The reduction of air travel in small amounts every year
Milan Klower receives support from Britain’s Natural Environmental Research Council, the Copernicus Programme of the European Commission, and the European Research Council.
Before the outbreak, the engines of aircraft burned 1 billion litres of fuel per day. Then, the number of daily flights in civil aviation fell between 110,000 to fewer than 50,000 by 2020, on the average. In light of the ease in travel restrictions, air travel is increasing towards the pre-pandemic levels.
Many world leaders and delegatesdelegates will have traveled to Glasgow to participate in COP26, the 26th UN climate change summit in person. However, as they debate emission targets that reduce global warming by 1.5degC instead of 3 degrees Celsius or more,, the aviation industry is unlikely to be included because of the absence of low carbon alternatives for long-haul flights.
But it shouldn’t be. In the latest research with my colleagues, I estimated that if the aviation industry continues to expand at the current rate,, jet fuel consumption will add 0.1@C in global temperature by the year 2050. This is 50% of it and the rest over the coming three decades.
The aviation industry is responsible for 4 percent of the 1.2degC increase in global mean temperature that we have seen during the Industrial Revolution. If we do not take action to cut down on flights, this sector will be responsible for one-third of 0.3degC remaining in the 1.5degC temperature goal as well as 6 percent of the 0.8degC remaining to stay in a range of 2 degrees Celsius. The airlines contribute more carbon dioxide to the atmosphere than most countries.
Warming footprints
At the rate we are at, the Earth is expected to have warmed up by 2 degrees within the next three years. To assess how different activities contribute to warming, scientists study carbon emissions. This is because the amount that the Earth gets warmer is inversely proportional to the cumulative carbon dioxide emissions in the atmosphere. This is an excellent estimation in many instances but is not true regarding emissions from airplanes that travel at altitudes of 12 to 12 kilometers.
In addition to the CO2, aircraft engines emit Nitrogen oxides and water vapor sulfur and soot, which can cause contrail clouds of cirrus and other complex chemical reactions in the air. The sum of these non-CO2 induced effects generates more heat in addition to CO2 emissions. The total footprint of warming caused by aviation is between two and three times more than the carbon footprint that is conventionally used.
Condensation trails caused by engines in aircraft are a significant contributor to global warming. MichaelGaida/Pixabay, CC BY
Although a substantial portion of the CO2 emissions from a flight remains in the air for thousands of years, the effects of non-CO2 decrease as time passes, vanishing within about ten years. Thus, any growth in aviation, as measured by the consumption of jet fuel globally, is a more significant effect as the CO2 and non-CO2 impact increase.
However, a decrease in the aviation industry can partially slow warming since the non-CO2 effects fade in time until only CO2 effects persist. Imagine the non-CO2 effects as bathtubs – they fill with water when taps are turned on further and further, despite a steady discharge from the plughole. However, the same bathtub will eventually be empty if the faucets are slowly turned down.
The non-CO2 impacts of flights on the Earth’s atmosphere will gradually disappear if fewer or fewer flight hours are made, and aviation’s contribution to warming eventually decreases. In this scenario, the growth in CO2 emissions would offset the reduction in non-CO2 effects. Even though aviation could continue to contribute to warming, the total warming caused by both would be constant as time passes. How much does aviation require to shrink to lessen its impact on global warming?
Our research shows that flying doesn’t need to stop right away to prevent the contribution of aviation to global warming from growing. The impact of flight has already led to 0.04degC of warming. With a reduction of 2.5 percent in jet fuel consumption, which is currently only possible through reductions in the flow of air traffic, this warming will slow to an average rate over the following decades.
Do we need to fly?
COVID-19 has had a significant impact on aviation. Air traffic is about 10-20% lower than pre-pandemic levels; however, it is recovering quickly. The government should move subsidies away towards more environmentally sustainable methods of transport, including trains. There is a lot more to be done.
Changes in the way people fly caused by the pandemic have resulted in some people having to reduce flights.
Lockdowns and the transition to remote work have made several people reconsider the need for flying. People deciding to reduce their travel will significantly reduce the number of unnecessary trips. Whenever feasible, In-person and virtual participation in hybrid meetings is an excellent method to help support this shift.
The reduction in the space that passengers of business class take up on planes is another way to reduce flight times because it lets more passengers be on one flight.
The decision not to allow airport expansions could also have a significant impact. The United Kingdom has a Climate Change Committee, an expert body that advises the UK government on climate change. It has recommended not to expand airports to ensure they align with the climate goals. But it is believed that the development of Heathrow Airport is being planned for the future.