There has been much discussion in recent years about reducing the consumption of energy and production of greenhouse gasses in the transportation space. Cars have gone from gasoline to diesel to hybrid to fully electric. Ridesharing has transitioned from something aimed at reducing congestion on roads to one which hopes to limit the amount of greenhouse-gas emitting cars on the road. Given the number of cars on the road, it is easy to see why two of 15 ‘stabilization wedges’ proposed by Pacala and Socolow focus on automotive transportation .
Though automotive transportation might be the most easily addressed sustainability issue in transportation, climate change is sure to affect many other sectors across the transportation space, such as in air travel. Unlike cars, commercial aircraft cannot yet be powered by electric energy, and rely on petroleum-based fuel for power. The Intergovernmental Panel on Climate Change estimated that in 1992 aircraft were responsible for 2% of all human-based carbon emissions and 13% of transportation-based emissions . Miles travelled by aircraft has increased from 8.6% of all domestic travel to 12% in 2014, and emissions have increased accordingly . Aircraft are roughly half as efficient as automobiles on a per-seat basis, so as it gains share of total transportation it is becoming increasingly important to focus on . Air transportation may not yet be large enough to justify its own stabilization wedge, but it is undoubtedly an area where improved efficiencies can lead to significant reductions in overall greenhouse gas emissions.
Given that there were over 600 billion passenger-miles flown on US domestic flights in 2014, it is no surprise that airlines are trying to reduce fuel costs and emissions . As such, aircraft manufacturers such as Boeing are attempting to increase the fuel efficiency of their aircraft. To that end, a recent meeting of the International Civil Aviation Organization (ICAO) in Montreal led to the adoption of new regulations on emissions by over 190 countries. In this agreement airlines must purchase credits to offset their emissions from commercial flights . Though there is much to be done before any true benefits are realized, this demonstrates the changes coming about in the aviation sector.
Boeing has taken these measures very seriously and has considered the fuel economy of its commercial aircraft to be a crucial differentiator for some time now. Boeing has begun to manufacture aircraft fuselages out of composite materials which are lighter and more fuel efficient. Individual aircrafts can see up to a 20% improvement in fuel efficiency and switching entire fleets to composites from legacy materials can improve overall efficiency by 14-15%  Boeing’s 777X, to be introduced in 2020, will have the world’s largest composite wings, and the 787 Dreamliner will reduce carbon emissions by 20-25% compared to the aircraft it will replace. Improvements to engine efficiency and aircraft design will contribute to further gains .
Boeing first formally set operationally focused environmental goals in 2007, and is currently working towards its second set. Boeing has undertaken measures to reduce consumption in its own offices, pushing company-wide recycling initiatives, reducing water intake and energy consumption, and promoting zero-waste-to-landfill facilities . Efficiency gains have also been achieved in supply chain management and manufacturing. Since 2012, Boeing has reduced hazardous waste production by 11.2%, greenhouse gas emissions by 8%, solid waste by 6.9% and water intake by 10.3%. 
As Boeing looks to the future, it is making many of the right moves. The company is examining biofuels for jet propulsion, pushing towards zero-emissions facilities, and donating time and money to conservation efforts . Moving forward, Boeing must continue to work with its suppliers and partners to explore additional ways to reduce energy consumption and greenhouse gas emissions both within its own operations as well as by the aircraft the firm produces.
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