Industry Insights with Joachim Majholm, Blue Lines - Climate impact opportunities of non-CO2
Joachim Majholm
Founder & Contrails Expert
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Blue Lines
In this interview, Joachim Majholm, the Founder of Blue Lines, and an expert on contrails, shares his insights on contrails: what are they, what is their impact, and how easily can they be managed? It turns out, potentially quite easily!
Can you start by telling us a bit about yourself, and about Blue Lines?
Absolutely. My interest in sustainable aviation was sparked during COVID-19 when I began educating myself on all the different climate solutions to stop global warming. One day I happened to be introduced to a group of scientists and engineers working on something called “contrail avoidance”, which I had never heard about before. They needed help with strategy and communicating their complicated work so everybody could understand. My background is in business and communication, so I helped them out for three months, but afterward I could not forget this unique climate opportunity of tactical contrail avoidance, so I decided to found my own non-profit called Blue Lines, dedicated to implementing contrail management as a climate solution worldwide.
Aviation decarbonization won’t be a new topic to anyone reading, but non-CO2 emissions have only begun being explored more recently. Can you give us an overview of what they are, and the latest understanding of their impact?
The non-CO2 effects of aviation consist of NOx emissions, water vapor emissions, aerosol-radiation and aerosol-cloud interactions from soot and sulfur, and the impact from contrails. In 1999, the Intergovernmental Panel on Climate Change (IPCC) wrote about the climate impact of aviation’s non-CO2 effects for the first time. While we are relatively confident about CO2’s climate effect, there is a lot of uncertainty connected with the size of the non-CO2 effects. However, contrails seem to have the most significant impact of them all. Since the birth of commercial aviation, the historic warming impact of contrails could be anywhere from around half to more than 2.5 times more warming than all the combined CO2 from aviation in the atmosphere since 1940. This means that the contrail clouds being created now are likely to warm the planet more now than all the CO2 emissions from aircraft accumulated over the past 80 years.
How big of an opportunity for reducing aviation’s climate impact does contrail management offer?
It is difficult to determine the exact potential for climate savings here. We know that CO2 emissions have a very low warming potential, but since CO2 stays in the atmosphere for centuries or millennia, the warming will accumulate significantly over time. Contrails are directly opposite. Contrail clouds have a very high warming potential, but after a few hours, when the contrail clouds disappear, so does their climate effect. So, when we limit CO2 emissions, we will not see the full impact of that removed CO2 for centuries, but if we remove warming contrails, it will have an immediate cooling effect on the planet, which is something we need to avoid irreversible tipping points and to keep global warming under 1.5 degrees according to the Paris agreement. When all this is said, efforts to reduce the non-CO2 effects of aviation must never come at the expense of efforts to decarbonize aviation. Both are extremely important and should not be seen as trade-offs. We should work to bring down both CO2 emissions and non-CO2 effects in parallel.
How do you hope to see the industry working to tackle this? What solutions for contrail management are there?
This is where it gets really interesting because removing warming contrails looks to be relatively easy, cheap, and non-intrusive. If we can predict where the pockets of very cold and very humid air are, we can lead aircraft around those areas and avoid creating warming contrails. We already do something similar when aircraft fly around areas with a lot of turbulence. It does cost a little more in extra fuel burn (and associated CO2 emissions) to avoid these areas, but we only need to redirect roughly 5% of flights to reduce about 80% of contrail warming. The models to predict where contrails will appear are not perfect, but they are improving rapidly. What we need the industry to do is to support large-scale trials and simulations so that we can work out all the kinks before contrail avoidance is scaled up. Besides airlines participating in large trials, other crucial collaborators are within air space management. ATC may limit passage through highly warming contrail areas in the future.
You will be chairing the non-CO2 stream at the upcoming Sustainable Aviation Futures North America Congress, and sharing more information in one of the panels. What are you most looking forward to at the event?
I look forward to learning from all the non-CO2 stream sessions and sharing the latest developments within non-CO2 with aviation folks at the conference. Some exciting people are participating in the stream, starting with leaders from Google Research and Bill Gates’s Breakthrough Energy, who will share their contrail knowledge.
Besides the sessions, I always enjoy meeting new and old people during the breaks and learning other perspectives on aviation and sustainability. The superpower of a physical conference is connecting with people we wouldn’t otherwise have met. So, if you see a very tall guy with brown hair and glasses during coffee breaks, come over and chat – I’d love to meet everyone.
Would you like hear more about non-CO2’s climate impact and management, and gain additional insights from Blue Lines?