If you’ve taken a commercial flight, you’ve probably heard the pilot or lead flight attendant call out “prepare for crosscheck.” It’s code for “before the plane can take off, arm the doors to allow the safety slides to deploy in an emergency.” Start-up companies are designing new supersonic jets, but they must follow good procedure and complete an “environmental crosscheck,” so they meet current environmental standards to safeguard people’s health and the climate.
Supersonic flight has captivated our collective imagination ever since the Concorde made its maiden commercial voyage in 1976. It’s easy to see why. Anyone who has ever travelled from New York to London would gladly make the trip in half the time if it were possible. Of course, the last flight of the Concorde took place in 2003 largely because it was no longer economically viable.
But now a new effort led by supersonic start-ups Spike Aerospace, Aerion Corporation, and Boom Technology with support from businesses like Lockheed Martin and Virgin Group is underway to bring supersonic flight back to the marketplace. As the public assesses the prospect of supersonic flight once more, it’s essential that it also consider the impacts of this technology, including those on our climate.
The air transportation sector is poised to consume a quarter of the world’s 1.5-degree carbon budget by 2050. If commercial supersonic planes again take to the skies, they would eat up an even greater share. Traveling faster than the speed of sound — while glamorous — is estimated to emit at least 5 to 7 times as much carbon dioxide per passenger compared to subsonic aircraft, according to a new working paper published today by the International Council on Clean Transportation (ICCT). For this reason, it is vital that any new supersonic aircraft meet existing international emissions efficiency standards set for sub-sonic airplanes — our climate depends upon it.
That might be hard to achieve: ICCT’s modelling estimates that commercial supersonic planes could fail the international nitrogen oxide (NOx) standard by 40% and the carbon dioxide (CO2) standard by 70%. Noise pollution is also of mounting concern, and ICCT projects that supersonic planes would also not pass existing noise standards.
Policy discussions on supersonics are happening now at the United Nations specialized aviation agency and in the United States’ Government about whether to develop noise and emissions standards for supersonic aircraft. Unfortunately, an amendment to the U.S. Federal Aviation Administration (FAA) reauthorization bill — the Lee-Gardner Amendment — would likely lead to weakened noise standards for supersonic flights, incentivizing development of supersonic aircraft with unacceptably low environmental performance. Meanwhile, other European countries believe that current limits on aircraft noise should be the “guidelines” for creating landing and take-off standards.
The aviation industry can continue to be an engine for innovation for the global economy and connect people, but it should strive to do so within scientifically recognized environmental limits. There are more promising innovations to pursue that will allow aviation the license to operate sustainably throughout the 21st century, instead of investing billions in a decades-old technology that already failed the Concorde.
Aviation breakthroughs already making headway include the development of electric and hybrid planes, and low-carbon fuels. Start-up Zunum has already begun developing hybrid and electric aircraft. Researchers are also working towards commercializing liquid fuels derived from water, CO2 and renewable electricity — called “power-to-liquids” or “electrofuels”. These fuels can be developed with up to 99% fewer emissions being released in the process of their creation, and thus could be an emerging solution to aviation’s growing carbon footprint.
Let’s establish aviation policies that incentivize these new breakthroughs instead of allowing weaker standards for older, dirtier technologies like supersonic aircraft. Current standards for aviation already represent a low bar given that carbon pollution from international aviation is one of the fastest-growing sources of the greenhouse gas emissions driving global climate change. If supersonic aircraft want to lift off again, they’ll have to pass an environmental cross-check first.
