Life | Sustainability
Environmental cost of your holiday
Taking a step back to think before we start flying again
In human history, air travel has been one of the greatest innovations that we have developed. It allows us to travel a great distance, connecting the world and making it a smaller place. We can now easily travel from London to Sydney on a 19 hours non-stop direct flight. Imagine if we still had to travel by water using ships, it would not take us days but weeks on end.
Commercial air travel started around the 1920s — for the first time manufactured aircraft were being used exclusively for transporting commercial passengers. But with this wonderful innovation of connecting people and continents, it came with a cost — increase in carbon emission to the environment.
I’ve worked in the aviation industry for 5+ years and would like to share the knowledge of the carbon emission we produce when taking a flight and what can we do about it. This will help us as consumers to be more informed and know that the decision we make has a lasting impact on the environment.
Understanding carbon emission from aircraft
Aircraft are like cars, we use fuel (in this case jet fuel/kerosene) and the engine produces “work”. In the car’s case, your wheels start moving and you get to travel along the road. Similarly in an aircraft when the combustion happens, a lot of air moves through its engine to get thrust which allows the aircraft to move forward.
Through this combustion process during aircraft operation, the main emissions that are exhausted from the engine are carbon dioxide (CO2), nitrogen oxides (NOX), sulphur oxides (SOX), unburnt hydrocarbons (HC), carbon monoxide (CO), particulate matter (PM) and soot.
Researchers (Lee et al. 2009) studied and measured these emissions and came up with a simpler way of portraying these emissions — CO2 equivalent. This is meant to help us understand carbon emission better by converting all the other emissions mentioned above into the equivalent of CO2 emissions. The amount of aircraft emissions is calculated from the fuel burned, so if more fuel was used during a flight, more CO2-equivalent emissions are emitted.
More efficient aircraft = less carbon emission
Today, the world’s most widely used jet aircraft is the Boeing 737. The first commercial version, the Boeing 737–100, took to the skies for the first time in 1967 and could carry 124 passengers over 2,775km (1,724 miles, barely able to fly from Los Angeles to Chicago).
The latest generation Airbus A320 is more fuel-efficient to operate than the previous generations of narrow-body aircraft it replaced. In fact, Airbus spends more than $260 million per annum on research and development in further improving the efficiency of the A320 family of aircraft.
This means that with the same amount of fuel we get to travel further and lowers per passenger emissions. But a more efficient aircraft throughout the last 50 years has also created a big boom in the travel industry and as a result, more people are traveling using air travel for its convenience which significantly increased the absolute amount of carbon emissions emitted to the atmosphere.
Understanding the carbon cycle
Before we can understand the impact of our carbon emission when we take a flight, we need to know more about the carbon. Carbon is essential for life. On earth, we eat carbon, use carbon, and are made up of carbon atoms. Most carbon is stored in rocks and sediments, while the rest is located in the ocean, atmosphere, and living organisms. These are the reservoirs, or sinks, through which carbon cycles.
The carbon cycle describes the process in which carbon moves from the atmosphere to the ground and then back into the atmosphere. Since the earth is a closed environment, the amount of carbon in this system does not change. Where the carbon is located — in the atmosphere or on the ground — is constantly changing.
Carbon is released back into the atmosphere when organisms die, volcanoes erupt, fires blaze, fossil fuels are burned (jet fuel in this case), and through a variety of other mechanisms.
To capture carbon that is in the atmosphere, trees are still the most efficient method to recapture carbon from CO2 through the process of photosynthesis. The trees or plant biomass — the majority in trunk and roots — is where the captured carbon is stored. When we cut trees down, all that stored carbon is eventually released back to the atmosphere.
So when we take a flight that burns fossil fuel, we release carbon that was trap in the fuel (hydrocarbons) back to the atmosphere. And to recapture carbon, it seems it is just as simple as planting trees. Over the last few decades, there have been big tree planting projects — and this has definitely helped to rein in some of the carbon emission that we have produced, but we can do more.
Your carbon emission and your impact
Most airlines if not all, are not required to price in the cost of carbon emission into their ticket. But that is similar to most consumer products, do we pay extra for the cost of carbon emission when we eat beef? While living in the current capitalist model does not account for the cost of carbon emission, we as the consumer can be more aware and be informed.
There are various online carbon emission calculator to check the amount of CO2 produced when you travel, but it is best to use the carbon emission calculator from the airline you traveled. Most airlines have signed up with international environmental bodies to create and provide an accurate carbon emission calculator to inform customers about their carbon emission.
My most recent one-way travel from New Zealand to the United Kingdom by air is estimated to have produced 1409 kg of CO2 equivalent emission.
Assuming that for every 1 tree will sequester approximately 5kg of CO2 in biomass over a year, if I were to offset or try to recapture the 1409 kg of CO2 equivalent emission, I will need to plant 15 trees and allow it to grow for the next 20 years just to recapture the CO2 of the single flight I have taken. Also after the trees have grown up to 20 years old, I can’t cut them down and use it, because if it is used the carbon is released back to the environment. The other thing to note about trees is that during its life span, it recaptures CO2 at different rates — during the first few years, it actually captures a lot less.
If I plan to travel just between New Zealand and the United Kingdom every year, round trip, I will need to plant approximately 300 square meters (3230 square feet) of trees every single year — that is about 1.2x the typical US single-family detached home. Imagine the cost of owning or renting the land just for the trees to grow. The cost of maintaining and caring for those trees.
This is the cost of CO2 emission that we are not paying today when we fly, but while we are not paying for it right now, future generations — our kids, our great-grandkids will be paying for it their health and they will see the environmental impact of our decision.
There are many ways you can offset your carbon emission when you fly, but what I found best is to go through your airline and offset using their scheme. Most airlines have partnered up with forestries and non-profit environmental groups to plant forest that focuses on recapturing carbon.
So, how bad is this carbon dioxide emission? while CO2 in itself is neither good nor bad. Having a lot more CO2 in our atmosphere is bad because it increases the greenhouse effect which makes our earth more warmer. And an uncontrolled warming of the earth will have a serious impact on all life on earth.
I hope that you are now a more informed consumer and do think twice before planning that vacation. If all of us do our part, we can make the world a better place for future generations.
Before you go…
If you found this article helpful, and like to read more about this kind of article feel free to drop a comment.
