Figure 15.1 shows the main global emitters of carbon dioxide. Indeed, the airlines emit a surprisingly low 2%, but they are very visible and I think they can reduce their carbon dioxide output substantially further in the future.

About 15 000 aircraft service nearly 10 000 airports and operate over routes approximately 15 million km in total length. More the 2.2 billion passengers flew on the world’s airlines for vacation and business travel, and in excess of a third of the value of the world’s manufactured exports were transported by air. Further, as already mentioned, the aviation industry generates 32 million jobs worldwide and contributes nearly 8% to world gross domestic product. It goes without saying that air transportation has a big economic footprint. However, the aviation industry is not immune to the impact it has on climate change. As the aviation skies continue to crowd, so does the impact of carbon dioxide emissions.

Air travel is the world’s fastest growing source of greenhouse gases like carbon dioxide (http://www. scielo. cl/pdf/jotmi/v5n2/art06.pdf). Globally, the world’s commercial jet aircraft fleet generates more than 700 million tonnes of carbon dioxide in 2011.

Land use change & forestry 25% Building light and heat 20%

Industrial processes 3%

Other electricity and heat 12%

Other transport 2% Chemicals 6%

Air travel 2% Cement 5%

Road 13% Other industry 2%

Figure 15.1 Total global carbon dioxide emissions. Source: www. sascargo. com.

One person flying a return trip between Europe and New York generates between 1.5 and 2 tonnes of carbon dioxide. This is approximately the amount a European generates at home for heating and electricity in 1 year. Crowded skies translate to more flights, which equates to more consumption and waste. Con­suming more in the aviation industry equates to more greenhouse gas emissions, which negatively adds to global warming. Most experts believe that air travel could double within 15 years if current trends persist. By 2050, the IPCC believes that aircraft could account for up to 15% of the global warming impact from all human activities.

While much of the carbon dioxide is absorbed on Earth in plants and the ocean surface, a huge amount goes into the atmosphere, where it and other gases create a kind of lid around the globe — the so-called greenhouse effect. Heat that would normally escape into space is thus reflected back to Earth, raising global tem­peratures. Apart from engine efficiency and improvement of aircraft design, lighter composite materials, and better aerodynamics, finding an alternative fuel is part of the challenge for the aviation industry.

Like Boeing, Airbus has partnered with Honeywell Aerospace, International Aero Engines, and Jet Blue Airways in the pursuit of developing a sustainable second-generation biofuel for commercial jet use, with the hope of reducing the aviation industry’s environmental footprint. Alternative fuel research is a core tenet of the ecoefficiency initiatives of Airbus.

Aviation consumes approximately 240 million tonnes of kerosene a year. Replacing the current aviation fuel with biofuels from productive arable land that does not compete with food production would take almost 1.4 million km2, which is greater than twice the area of France. I do not think this is a good solution and a feedstock range of energy providers, such as waste, grass, woodchips, and algae, should complete the second-generation fuels, such as Pongamia, Crambe, Jatropha, and Camelina.

178 | 15 General Aviation and Biofuels

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