Now that the leader boards in European airports are again listing flights that are on time, and stranded travelers are finding their way, perhaps we might pause to say thanks to the volcano that blew its stack in Iceland.
When Eyjafjallajokull erupted on April 14, the diminutive but destructive Icelandic corker did us an unheralded favor. Believe it or not, all that ash swirling into the upper atmosphere was actually a minor boon to the war on global warming. About 11,000 European and international flights a day were canceled, and grounded aircraft don't pollute. With air travel over much of the continent slashed by 60%, CO2 emissions from aviation fell by about 200,000 tons a day, according to data from the independent British research group RDC Aviation. Since the volcano is estimated to be issuing 150,000 tons of CO2 daily, Europe temporarily lowered its carbon footprint by about 50,000 tons a day.
The reduction is a mere hiccup, of course. The savings is a little more than Luxembourg's and a little bit less than Estonia's daily output of heat-trapping gases. In the course of a year, the change will be almost imperceptible since, as the United Nations reports, humans produce about 73 million metric tons of carbon a day. With aviation emissions estimated at about 2% of the worldwide total, unless Eyjafjallajokull does what it did the last time it erupted — belching the Earth's gaseous juices for more than a year, from December 1821 to January 1823 — then the halt won't amount to much.
But what the present storm cloud over Europe demonstrates is our growing dependence on a form of travel that, if unchecked, will swamp many of the reductions made elsewhere in the battle to combat global warming. The fact is, despite the falloff in passengers after 9/11, airplanes are the fastest-growing source of man-made greenhouse gases, according to a 2006 report by the European Federation for Transport and Environment.
While aircraft fuel efficiency is predicted to improve by 1% to 2% a year, annual air traffic is predicted to climb by 5% every year, pushing CO2 emissions up. Cars still cough out far more greenhouse gases than aircraft, but according to the Aviation Environment Federation in Britain, flight emissions are growing six times as fast as tailpipe emissions.
What's more, burning jet fuel at altitude has double the damaging effect. The AEF estimates that if the current growth rates in air travel continue, when added to the greater harm CO2 does in the clouds, "aviation's impacts will exceed road traffic's in under 20 years."
There are not many ways, at least in the near term, that airplanes can become more fuel efficient or that high-octane kerosene can be replaced by more environmentally friendly fuels. For example, one alternative fuel, biobutanol, which can be processed from sugar beets or straw or soybeans, would require farmland the size of Florida to produce just 15% of the industry's needs.
The most efficient way to slash these carbon emissions is to build high-speed electric trains, because they emit anywhere between a tenth and a quarter of aircraft greenhouse gases. We all know how feeble passenger trains are in the United States, and the climate change bill now wallowing in the Senate will do little to lay bullet train tracks, let alone mandate airlines to dramatically conserve.
So perhaps our hope for the near term should be that Katla, one of Iceland's "Angry Sisters," will blow its restless top. If that happens, perhaps airports as far away as Los Angeles will have leader boards flashing "Delayed" for every flight.
Greg Goldin is an environmental writer and the architecture critic at Los Angeles Magazine.