Should we give up flying?

Flying is a highly controversial topic in climate debates. It accounts for around 2.5% of global CO₂ emissions, but 3.5% when we take non-CO₂ impacts on climate into account. As well as emitting CO2 from burning fuel, planes affect the concentration of other gases and pollutants in the atmosphere. They result in a short-term increase, but a long-term decrease in ozone (O3); a decrease in methane (CH4); emissions of water vapor; soot; sulfur aerosols; and water contrails. While some of these impacts result in warming, others induce a cooling effect. Overall, the warming effect is stronger.

David Lee et al. (2020) quantified the overall effect of aviation on global warming when all of these impacts were included. To do this they calculated the so-called. Radiative forcing measures the difference between incoming energy and the energy radiated back to space. If more energy is absorbed than radiated, the atmosphere becomes warmer. 

So when we use planes we are contributing to global warming, but what other options do we have?! Taking into consideration that around 80 percent of people have never set foot on a plane, then who is really responsible? These are the rich people or people who have enough money to afford to step on a plane and go somewhere. We all know that planes enable us to travel faster, but there are also other means of transport that can enable us to reach a place. Emissions from flights stay in the atmosphere and will warm it for several centuries. Because aircraft emissions are released high in the atmosphere, they have a potent climate impact, triggering chemical reactions and atmospheric effects that heat the planet. This is why we should search for other ways of transport, such as trains and busses. Before the pandemic, a “flying shame” movement, which aims to discourage air travel in favor of greener options like rail, was gaining ground globally thanks to Greta Thunberg, a Swedish climate activist. There were early signs that it may have reduced air travel in Germany and Sweden. Now French lawmakers are considering a ban on short flights that can be replaced by train travel.

But their results, which are published in Environmental Research Letters, also show that if we were to reduce air traffic by just 2.5% each year (resulting in about 50% less air traffic by 2050 compared with 2019) then the aviation industry’s contribution to global warming would remain about 0.04C, resulting in a relatively insignificant amount of additional heating between now and 2050.

This is because more than half the warming caused by aircraft comes from the indirect effects – contrails, clouds and chemistry. And the fall in these indirect effects would balance out the warming caused by the continued rise in carbon dioxide.

“Any growth in aviation emissions has a disproportionate impact, causing lots of warming,” said Prof Myles Allen at the University of Oxford, a co-author of the study. “But any decline also has a disproportionate impact in the other direction. So the good news is that we don’t actually need to all stop flying immediately to stop aviation from causing further global warming – but we do clearly need a fundamental change in direction now, and radical innovation in the future.”

The easiest, most obvious thing we can do is to fly less. That's not to say we should never take to the skies again or resort to porridge pics. But it is to say each time we decide not to fly, we are making a positive contribution to slowing global warming. And after a year of being forcibly grounded, we know that not every holiday has to be a plane ride away, or that every international business meeting has to be conducted face-to-face.

Sources used:

https://www.theguardian.com/world/2021/nov/04/small-cuts-in-air-traffic-would-level-off-global-heating-caused-by-flying-study

https://www.nytimes.com/2021/05/28/business/energy-environment/airlines-climate-planes-emissions.html

https://ourworldindata.org/co2-emissions-from-aviation

https://www.nytimes.com/2021/05/28/business/energy-environment/airlines-climate-planes-emissions.html

Photo credits: https://www.deccanherald.com/science-and-environment/climate-change-may-force-airplanes-to-fly-higher-study-1050941.html