Is Jet Fuel Next?

Over the weekend I had a chance to catch up on some of the articles that have languished during my recent relocation. It'll be a while before I feel fully caught up on events in the industry and the world, but at least I feel less out of the loop. One of the articles that caught my attention was this excellent report in the Economist on the environmental issues facing global aviation, particularly the growing focus on fuel consumption and greenhouse gas emissions from this sector. The article includes some interesting comparisons of the emissions from air travel relative to other modes, a topic that's come up in this blog from time to time. Their conclusion mirrors what I've said for years: aviation has gotten a relatively easy ride on the environment, but that won't last forever.

Air travel has been a great boon to mankind and is probably the signature innovation of the last century. But as it expands, so does its environmental impact, particularly when it is adding net new travel over long distances, rather than displacing existing travel via road or rail. The Economist cites EPA figures indicating that aircraft account for only about 3% of all greenhouse gas emissions, which is consistent with its roughly 4% share of total energy consumption, based on a share of just under 10% of total petroleum usage. But that modest share will rise, as air travel expansion outpaces other forms of energy consumption. It's startling to read that the growth in aviation emissions might offset more than a quarter of the EU's other emissions reductions by 2012, the end of the first Kyoto compliance period.

And while the Economist looks mainly at the impact on climate change, that's not the only issue the industry--both commercial aviation and its fuel suppliers--must worry about. For example, jet fuel has escaped most of the anti-pollution scrutiny and reformulation of the last couple decades. At 0.3% (3000 parts per million) its sulfur content, which was once comparable to that of diesel fuel, is 200 times higher than the ultra-low-sulfur diesel specification that has just gone into force in the US. While most of the sulfate emissions associated with burning jet fuel occur outside of urban pollution-control areas, they have long been thought to influence such climate-related issues as cloud formation. Oxides of nitrogen are even harder to avoid, given the high combustion temperatures in turbine engines.

I don't see any easy solutions. As the article points out, air travel is tightly linked with economic growth, and there's no handy alternative to kerosene-based jet fuel, unless it's the synthetic distillate from coal- or gas-to-liquids processes. These will have similar or even greater environmental implications, at least in terms of greenhouse gas emissions. At the same time, it's hard to imagine that air travel will get another "bye" in future climate change negotiations, as it did in the Kyoto Treaty. Stay tuned.