Aviation stands at a critical crossroads in its journey towards a more sustainable future. Despite the industry's commitment to significantly reduce its planet-warming emissions by 2050, the path to achieving this goal remains unclear.
The primary challenge lies in the absence of straightforward methods to curtail these emissions effectively. While aviation contributes about 2.5% of global carbon emissions, its overall climate impact is considerably more significant.
This heightened impact is due to the emission of other greenhouse gases and heat-trapping condensation trails produced by jet engines. Complicating matters further, the demand for air travel is on an upward trajectory, with projections indicating a doubling of the global fleet of commercial airplanes by 2042, as reported by Boeing.
Gary Crichlow, the head of commercial analysts at AviationValues, sheds light on the issue: "By the most commonly used measure – carbon emissions – air travel’s problem is that it’s not only growing, but is also very difficult to decarbonize.
As other industries reduce their emissions faster, aviation is anticipated to be responsible for an increasing share of the budget." The core of the decarbonization challenge lies in the absence of a non-carbon energy source that can match the energy density of jet fuel in terms of scale, cost, safety, and reliability.
The Search for Sustainable Solutions
Medium- and long-haul flights are the biggest offenders, responsible for 73% of aviation’s carbon emissions. The Aviation Environment Federation, a UK nonprofit group, highlights the environmental cost of such flights.
For instance, a return flight from London to Bangkok can produce more emissions than the annual savings from adopting a vegan diet. As awareness of the climate crisis grows, travelers are increasingly opting for less damaging trips closer to home.
However, the question remains: when will a genuinely sustainable, "guilt-free" long-haul flight become a reality? The industry’s overarching goal is to achieve net zero by 2050, cutting as much of its planet-warming pollution as possible and removing any remaining emissions from the atmosphere.
Gökçin Çınar, a professor of aerospace engineering at the University of Michigan, outlines the technologies under consideration: sustainable aviation fuels (SAFs), electrification, and hydrogen. SAFs, which can be derived from various sources including algae, hydrogen, and captured CO2, show particular promise.
The most immediate potential lies in SAFs produced from waste materials, such as used cooking oils. "We can take that and through some chemical processes turn it into hydrocarbons," explains Çınar. "Jet fuel is also a hydrocarbon, and because of this similarity, we are able to use the SAF in the engines that we have today without modifying them."