The ongoing closure of European airspace due to volcanic ash after the Eyjafjallajökull eruption may already have claimed the lives of dozens of travelers without a single plane being crashed. The problem is that travelers are forced to seek alternative transportation, which typically are less safe than flying.
At first sight the situation looks clear: closing airspace will save lives as there will be no risk of planes crashing because of clogged engines. However, the situation is much more complicated than that. As flying by plane is one of the safest forms of transportation, closure of airspace endangers travelers' lives as they have to use more risky alternatives. This is mostly overlooked as people tend to be more afraid of plane crashes than of dying in a car accident. After 9/11 almost as many people have died by the increased use of cars in fear of plane crashes as in the terrorist attacks themselves. As Nassim Nicholas Taleb calls it, this is "focusing on the specific when you should focus on the generalities".
Now let us find an estimate for the number of people that have already lost their lives due to this. Of course, that is quite difficult to calculate, but we can make some reasonable assumptions. First, German rail operators have reported that there have been 30% more passengers using long-distance trains in recent days. Let us assume that the rest of Europe has similar numbers. According to EU mobility statistics people go by car three times more kilometers than by train. Now of course for longer distance travel this will probably look different, so lets assume that people are as likely to switch to cars as to trains. Then, this 30% increase in train passengers leads to a 10% increase in drivers on the roads. According to the same report, there are about 40,000 deaths from car accidents a year in the EU, meaning that each day 100 people die on the streets. True, not all of EU airspace is closed, but there are also non-EU countries affected. You might also argue that these additional travelers mostly use motorways, which tends to be safer by a factor two to four; however, this is probably compensated by the fact that travelers now having to take the road are more fatigue due to the length of the trip. Now a 10% in traffic translates into approximately 10 additional deaths in car accidents, meaning that we can expect that dozens of people already have died as a consequence of the closed airspace.
Of course, the real threat of volcanic ash to air safety is difficult to assess quantitatively, leaving you with little to compare with. However, stating that closing airspace is a no-brainer if you are concerned about transportation safety is simply wrong. And in any thorough risk assessment regulators must also weigh the risks of using more dangerous alternatives than airline travel, meaning that such large-scale bans have to be considered with great care.
Copyright 2006--2011 Hendrik Weimer. This document is available under the terms of the GNU Free Documentation License. See the licensing terms for further details.