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Monday, April 26, 2010

The Ash Cloud: Not Good Enough

This is a longer version of a piece published on EDGE as special event on the Ash cloud. Do not quote without permission. Many thanks to Caterina Zaccaroni for the picture she took of the volcano in 2008

I’m not a scientist, I’m a philosopher, a social epistemologist, and I am definitely a European. While reading some of the scientific answers to John Brockman’s provocative question, I was wondering whether I could add some evidence not coming from the science of ices and fires, but from the more modest reality of European policy making.

You may be not aware of the inclusion in the Maastricht’s Treaty on European Union of the Precautionary Principle for potential ecological and health disasters: (Article III-233): “Union policy on the environment shall aim at a high level of protection taking into account the diversity of situations in the various regions of the Union. It shall be based on the precautionary principle and on the principles that preventive action should be taken”.

Roughly speaking, if you don’t know anything about the situation, be as prudent as you wish. This principle, that stems from the ecological Earth Summit in Rio in 1992, according to which: "In order to protect the environment, the precautionary approach shall be widely applied by States according to their capabilities. Where there are threats of serious or irreversible damage, lack of full scientific certainty shall not be used as a reason for postponing cost-effective measures to prevent environmental degradation" has been integrated not only in the ineffective Maastricht treaty, but also in many European laws, such as the French one (loi Barnier 1995: “The precautionary principle is a willingness to take action in advance of scientific proof [or] evidence of the need for the proposed action on the grounds that further delay will prove ultimately most costly to society and nature, and, in the longer term, selfish and unfair to future generations”).

Basically, in the old Schwarzenegger’s words: “First act, then think”… This riddle of decision making is made even more complex by the multilevel decision making in the European Union: After 5 days of uncertainty, ministers of transportation of European states, without any established decision making procedure, set up a conference call in which they decided against the IATA advice and following the Eurocontrol’s recommendations (Eurocontrol is a civil-military intergovernmental organization with 38 member states across the European Continent. The European Community is also a member) to close the European airspace. Note that this would have been impossible in the United States, where the precautionary principle is invoked only for military security reasons and where the Airline companies have the last word in safety matters.
When asked for justification of an apparent lack of proportionality between the potential threat of the ash cloud and the closing of the airspace (most evidence was based on computer simulations and on a Manual on Volcanic Ash released in 2007 by the International Civil Aviation Organization in which only two earlier cases of accidents due to volcano ashes in 1980 and 1982 were discussed), most European ministers didn’t find anything better than to appeal to the wisdom of proverbs: “We are never prudent enough in airspace security”. Well, “good-enough” wisdom is obviously not good- enough policy if it can ground a whole continent to earth just with a proverb.

We do not need better science in this case. What we need is better social science of how decisions are taken, how we can set up transparent and robust procedures and take evidence into account even in cases in which such evidence is underdetermined. When I was young and idealist, I heard social scientists talk about the duty of expert decisions to face the opinion of the society at large. Today we are confronted with an epistemocracy of the uncertain that makes people swallow the worst decisions under the authority of a so-called expertise. Definitely, not good enough.


Ross said...


You're right of course. But tell me, have you read Chris Hood's "The Government of Risk"? He studies regulation and identifies a number of different styles. Sometimes regulators leave it to scientists and engineers (as in much of nuclear safety); sometimes there's a political equilibrium between lobbies pushing and shoving (as with fishing quotas); and sometimes it's a matter of an emotional
fatwa (applying the precautionary principle to child safety, Y2K or

What may be interesting here is that we started out with fatwa (risk to passengers must be zero), and when reality hit us we moved to political equilibrium (2000 thingummies per whatsit). Perhaps if we get more volcanoes in the future it will move all the way to engineering; airliners will carry lidar to detect ash as they now carry stormscopes to detect lightning. And if the public were better
educated on risk, this move from fear to reason might go a bit faster. One of Chris's observations is that the evolution of bureaucracy is driven by blame avoidance. The more people criticise officials for acting irrationally, the more rational they may act.

Or am I being irrationally optimistic?

Ross Anderson

Anonymous said...

Des tests ont été faits au 3e jour de bloquage (vols d'avion à vide, mesure du volume de cendre par mètre cube). Certes, ça aurait pu être un peu plus rapide mais ça semble logique et ça n'a rien à voir avec le Traité de Maastricht. Comme quoi, il n'y a pas que les politiques qui écrivent n'importe quoi !

Anonymous said...

Slightly nit-picking but, there is unfortunately a very good reason why commercial airliners will never use lidar to avoid ash.

To do so would require frequent changes in altitude and direction. As the cloud is dynamic in local density and extent this would be unique for each plane.

A plane calculating it's own path (or deviations from it) would be a paradigm shift from the top-down approach used at present.

Given the extent of the ash and the localized information lidar provides it's also unclear how one plane could ensure they would not repeatedly fly up a safe channel which became blocked by high density ash causing them to turn back. Really you need lot of networked planes or other data to map out the cloud and safe paths.Unfortunately it's not obvious now how to implement this networked system.

Individual planes can't use lidar for avoidance at least with the current extent of ash and density of planes without a massive subsequent increase in collision risk.

Storm scopes are somewhat different. They are only used in the exceptional case that a plane has been badly directed through a severe storm. The plane can then take evasive action relaying this (+abuse) to the air traffic controllers. The controllers can then redirect future planes. Hence the path updates are announced and limited to one or two planes and local storms (the controllers will spot big ones).