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The news on Sunday was full of references to Virgin Atlantic's first biofuel-powered flight from Heathrow to Amsterdam. The fuel combined 20% biofuel, which powered one engine, and 80% traditional jet fuel, which powered the Boeing 747's other three engines. The biofuel for this flight was a mixture of coconut palm and Brazilian babassu nut oil.
Richard Branson, the flamboyant president of Virgin Atlantic, presents the flight as the first step towards environmentally friendly air travel. As he says in the article linked above: "This pioneering flight will enable those of us who are serious about reducing our carbon emissions to go on developing the fuels of the future." However, there is reason to be skeptical of this sort of flight as a solution to the emissions problems associated with air travel.
First, there are problems inherent to biofuel. For some time now there has been evidence that the most common types of biofuel currently in use - ethanol and biodiesel - are net energy losers. Presumably the production process could be made more efficient in the future, but both have a long way to go before they can become sustainable from an energy perspective.
Even without the energy loss, it would take a massive amount of agricultural land to produce sufficient biofuel to replace current petroleum use. To get that land, one could either convert current agricultural land to biofuel production rather than food production, or convert other types of land into agricultural land. Taking land away from food production would result in higher prices for corn and other grains, and higher prices for food overall. Since we all need to eat, and since conversion of suburban subdivisions into cornfields is unlikely, the most likely source of production would be "unused" land - basically the forests, fields, and marshes that have not yet been paved over.
The biggest areas of agricultural expansion have been in the tropics, especially southeast Asia, Kenya, and Brazil. Tropical rainforest is being cleared for biofuel production or for other economic purposes displaced by biofuel production. A recent study concluded that conversion of native ecosystems into cropland causes more greenhouse gas emissions than are saved by the use of biofuel over petroleum. Clearing tropical rainforests exacerbates the problem, since rainforests act as a global carbon sink. Deforestation in the tropics also brings terrible results for biodiversity. The Virgin Atlantic flight used fuels derived from tropical plants, including over 150,000 coconuts.
All of these problems have led me to believe that biofuels are not sustainable as energy sources. I would be glad to change my mind if evidence were presented to the contrary, but I am afraid that the current options are not a solution to climate change.
Second, air travel would be wasteful even if biofuel could be made environmentally friendly. Powered flight requires significantly greater amounts of fuel than automobile or rail travel, and emits significantly greater amounts of pollution. While we may eventually have more efficient aircraft, we should not expect significant improvement compared to other transportation modes.
This is not to say that no one should fly, or that research into alternative fuels should cease. Research should certainly continue into any promising alternatives. As for air travel, in some cases it is the easiest way to get from one location to another, and for now it is hard to see a suitable alternative.
In the long term, the best way to reduce the environmental impact of air travel is the development of high speed rail networks for short and medium distance trips, so that airlines are reserved for long-range travel. Of course, corporations like Virgin Atlantic would not favor diverting their customers to other transportation modes, but serious reformers should not be swayed by such parochial interests.
