Site icon The Carbon Crisis

9.9 Transportation: Aviation

Author: Josiah Becker

ABSTRACT: Global aviation activities are creating immense air pollution, increasing at a consequential rate, and creating unsustainable emissions of CO2.

Image: CC_Pixabay


The central issue with aviation is the carbon dioxide (CO2) emissions produced in the internal combustion engines of aircrafts. In 2018, global CO2 levels resulting from both passenger and freight aviation resulted in an excess of 1 billion tonnes of emissions (Lee et al., 2020). This amount makes up approximately 2.5% of global anthropogenic carbon dioxide emissions (Ritchie, 2020). However, it is more than just carbon dioxide that contributes to overall air pollution and global warming. Substances such as water vapor, nitrous gases, soot, sulphates, ozone, and particulate matters all play a detrimental role as well which increases the contribution of aviation to approximately 5% of the world’s greenhouse gas emissions (EESI, 2019). It is well known that these pollutants (chiefly CO2) act as greenhouse gases, intensify global warming, and result in adverse environmental disturbances. These include, but are not limited to, increased weather extremities (heat waves, hurricanes, floods, etc.), ocean acidification, biodiversity loss, sea level rise, food insecurity, and water scarcity (IPCC, 2018).

Graph 1: Global CO2 emissions from aviation from 1940-2018. (Our World in Data)

While at first glance these statistics don’t appear all too devastating, it is expected that aviation will consume approximately 27% of the 1.5-degree carbon budget by 2050 if practices remain the same (ICAO, 2016). In 2018, the total number of passengers that flew on commercial flights exceeded four billion marking a 6.4% increase from 2017 (ICAO, 2018). With this rapid increase in air travel, there is a wide-spread consensus that the 1.5°C goal will not be achieved if changes toward sustainability in the aviation industry are not made (IPCC, 1999; ICAO, 2016; Alter, 2020; Suzuki, 2021).

Graph 2: Number of passengers on commercial flights from 1970-2018. (CC_The World Bank)

The question then becomes centered around how flying can head in a more sustainable direction. Electric engines, biofuels, and hydrogen fuel cells are the most considered technologies to accomplish this; however, there is a major technological lag with these solutions that make them currently infeasible. Electric batteries are extremely resource intensive, heavy, and are unable to sustain 80% of current flights due to limited charge times (Suzuki, 2021). Biofuels and hydrogen fuel cells provide more promising developments; however, airlines have little to no incentive to invest in these technologies. In this regard, consumers can create change by choosing where to purchase. One largely accepted consumer-oriented method is the implementation of carbon offsets. Carbon offsetting could counteract the individual carbon emissions of a specific flight (or any other activity) but the inevitable difficulty that comes with this is that individuals are forced to pay more. Aside from avoiding flights altogether, consumers can demand that airlines and governments make changes. The COVID-19 pandemic resulting in airline bankruptcies is a potent illustration of just how much influence consumers have over the future of these companies and their practices.


Alter, L. (2020, February 28). You Can’t Live a 1.5 Degree Lifestyle and Get on a Plane.

David Suzuki Foundation. (2021). Air Travel and Climate Change.

Environmental and Energy Study Institute. (2019, October 17). Fact Sheet: The Growth in Greenhouse Gas Emissions from Commercial Aviation. gas-emissions-from-commercial-aviation.

International Civil Aviation Organization. (2016). (rep.). On Board a Sustainable Future: 2016 Environmental Report. ICAO. vironmental%20Report%202016.pdf

International Civil Aviation Organization. (2018). The World of Air Transport in 2018. Uniting Aviation: A United Nations Specialized Agency. rt-in-2018.aspx#:~:text=According%20to%20ICAO’s%20preliminary%20 compilation,a%203.5%20per%20cent%20increase.

International Panel on Climate Change. (1999). (rep.). IPCC Special Report Aviation and the Global Atmosphere. IPCC.

International Panel on Climate Change. (2018). (rep.). Global Warming of 1.5 ºC. IPCC.

Lee, D. S., Fahey, D. W., Skowron, A., Allen, M. R., Burkhardt, U., Chen, Q., Doherty, S. J., Freeman, S., Forster, P. M., Fuglestvedt, J., Gettelman, A., De León, R. R., Lim, L. L., Lund, M. T., Millar, R. J., Owen, B., Penner, J. E., Pitari, G., Prather, M. J., . . . Wilcox, L. J. (2020). The Contribution of Global Aviation to Anthropogenic Climate Forcing for 2000 to 2018. Atmospheric Environment (1994), 244, 117834.

Ritchie, H. (2020, October 22). Climate Change and Flying: What Share of Global CO2 Emissions Come from Aviation? Our World in Data.


Josiah Becker is a fourth-year undergraduate student in the Environment and Urban Sustainability Program at Ryerson University. Throughout his studies, he has taken part in a variety of multidisciplinary courses and has built a foundation in the natural sciences, policy, and environmental studies. He has studied abroad at Wageningen University and Research and takes a particular interest in environmental impact assessment and human-centered urban design.

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