The Royal Society of Edinburgh, Scotland’s National Academy, is holding a free event this September to discuss the difficult but critical task of decarbonising aviation as part of its flagship event series Curious.

Curious – running from 4-17 September this year – is a completely free and open series of tours, talks and workshops that brings together some of Scotland’s finest minds in various academic fields with the aim of getting under the surface of some of the most important issues of the day.

Andrew Rae, professor of engineering at the University of the Highlands and Islands, will give an online talk outlining some of the challenges with making air transport a greener industry and discussing some of the cutting-edge work taking place in aviation.

Professor Rae said: “Obviously with the climate emergency there is a need to reduce carbon emissions from aircraft – and although air transport is a relatively small fraction of the transport around the world its significant in where the emissions take place.”

Particulates left at altitude, and the fact that air transport has increased over time and still increases, make aviation an important industry to focus on decarbonising. There has until recently been a focus on making flying cheaper by making aircraft more fuel-efficient, but now that is shifting towards alternative fuels too, Professor Rae said.

He added: “There is a need to do something different, and that means replacing the standard fossil fuels with alternatives, and at the moment those alternatives are things like electric battery power, hydrogen, or sustainable aviation fuel which behaves in the same way as fossil fuel but it comes from sustainable sources.

The problem with all of these alternatives is that none of them are perfect.

“Batteries are heavy, hydrogen is tricky, and sustainable aviation fuel will still – although there is less carbon – emit particles into the atmosphere which can promote cloud formation for example, which contributes one way or another to climate change,” Professor Rae said.

However, work is ongoing at Orkney’s Sustainable Aviation Test Environment (SATE) to develop environmentally friendly methods of air transport.

A man wearing a suit and tie smiling at the camera
Professor Andrew Rae

He added: “In Orkney you’ve got the inter-island flights as well as the connections to the mainland. It’s a relatively quiet airport but it’s got all of the types of aviation that a big airport like Heathrow has, so you can test all of the relevant technologies, but in a less congested atmosphere.”

Harsh weather, high winds and the pressure on resilience of vital services also make Orkney an ideal proving ground for the future of flight. With governments setting targets for net-zero emission, time is short to meet this critical engineering challenge.

“I work quite a lot in schools and I say to the students who are interested, I hope that if they choose aviation and they get to the point in their career that I am at now, they will look back at what we are doing and laugh, because they will have come up with a much, much better way of doing it. 

“But you’ve got to start somewhere,” Professor Rae said.

Despite the challenges that face the industry, the appetite to make change is there. People will have the chance to learn about the details of the future of aviation without carbon emissions – for free – from the people who are working on this new frontier.

Professor Rae said: “I hope people will come away from our Curious event knowing that there are people trying to do something about decarbonising aviation, but also that there is no easy solution.

“It’s not just people talking. Real aircraft are being built, and tested, against real-world use cases. It’s not just pushing technology for the sake of it, it’s crucial both from an environmental and a community resilience point of view.”

Professor Rae’s event No silver bullet: decarbonising aviation will be held online on September 13 at 3pm and is free and open to all. Visit for more information and to book your place.