Monday, 13 July 2018 was a day for the record books. On that day the Swedish company FlightRadar24 tracked 205,468 flights occurring around the world, making it aviation’s busiest day in history. It would be a herculean task to determine the total carbon footprint of all those flights put together, but a basic back-of-envelope calculation yields some jaw-dropping figures. Consider that even a one-way short-haul flight in Canada (such as the average 1-hour trip between Ottawa and Toronto) generates about 4718 kilograms of carbon dioxide (CO2) — about as much as a typical passenger vehicle does in a whole year.[1]
If the Ottawa to Toronto route is representative of the global average in terms of distance travelled, aircraft type, and occupancy, then the aviation sector would have consumed the equivalent of over 2.2 million barrels of oil on that single day! By way of comparison, that’s enough energy to power nearly 105,000 North American homes for a whole year! It is so much CO2 that it would require 1.1 million acres of forest a full year to remove it all from the atmosphere.[2] That’s one big day of air travel!
Of course, it’s quite possible that many of the flights tracked were not as damaging, since the tracking software sometimes includes non-commercial small aircraft. But even if we cut that estimate in half, the energy used would still be equivalent to the amount of oil coming out of North Dakota’s Bakken oil fields every day. The point is that any way you look at it, the aviation industry is an unmitigated climate change nightmare. Studies show that global flight emissions alone account for about 2% of all anthropogenic emissions globally.[3] Yet that’s just direct aircraft emissions of CO2. Planes also emit nitrous oxides, water vapour, sulfates, and soot — which also impact the climate.
The Intergovernmental Panel on Climate Change (IPCC) found that in 1992, aviation was responsible for 3.5% of all “anthropogenic radiative forcing” (in other words, 3.5% of human-caused climate change), which was expected to climb to 5% by 2050. But that figure doesn’t even account for the sector’s broader supply chain, which would have to factor in all the energy that goes into building, maintaining, and energizing airports and runways; producing, refining, storing, and transporting jet fuel; and of course, feeding all those hundreds of thousands of daily travellers.
There are no good global estimates of emissions from the entire aviation supply chain out there. However, one study of the life-cycle emissions for the aviation sector in the US found that an equivalent of 30% of aircraft emissionsare generated through indirect categories such as jet fuel production, airport and runway construction, aircraft manufacturing, and so on. If the same is true in global terms, then the aviation sector is responsible for about 4.6% of anthropogenic radiative forcing.
According to the International Civil Aviation Organization (ICAO), there were more than 4 billion air passengers last year. Of course, not everyone in the world flies. In fact, most of the world (80%) has never been on an airplane. And of the remaining 20%, some travel frequently and some travel about once a year. One educated guess is that 6% of the world’s population flies in a given year (as distinct passengers) — so, about 446 million people in 2016. The aviation sector thus has a population akin to that of Indonesia and Nigeria combined, being responsible for about 4.6% of anthropogenic warming.[4]
All of this raises an important question: Why is it that while the world’s biggest oil companies and, more recently, the world’s largest livestock producers, occasionally get lambasted in the media for their willful ignorance on climate change, the world’s biggest airlines do not? While it’s true that there is a growing popular understanding that flying is a “climate negative” behaviour, there is very little sense of how significant the sector is as a contributor to anthropogenic climate change.
More worryingly is how significant it will be according to projections of growing air travel. According to the International Air Transport Association (IATA), air travel is expected to double over the next two decades. So how is the aviation industry avoiding being held to account for climate change?
First, the sector benefits from the publicity received by technological innovations and efficiency gains in aviation — this gives the perception that the corporations that build and operate aircraft, and the governments that regulate them, are taking the necessary steps to tackle the problem. While the idea of electric airplanes is pretty much a non-starter for commercial aviation, there are indeed some recent efficiency and technological gains made by aircraft manufacturers and airline companies. Notably, these include the growing use of biofuels, new lightweight materials being used on airplanes, and improvements in air traffic management (all of which help reduce emissions).
Combined with the rise of “offset” products, these innovations give the false impression that aviation emissions are under control. But nothing could be further from the truth. For instance, the sector’s target of 1.5% fuel efficiency improvements per year between 2009 and 2020 are clearly being overwhelmed by the annual growth in passenger demand, which has hovered at around 6% per year. Improvements in efficiency are certainly helpful, but they are simply not keeping up with the growing pace of emissions.
The second reason relates to problems with the IPCC reporting mechanisms for aviation emissions. Because of the international nature of aviation vis-a-vis the nation-based reporting to the IPCC, countries submit figures for domestic and international aviation separately. In part, this is borne of a methodological dispute over who ought to take the emissions burden in their national greenhouse gas (GHG) reports.
For instance, should emissions for an international flight be split 50/50 between the countries of departure and arrival? What if the majority of the flight occurs over one country, or if the majority of passengers are from another — should those countries report a higher share of the flight emissions? Or, should the emissions be attributed to the country where the airplane fuelled-up?
The problem with this dual-reporting mechanism is that emissions figures often end up being downplayed. For instance, a 2012 government reportentitled Canada’s Action Plan to Reduce Greenhouse Gas Emissions from Aviation claims that only around 5% of transport emissions (about 1% of national emissions) are due to aviation. But that figure only includes domesticaviation. A deeper dive into Canada’s National Inventory Report to the United Nations Framework Convention on Climate Change (hiding somewhere on page 88) shows that when international travel is included, aviation is actually responsible for 11% of transport sector emissions, or 2.7% of the country’s total emissions. In the end, the ability of aviation — like global shipping — to sneak out of national reporting has helped the sector fly under the radar at the national level, since domestically oriented policies try to identify and reduce GHG emissions from the most polluting sectors.
Finally, there’s CORSIA — the Carbon Offsetting and Reduction Scheme for International Aviation. This is the global aviation industry’s ambitious plan for addressing climate change. According to CORSIA, the aviation sector has less than a decade to cap and reduce its flight emissions to 2020 levels, and then by 2050 it aims to bring them down an additional 50% compared to 2005 levels. While that would indeed mark a substantial reduction, the likelihood of it being achieved is extremely low. So much of CORSIA relies on what it calls a “Global Market-Based Measure” (MBM) — essentially a global-scale carbon fee that most nations would have to agree to that would go towards offsetting the projected growth in international emissions relative to 2020.
Obviously, the plan to implement a global MBM is riddled with problems. Not only does it require the international community to co-operate on the implementation of new carbon pricing (a political policy wedge in countless industrialized nations today), but it also assumes problematically that carbon offsets work in the first place. As one expert explains, “offsetting is worse than doing nothing. It is without scientific legitimacy, is dangerously misleading, and almost certainly contributes to a net increase in the absolute rate of global emissions growth.”
Ultimately, like the publicity around new technologies in aviation efficiencies, CORSIA gives the impression that the problem is being addressed, when clearly it is getting worse. Even if the CORSIA plan reached its objectives of 50% of 2005 emissions by 2050, the sector would still be contributing about 857 Mt of CO2 by mid-century (about as much as Germany emits today) — meaning that the aviation sector alone would be eating up 12% of the global carbon budget for 1.5⁰ C of warming.
In the end, we are left with the classic challenge of trying to balance the benefits of global aviation (and I’ll be the first to admit there are many) with the extreme scale of damage caused by the industry. It’s hard to imagine giving up flying in this fast-paced, integrated, modern world. Perhaps a good starting point is to consider the merits of tackling growth in aviation, which ultimately means coming up with concrete ways to fly less overall.
Until the aviation industry is held to account for its contribution to climate change, the band-aid solutions of trying to minimize the impact of this booming sector will continue to allow it to fly under the radar.
[1] According to ICAO, the average aircraft on that route burns 1866 kg (493 gallons) of aviation fuel during the trip. According to the Energy Information Administration (EIA), jet fuel emits 9.57 kg of CO2 per gallon. So, the average Ottawa–Toronto flight emits 4718 kg of CO2 (4.718 Metric Tons).
[2] These conversion factors all come from the EPA’s “Greenhouse Gas Equivalencies Calculator” — using a value of 969,398 Metric Tons (Mt) of CO2(4.718 Mt x 205,468).
[3] According to the ICAO, the international component of the sector emitted 448 Mt CO2 from direct fuel consumption in 2010. The ICAO also notes that international aviation accounts for 65% of global aviation fuel consumption, meaning that another 241 Mt CO2 is emitted from domestic aviation. Together, 689 Mt CO2 is equivalent to 1.4% of global anthropogenic emissions in 2010 according to the IPCC. According to IATA, air transport accounted for 2% of anthropogenic emissions in 2017 (about 859 Mt of CO2).
[4] In reality, those two countries combined only produce about 2.3% of global emissions.
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