This is the worst time to be excited about supersonic flight

Sounds fast.
Sounds fast.
Image: REUTERS/Christopher Pasatieri
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Blake Scholl has a vision. The former pilot and CEO of aircraft company Boom Supersonic wants “supersonic everywhere:” tens of millions of people each year rocketing around the world at a speed faster than sound.

The company hopes to be not just airborne but fully operational by the mid-to-late 2020s. Initially, Boom intends its planes to fly more than 500 viable over-water routes. Passengers could hop from New York to London in three hours and 15 minutes, rather than the customary seven, or from Los Angeles to Sydney (with a stop) in 6 hours 45 minutes. (At the moment, the journey is a marathon 15 hours, non-stop.) In the more distant future, Scholl wants travelers zipping overland too, on journeys like Los Angeles to Washington, DC, in two hours flat.

Boom’s planned Overture jet, designed to carry 55 passengers, has a proposed max speed of 1,688 miles per hour, or 2.2 times the speed of sound. At $5,000 for a London-New York return flight, tickets would initially be competitive with subsonic business class, perhaps eventually becoming as cheap as economy.

In so many respects, now is the best-ever time for supersonic flight, Scholl said: “There are actually no barriers, not technologically, not in the market, not even in regulation,” he told an audience at an event hosted by the Washington Post in New York last week. Boom’s aircraft, which will begin test flights next year, have been developed with input from the FAA, he said, hopefully permitting a certification process far quicker than the ordinary five year wait. “What we’re finding now is we’re finally at the intersection of what’s practical—technologically—and what’s economical for airlines, and for the flying public.”

Not since the demise of the Concorde—the transatlantic faster-than-sound plane grounded in 2013 over profitability and safety concerns— has there been this much excitement about supersonic flight. The Federal Aviation Administration Reauthorization Act, signed by US president Donald Trump in 2018, has a special focus on the “safe and efficient operation of civil supersonic aircraft.” Lockheed Martin is building a plane for NASA capable of quiet overland supersonic flight, while other US firms such as Spike and Aerion are quietly optimistic about their ability to get their planes into the sky by 2025 at the latest. (Boeing signed a development deal with Aerion in February—but also released concept images last year for a hypersonic plane all of its own, to be released in 20 to 30 years.) The market’s interest is also piqued: Colorado-based Boom has already raised more than $140 million, including $10 million from Japan Airlines, which has the option to purchase up to 20 Overture jets.

But while Scholl may be making plans for a future in which three-hour transatlantic hops are actually the cheapest option, now seems like a terrible time to be pouring resources into supersonic flight.

A climate problem

Without extremely dramatic reduction in their carbon emissions, almost every country in the world is going to miss the goals set out by the Paris Climate Accord by a significant margin. Countries that have not signed it at all, including the US, will sail straight past them. Supersonic flight wouldn’t just be another way to get around the world, but another way to trash the planet, very quickly.

The engines currently under development would burn five-to-seven times more fuel per passenger than subsonic jets, according to International Council on Clean Transportation (ICCT) estimates, exceeding current subsonic limits for nitrogen oxide and carbon dioxide by 40% and 70% respectively. The why isn’t all that complicated: Flying faster burns more fuel, releasing more emissions, while a cruise height above 50,000 feet means that sooty carbon deposits may linger in the upper stratosphere for months or years at a time.

Suppose the world does embrace supersonic flight all over again. By 2035, according to a January ICCT paper, we might have 2,000 supersonic aircrafts, taking around 5,000 flights a day. (At the moment, there are over 100,000 subsonic flights daily.) Each year, this fleet of planes would emit approximately 100 million metric tons of CO2 per year. In context, that’s roughly the annual combined emissions of American, Delta, and Southwest Airlines, or approximately 20% of aviation’s entire carbon budget worldwide.

Leaders in the sector are already pushing for supersonic-specific environmental standards of their own, which would be more permissive than for ordinary commercial aircrafts. But acknowledging that these planes are necessarily bigger polluters—Aerion’s chief sustainability officer Gene Holloway chalks it up to “the laws of physics”—doesn’t get away from the fact that, right now, we have little budget for brand new emissions.

Boom, for its part, believes there’s a sustainable way to make supersonic flights work, including keeping fuel burn to roughly the same level as commercial business class—or about two to three times as emission-intensive per passenger as economy class. “We are committed to pushing the envelope to discover new ways to make supersonic travel environmentally and socially sustainable for generations to come,” Dan Mahoney, a Boom spokesperson, told USA Today.

Equitable emissions

Perhaps more important is the political message.

In the past year, climate protests have proliferated worldwide, resulting in the UK declaring an official climate emergency. Pushing supersonic flight right now seems more than a little tone-deaf.

To meet their targets and minimize potential warming, countries must take a proactive approach to adopting lower-emission infrastructure. On an individual level, voters need to support politicians who want to rein in corporate emissions—even if it comes at a cost to taxpayers. They may also have to adopt a less carbon-heavy lifestyle. Research suggests that people may not be prepared to do their bit if it seems unfair, or if everyone is not playing their part. The “tens of millions” of prospective supersonic flyers each year would represent some of the world’s richest people, taking far more than their fair share of the emissions pie. Already, climate change affects human beings unevenly, with the poorest shouldering much of the load. Giving the rich a highly efficient, new way to pollute completely undermines any hope of at least the illusion of equity.