You would never leave for a trip without knowing how you would get to your destination. And yet, the global airline industry just did exactly that.
Last week, 190 countries agreed to slash carbon pollution from international flights. While world leaders celebrated the deal, the path to low-carbon air travel remains largely uncharted. If airlines are to meet the goals of the agreement, they will need to streamline operations, engineer more efficient planes and develop cleaner-burning fuels.
Here’s a look at the breakthrough agreement that will propel innovation in air travel, and the tools airlines might use to rein in planet-warming emissions.
Planes pollute a lot. This agreement will help keep pollution in check.
Air travel accounts for a narrow slice of global carbon pollution — just 2 percent — but it’s growing every day. Demand for air travel is projected to double over the next two decades, threatening to drive up emissions from commercial flights even more.
Despite its sizable role in climate change, international air travel was left out of the Paris Climate Agreement. Why? Simply put, accounting for pollution from aircraft is difficult. Do emissions belong on the balance sheet of the country of departure or the country of arrival? What about the nationality of the passengers? How about the airlines?
Rather than litigate these questions in Paris, countries left the issue to the International Civil Aviation Organization (ICAO), the UN agency that governs international air travel. Following years of deliberation, members of ICAO agreed to cap emissions at 2020 levels. The mandate means that even as more and more planes take to the skies, collectively, airlines will never pollute more than they did in 2020.
At least that’s the idea. It remains somewhat unclear how airlines will meet this goal. There are four possible routes to cut pollution from air travel. We’ll take a look at each.
1. Carbon offsets
One way to cut carbon pollution is to pay someone else to stop polluting on your behalf. For airlines, this is an appealing route. Today, there are no practical, zero-carbon alternatives to conventional airplanes that can be produced at scale—no Tesla Model 3 of the skies. But for a small cost, airlines can cut carbon pollution on the ground to offset the emissions generated by a commercial flight. This is called a carbon offset.
Suppose you’re flying from the United States to Jamaica. Your hotel in Kingstown runs on natural gas, and the hotel manager wants to install a set of solar panels. Part of the cost of your plane ticket would go to funding that project. Thanks to its new solar panels, the hotel pollutes less, offsetting emissions from your flight.
The tricky part is the accounting. Could the hotel have afforded solar panels without the help of the airline? Would they have installed the panels anyway?
“What qualifies as an offset is reducing emissions below what would have happened in the absence of the project,” Annie Petsonk, International Counsel at the Environmental Defense Fund, said in an interview. “And that can be difficult to prove.” If well-accounted for, offsets can offer a meaningful way to cut pollution.
2. More efficient planes
If you looked out the window on your last flight, you may have noticed the shark fin-shaped protrusions on the ends of the wings. These are called “winglets” or, if you’re cool, “sharklets.” They cut drag, helping airplanes save fuel.
Winglets are just one way to make planes more efficient. Airlines will need to find other ways to cut fuel consumption. That could mean lighter materials, more efficient engines or super-thin wings held up by trusses. As airlines develop better planes, those technologies could help us cut pollution in other areas.
“The aviation industry is kind of a cornucopia of technological innovation that spreads to other industries,” said Petsonk. She explained that a high-efficiency gas-fired power plant, for example, is a variation on a jet engine.
3. Faster routes
Most flights don’t follow a direct path. Typically, planes are routed over radio stations on the ground. Think of it like an airborne version of connect the dots. This system made sense 50 years ago when navigation systems were more primitive, but today airplanes could use satellite technology to navigate instead.
This transition is already in the works. As airlines and air traffic controllers implement the technology, planes will be able to fly more direct routes, cutting down on fuel consumption and carbon pollution.
We’re a long way off from seeing all-electric commercial aircraft. But, in the not-too-distant future, we can look forward to planes that run on biofuels. These are fuels made from corn, sugarcane or algae. Let’s focus on algae.
Algae photosynthesize. They take in carbon dioxide, water and sunlight, and they produce fatty oils that can be turned into jet fuel. When burned, algae-based fuels produce carbon dioxide. They are effectively carbon neutral, meaning they don’t add any additional carbon dioxide to the atmosphere.
Biofuels aren’t perfect. Algae growers may generate carbon pollution in powering their operations, drawing electricity from coal-fired power plants or driving gas-powered cars and trucks. As operations become cleaner, so will the resultant fuels.
Biofuels have real promise for air travel. Expect to read more about them in the next few years. Boeing, in collaboration with several Japanese airlines, will offer algae-fueled flights to the 2020 Olympic Games in Tokyo.
The future of international air travel
Historically, Petsonk explained, a spike in the price of fuel drove innovation among manufacturers and airline operators. When prices dropped, airlines saw less reason to invest in efficiency. Investment in innovation waxed and waned with the price of jet fuel.
The ICAO agreement sends a clear signal to airlines that will drive research into efficient planes and low-carbon fuels. Countries with major commercial airlines have signed on, including China, Singapore, the European Union and the United States. As manufactures and airline operators make gains, we will see emissions start to level off.
Will this drive up the cost of plane ticket? The International Air Transport Association estimates the agreement will add around $5 to $7 to the price of an airplane ticket in 2030. That’s a nominal figure — about a third of the cost of checking a bag on most airlines. It’s a small price to pay for a potentially huge reduction in global carbon pollution.
To the people who are already grappling with drought, extreme heat and supercharged storms fueled by climate change, it represents huge gains. Petsonk recalled a scene from ICAO negotiations.
“There were countries who were in the direct line to be hit by Hurricane Matthew, who were pleading with their colleagues in the assembly: ‘Approve this resolution… This is our survival. This is our future.’ Aviation needs to do its part in terms of reducing the emissions that are contributing to climate disruption.”