monitor the environmental impact of Europe’s airlines and determine whether the policies in place are effective.

All flights within the European Economic Area, which includes the 28 EU member states, Iceland, Liechtenstein, and Norway, have been included in the EU emissions trading scheme since 2012. But this year the European Commission is expected to propose measures to include international flights in the equation, and their recommendations will likely be based off of ICAO’s standards.  

On the other side of the Atlantic, the Obama administration is also pushing for aviation emissions to be regulated. In June last year the Environmental Protection Agency (EPA) announced it would begin developing requirements for US airlines, which experts say contribute roughly a third of aviation emissions worldwide.  China has also said it would include airlines in the cap-and-trade system it plans to launch in 2017.

As governments think about effective policies, scientists are looking for new ways to make flying more sustainable. Zero-carbon flights are still a long way off, some important inroads are being made.

Oslo recently became the world’s first airport to provide all airlines refueling there with sustainable jet biofuel. The fuel is made from Spanish camelina, a flax-like plant that grows in abundance in the Mediterranean. In the United States, EasyJet announced it would begin testing whether hydrogen fuel cells can power its jets.

New aircraft models, like the Boeing 787 Dreamliner and the Airbus A320neo, are also being made with pending standards in mind.

Boeing welcomed ICAO’s announcement on Monday and confirmed it’s “fully committed” to meeting the new standards.

"This agreement represents real progress beyond the substantial industry achievements already made to reduce aviation emissions, with more steps ahead,” reads a company statement.  

But even if the standards change the way aircrafts are made, some say that they don’t go far enough to reduce emissions.

"The proposal will only require CO2 reductions from new aircraft of 4 percent over 12 years, when market forces alone are predicted to achieve more than a 10 percent efficiency gain in the same time frame,” Drew Kodjak, executive director of the ICCT, said in a statement. “This is an anti-backsliding standard.”