If the aviation industry was a country, it’d rank among the world’s top 10 emitters of carbon dioxide (CO₂). Aviation emissions have risen by 70% since 2005 and as demand increases in wealthy and poorer countries, they’re forecast to increase by between 300% and 700% by 2050.
Arresting this incline is going to be the first step towards a sustainable system of international travel—but how could it be done? A frequent flyer tax would be relatively simple to implement however it could mean the richest can still afford to fly while the poorest are priced out.
Most plane passengers are already relatively wealthy. only eighteen of the world’s population have ever flown and in any given year, an elite 3-dimensional of the world flies. That’s about 230 million people, but flights carried four billion passengers in 2017. so the average flyer takes eight return flights and airplanes rack up seven trillion air miles each year.
Rationing might be a fairer and more effective alternative.
Every person could be allocated a max number of “flight kilometers” annually. This allowance would increase the longer a person abstained from flying. the first year allocation would be 500km, then the following year it’d be 1,000km and would double every year. it’d take seven years to accumulate enough to fly from the UK to Australia and back.
Buying a ticket for a flight of any distance would reset the allocation rate to year one, but the kilometers saved in a “flight bank” could still be used. Anyone, not traveling could exchange their flight kilometers for money, but anyone exceeding their ration could be penalized or prohibited from flying for some time.
Expanded and improved high-speed rail lines could also replace many flights. These journeys can be as fast as airplanes in some instances and emit 90th less CO₂. Solar-powered train journeys are already a reality in Australia. The Byron Bay Company uses solar panels on trains and platforms to power onboard batteries and exported 60,000kWh to the grid last year.
Coupling low-carbon train travel with flight rationing would limit emissions in the short term, however people are accustomed to traveling half the world in a matter of hours, typically at relatively low value. The demand won’t go away, therefore what could replace carbon-intensive air travel?
Most electric plane designs are grounded on the drawing board, however, there are some flight-ready aircraft. The world’s first all-electric commercial airliner was unveiled in Paris in June 2019. The craft is called Alice and it carries 9 passengers for up to 650 miles (1,040km) at 10,000ft (3,000 meters) at 276mph (440km/h) on a single charged battery. It’s expected to enter service in 2022.
The fossil fuel costs of small aircraft are regarding $400 per 100 miles. For Alice, the costs are projected to be as little as $8 for the same distance, and if the electricity is from renewable energy—perhaps generated by solar panels at the airport—then the plane could be zero-carbon.
How much energy each battery can store is increasing rapidly. but there are also strategies which can make electric planes more efficient. Capacitors are lightweight batteries that can hold a large charge but only for short periods. they could be used for takeoff—the largest energy requirement of a flight—than more traditional batteries could power the majority of the flight.
Innovation could deliver mass electric flight in the next few decades, however, an alternative to fossil-fueled flight will exists in the near future.
Bring back the zeppelin?
For as long as humans have taken to the skies we’ve had a low carbon alternative to burning vast amounts of fossil fuels to keep us up there—balloons. The Hindenburg disaster may have condemned the industry to relative obscurity for almost a century, but it has never really gone away.
The balloons of most modern airships are filled with helium instead of the explosive hydrogen used in the Hindenburg. concentrated helium is lighter than air and once divided into gas sacks, the vessel can stay aloft if any are breached while propellers powered by flexible solar panels can facilitate navigation.
Extracting enough helium fuel will be energy-intensive and there’s a looming global shortage. Luckily, advances made since the Hindenburg currently permit airships to fly on cylinders packed with hydrogen jet fuel, which is cheaper, lighter, and relatively abundant.
Using hydrogen for fuel has become a lot safer since the 1930s—so much so that it’s now being considered for use in the home. unlike jet aircraft, once airships are aloft they don’t need lots of energy to keep them there. At that point, the energy costs become comparable with rail travel.
Airships won’t get passengers to their destinations very fast—the Hindenburg set the current record for a transatlantic crossing at just under 44 hours—but they do permit time to enjoy stunning vistas. think of them instead as air cruises. in the romantic era of early commercial flight, airships were expected to become “flying hotels” that could accommodate dining rooms and ballroom dances.
There’s one more option, but you might struggle to believe it’s possible within the next thirty years. Still, the materials needed to build it already exist. An orbital ring is a strong steel cable in orbit just above the atmosphere—80km above Earth. It rotates, creating forces which try to make the ring fly apart into space, while gravity tries to pull it down to Earth.
If the ring is spun at the correct speed, the 2 forces balance each other, permitting it to rotate seemingly weightlessly. A “cuff” can be built around the cable which would hold itself in place, unmoving, by magnetic repulsion. The structure would be connected to the ground by cables, with an elevator giving access to the ring in less than an hour.
Two maglev train tracks—which use magnets to move trains along without friction—on the underside of the ring and another on the outside could transport passengers at incredible speeds, reaching the other side of the world in 45 minutes.
If these options sound unrealistic, then bear in mind that our current course of expanding carbon-intensive air travel is unrealistic for avoiding catastrophic climate change. Daring ideas are one thing, we need radical action to revolutionize how we travel the world.