How Do Planes Affect the Environment?

The airport closures during Iceland's recent volcano may have one positive effect: The cleared airspace may yield clues about how jet fuel burned at high altitude affects climate change. The no-fly week will add to data discovered during a similar period after the September 11, 2001 terrorist attacks on the U.S., when planes were grounded for three days. The sticky wicket in the case of the volcano-flight kibbosh is the ash in the air—scientists will have to distinguish the effect of the sun-blocking ash from whatever effect the absence of planes had. It is difficult to gauge the effects of jet fuel burned at high altitude, because there are so few plane-free days to use as points of comparison.