In February 2020, a coalition of airlines, airports, and manufacturers known as UK Sustainable Aviation announced they were committing to achieving net-zero carbon emissions by the year 2050 (1)(2). Their claim is ambitious yet not impossible, and the move is a major step—if thus far only a symbolic one—in transitioning the transportation industry towards climate-friendly and sustainable operations. Indeed, decarbonizing transport and the supply chain is the crux of minimizing lifecycle emissions—that is, ensuring that the entire value chain of the products we consume and the services we use, from the sourcing of raw materials to manufacturing to packaging and shipment, is completely carbon neutral. This lifecycle framework is essential in thinking about reaching net-zero because there are naturally going to be some industries and processes that are far harder to decarbonize than others, and succeeding in net-zero emissions requires a unified and concerted effort by all stakeholders globally.
While decarbonization plans vary in the details, many of them have several key principles in common, such as efforts to reduce sales of internal combustion engine-powered vehicles to zero within the next ten to fifteen years, implementation of as many alternative fuels as possible in heavy transport, and smarter urban planning that is tailored towards incentivizing “mobility-as-a-service” and reduced use of personal vehicles.
The first factor is imperative. A policy blog published in 2020 by the University of California, Davis Institute of Transportation Studies emphasizes that “the No. 1 strategy for transportation, dwarfing all others, is definitive: electrify nearly all cars, trucks, and buses while transitioning the electricity sector to zero-emission energy. All other strategies pale in comparison” (3). Moving all personal transport and energy consumption to electricity and renewable sources will relieve an enormous burden from decarbonization efforts, and it is especially critical given that heavier forms of transport—aviation and maritime—will not be able to go fully electric and instead rely on sustainable forms of biofuel that still result in carbon emissions.
However, there is a catch. When it comes to the large-scale transition to EVs, the two primary concerns are the high carbon outputs associated with manufacturing EVs and producing the electricity that is required to charge them. Indeed, to the latter point, any benefit of having a population that takes their garages fully electric is completely contingent on countries’ abilities to transition their energy grids away from coal and towards sustainable sources. Fortunately, there is progress being made on that front; the BBC reports that “in 95% of the world, driving an electric car is better for the climate than a petrol car,” with the few exceptions being countries whose electricity grids still rely heavily on coal, such as Poland (4). Likewise, Figure 1 shows the Massachusetts and US national average emissions per vehicle for all-electric, hybrid, and gasoline-fueled cars. It supports the point that the vast majority of the time, charging and driving an electric car beats fueling and driving a gas one, at least in terms of emissions.
To the first point, the excessive mining of lithium is a major downside of EV manufacturing due to its effect on the water quality and supply of surrounding communities (8). Constantly improving battery technology, the adaptation of hydrogen fuel cells, solid state batteries, and other alternatives to lithium-ion, and the efforts of the private and public sector worldwide to commit to renewable energy deadlines will reduce and hopefully eliminate the burden that raw materials mining places on local communities (9)(10). If enough financial resources are dedicated to developing these battery technologies, which does not seem to be an issue at the moment, it is almost certain that EVs will keep getting cheaper, faster, and greener from here on. The focus should therefore be twofold: to push through implementation of personal vehicles powered by alternative sources while also prioritizing research on new battery technologies that will allow the production at scale of batteries that use less and less lithium. Of course, light vehicles and personal transport is one thing—decarbonizing the aviation and maritime sectors, the elephant in the room when it comes to supply chain carbon emissions, is a whole other subject.
The global aviation industry accounts for about 2% of all human-induced CO2 emissions, but the issue is that, unlike road-going vehicles, electricity in passenger aircraft is simply not feasible with today’s technology (5). It is worth noting that planes have come a very long way in terms of efficiency, with new models such as the Airbus A380 and Boeing 787 burning about the same amount of fuel per 100 passenger-kilometers as modern compact cars (5). The path towards decarbonizing aviation is, as Sustainable Aviation UK illustrates in figure 2, reliant not only on sustainable aviation fuels but also on a combination of improved engine technology, carbon capture and storage, market-based carbon offset schemes such as CORSIA, and smarter aviation practices aimed at burning less fuel in the first place (6). This projection also takes into account a 70% increase in passenger traffic by 2050.
Of course, this figure is one organization’s projection for one country. However, it does shed light on how aviation decarbonization could be scaled. Such efforts will need to be made in tandem with those made in the maritime industry, a sector notorious for using the dirtiest kinds of fuels; so while these emissions may only account for about 3% of all carbon emissions, these ships release 8% of all sulfur dioxide along with nitrogen oxide (7).
Apart from pushing electrification in personal vehicles, adopting a smarter aviation industry, and the transition away from fuel oils in the maritime sector, many decarbonization plans also stress the need for urban planning that promotes walking, biking, and as the previously mentioned UC Davis report terms it, “demand-responsive ride-hailing” (3). Indeed, this would naturally result in reduced demand for inner-city personal vehicle use, where increased traffic due to urbanization and population growth can result in vehicles performing below their average miles-per-gallon ratings. Less space used on roads also means more space used for residential, business, and recreational projects.
Simply manufacturing electric cars and trucks and creating new aircraft engines that use biofuels will not suffice. We need to recognize that the success of electric vehicles in eliminating carbon depends entirely on what is powering a country’s electric grid; that not just flying greener but flying smarter, with airports designed to reduce fuel burn on the tarmac, is necessary for making a dent in aviation emissions; and that urban planning—how we move about our cities, not just in what car—is crucial. Everything ultimately loops back to the idea of lifecycle emissions, meaning the producers and consumers of electricity and transport, as well as anyone in between who adds value, need to put their own effort into cutting carbon. As every living, breathing being on earth is a stakeholder in the journey towards net-zero emissions, it will require skin in the game from all parties. Some industries can get there faster than others, simply by the nature of the cost structure and alternative fuels available, but one cannot stress enough the importance for all leaders in transportation and urban planning to commit.