Today, commercial flying is exceptionally common. Combining domestic and international trips, a projected 40.1 million flights will be performed in 2024, and those numbers are continually going up as countries such as China and India develop economically.
The two aforementioned countries experience a 10 percent increase in passenger demand for flights per year, according to the Guardian.
Globally, passenger demand for international and domestic flights increases by roughly 5 percent annually. Unsurprisingly, the continued expansion of the commercial aviation industry comes at a significant environmental cost. Flying is already responsible for 3 to 4 percent of total C02 emissions, or about 1.3 billion tonnes annually. While a 3 to 4 percent share is bad enough, the percentage of overall C02 emissions from aviation keeps increasing yearly. Due to its expanding size and passenger demand, emissions from aviation go up disproportionately compared to other industries, with some estimates suggesting a threefold increase in C02 by 2050.
Due to these emission-related shortcomings, a central question must be asked: can we mitigate aviation’s environmental harms and successfully curb emissions while not inhibiting its growth?
Well, most technological solutions are targeted at improving the environmental impact of a plane’s fuel. Most airplanes use kerosene, an easily combustible hydrocarbon that releases very high amounts of carbon dioxide, carbon monoxide, nitrogen dioxide, and nitric oxide - which are all toxic greenhouse gasses that contribute significantly to climate change.
Several alternative fuels have been proposed and tested over the last few decades. One alternative, biofuels, are derived from cooking oils and refined into working jet fuel at special plants.
While they are environmentally preferable to conventional fuels, biofuels still emit 50 to 70 percent of what traditional fuel sources do.
Additionally, biofuels are significantly more expensive to produce than conventional sources. Most estimates state biofuels cost roughly 50 percent more to produce.
These technical and financial issues, coupled with the fact that major airlines are taking limited steps to increase their use of these renewable fuels, make biofuels’ future viability unlikely.
Indeed, market trends and predictions from analysts mirror this reality, with the New York Times reporting that, “Rystad Energy, a Norwegian consulting firm, predicts that renewable fuels will become increasingly economical after 2030 and supply 30 percent of all aviation fuel by 2050. But IHS Markit, a U.S. consulting firm, estimates that sustainable jet fuel will make up only 15 percent of all jet fuel by 2050.” Even if the former, more optimistic prediction comes true and biofuels make up 30 percent of aviation fuel by 2050, that would not generate a noticeable difference in emissions.
Another proposed alternative is a hydrogen fuel model. Theoretically, hydrogen gas, which we have a virtually unlimited supply of in the atmosphere, can be used as jet fuel.
Unfortunately, no hydrogen gas-powered airplane has been created yet, and research teams working on such a model admit that it will take decades for this technology to even be a serious consideration.
While hydrogen may be a worthwhile long-term project, it certainly should not be the solution we move towards in the status quo. Climate change is an ever-advancing threat that cannot be addressed with theoretical technology that will only be a potential option in thirty years.
Finally, there is the fully electric model that proposes large batteries store the energy necessary for airplanes to function.
This concept has worked in very small planes that do not–-not even proportionally to larger planes–-require much energy to complete flights.
However, the electrification of larger commercial aircraft is virtually impossible with our current technology. The size and energy-carrying capacity needed of a battery to power a jumbo jet would be astronomical.
Similarly to hydrogen fuel, we shouldn’t rely on questionably feasible, long-term solutions to combat the current issue of climate change and human-caused environmental disasters.
The common denominator of these solutions' shortcomings is airlines' inability to decarbonize. Despite the increasingly severe environmental impact of aviation, the vast majority of airlines continue to use conventional fuels and have implemented lackluster steps to reduce emissions in the last couple of decades.
Notably, carbon sequestration (a process where C02 is removed from the atmosphere and stored in a concentrated pool, usually in the soil) has recently been held up by several major airlines as an effective counterbalance to their massive emissions. Despite airlines’ claims, carbon sequestration is not an effective nor commonly used way to reduce carbon emissions according to Researchers for the Institute for Energy Economics and Financial Analysis.
At worst, the technology is simply a waste of money that allows corporations to distract from where the emissions are coming from: their misbehavior and refusal to change. Tellingly, emissions from the aviation sector continue to climb steadily despite years of promises and anemic initiatives to reduce environmental damage.
Other issues are also associated with commercial flying as a means of transportation. Flights are often uncomfortable, unreliable, excessively long due to frequent cancellations and delays, and contribute to noise pollution in communities that live in proximity to airports.
When all of these issues are considered in tandem, the future viability and sustainability of aviation ought to be reasonably questioned. Perhaps, an entirely different means of transportation can and should replace the bulk of flights.
Of course, international flights covering thousands of miles of distance will always be necessary, but they do not represent the vast majority of flights. According to the Bureau of Transportation Statistics, domestic travel accounted for 88 percent of all flights in the United States in 2019. So, attempts to shift away from aviation could seriously reduce carbon emissions since you would only have to replace domestic, relatively short-haul flights to see a tangible effect.
Trains–-specifically high-speed rail infrastructure–-can be an adequate replacement for most domestic flights.
Modern and fast train networks are, for one, significantly more convenient. A lengthy and stressful wait at the airport with frequent cancellations and delays would be erased if they were replaced with an expansive network of high-speed rail-powered trains. Under this model, waits would be cut down substantially, and the hassle of TSA and security avoided.
The conditions on modern trains are also typically more comfortable, with more room being present for passengers to rest, move around, or sleep.
Although planes technically move at a higher speed than even the fastest high-speed rail trains, reduced wait times and inconveniences for train stations versus airports may make train routes faster than some domestic flights.
In addition to these convenience and comfort-related benefits, high-speed trains are vastly better for the environment. Per passenger, general rail emissions are only 20 percent of what air travel is responsible for, with modern, electrified networks contributing even less.
Therefore, the widespread implementation of high-speed trains as a replacement for most domestic, short-haul flights will be able to halt the endlessly increasing emissions of the aviation industry, in line with being more comfortable and convenient.
Despite rail’s clear superiority, there will still be challenges. At present, America has almost no high-speed rail, and its current passenger lines are outdated, slow, and inefficient. Building a high-quality, modern high-speed rail network that spans across the contiguous US will cost hundreds of billions if not trillions of dollars. Furthermore, construction will likely take several years, potentially stalling as numerous engineering issues arise.
With an ambitious enough government program, however, a deliberate and calculated switch from predominantly domestic flights to train use is possible and is orders of magnitude more pragmatic than any of the other, fuel-targeted attempts to curb aviation’s emission problem.
Such a switch is not unprecedented either. In May of last year, the French government banned several domestic flight routes and incentivized their citizens to use its comprehensive rail network to travel between cities instead.
In the somewhat longer term, once an expansive high-speed rail network has been established, a similar policy could be pursued in the US. Perhaps banning certain flight routes is overly harsh, but reducing tax breaks and subsidization for airlines that keep tickets artificially low can provide a necessary incentive to facilitate a move to trains.
Ultimately, to avoid environmental disasters from the accelerating emissions from aviation, we must invest in high-speed rail infrastructure and trains, simultaneously boosting passenger’s comfort and convenience with the new system.