Can aviation become sustainable one day? – 08/10/2023 – Market

Flying is an important part of many people’s lives — but experts warn that you have to balance that with the fact that the industry is a huge contributor to global warming.

About 2.4% of global CO2 emissions come from aviation. Together with other gases and the trailing water vapor produced by aircraft, industry is responsible for about 5% of global warming.

And emissions from planes are rising fast — they grew by 32% between 2013 and 2018.

A round-trip flight from London to San Francisco (a similar distance to São Paulo to Barcelona, ​​or Rio de Janeiro to Chicago) emits about 5.5 tonnes of CO2 equivalent per person—more than twice as much as emissions produced by a family car in a year and around half the average carbon footprint of someone living in the UK.

Experts say that humanity has allowed the sector’s emissions situation to deteriorate for too long.

There is now a very short window within which to reduce this sector’s emissions to almost zero.

“There are two main reasons why aviation presents a unique challenge in terms of climate change,” says Cait Hewitt, director of policy for the Aviation Environment Federation, a non-governmental organization working to mitigate aviation’s impact on the environment.

“The first is that more and more people are flying. And the second is that flying remains almost entirely dependent on fossil fuels. We still don’t have green technologies available for the aviation industry.”

In 2019, aviation produced a gigaton of CO2 emissions.

“That’s roughly equivalent to the total emissions of the UK and Germany combined,” says Hewitt.

The number of passengers continues to grow. In 2019, airlines carried around 4.5 billion passengers.

By 2050, some projections show that the number should reach 10 billion per year.

But not everyone on the planet flies.

“Globally, just 1% of the population, many of whom are frequent flyers, generate half of all aviation industry emissions,” says Hewitt.

The disparity is great. In high-income countries, 40% of the population takes at least one flight per year, while in low-income countries this percentage is only 1% of the population.

“There is no silver bullet for making aviation more environmentally friendly, but rather a set of different options, each with its pros and cons,” says Beth Barker, project manager for the Aviation Impact Accelerator at the University of Cambridge.

Check below some of the measures that experts discuss to reduce emissions in the aviation sector.

1. Design tweaks

One of the alternatives already adopted is modifications in the design of aircraft, such as the adoption of “winglets”.

“Winglets are vertical-looking extensions that we add to the end of the wings,” says Silvestre Pinho, from the Department of Aeronautics at Imperial College London.

“They increase the efficiency of the wings. These winglets were inspired by birds and we are currently looking at many more bird wing and flight features and incorporating them into our aircraft.”

The aviation industry is constantly finding ways to improve aircraft efficiency with design innovations. But there is a limit to this.

“If you look at history, we are improving the efficiency of our aircraft by around 2% per year. This is very little and it will not be sustained forever, so we definitely need to change our aircraft fuels”, says Pinho.

2. Alternative fuels

Currently, aircraft engines run on fuel made from fossil fuels. But there is a rush to look for alternatives.

“Biofuels are a form of fuel produced from materials of plant origin. The only possible example is vegetable oil, which exists in large quantities and can be transformed into biofuel”, says Pinho.

But producing biofuels is a big challenge for the industry.

For example, if we replaced all the jet fuel used in the UK with biofuels, we would be using around 68% of the land we currently use to grow our food.

Another possibility is to use “e-fuels”, which remove carbon dioxide from the air and submit it to chemical processes that transform it back into aviation fuel.

It’s kind of a circular process where everything goes into the atmosphere and then it’s taken out.

“A major disadvantage of e-fuels is that they are very expensive, not only because of the cost, but also because of the energy they consume”, says Pinho.

Another possible fuel would be hydrogen. But there are also challenges in this field.

“Hydrogen is a gas that, if you react with the oxygen in the air, can release a lot of energy. That potentially makes it a really good aviation fuel, but it also has problems,” says Guy Gratton, who is a pilot and professor of aviation. from Cranfield University, UK.

“For starters, we can’t store it in current aircraft designs. Second, about 95% of our hydrogen right now comes from fossil fuels.”

“Hydrogen is very explosive, which imposes serious safety restrictions”, says Pinho.

“Designing, manufacturing and licensing hydrogen-powered aircraft is likely to take decades and cost some tens of billions of pounds.”

3. Can planes become electric?

Electric planes, powered by batteries, are still very rare.

“I’m one of the few people in the world who’s had the chance to fly an electric plane,” says Gratton.

“While it’s possible to make a well-functioning electric car, if you put that same type of battery in an airplane, it would be too heavy to fly.”

Experts say that making aviation sustainable will require a lot of investment in the future.

“There’s no question it will take a lot of resources, especially energy. It’s going to be very costly and it’s going to take a lot of effort from business and government working together,” says Beth Barker.

Text based on original BBC Ideas video. Originally published here.