The revelation that the decision to close Europe’s skies following last week’s eruption of an unpronounceable Icelandic volcano, and the spewing of ash into the sky, was triggered by advice from the Volcanic Ash Advisory Centre of the UK Met Office, based not on all relevant empirical evidence but on their computer model, has led to no small controversy... the Met Office spokesman claimed that this was irrelevant, since the policy in force was one of 'zero tolerance'. This, of course, is complete idiocy (and is conspicuously not the policy in the US, whose air safety record is as good as Europe's). It is, however, the so-called precautionary principle again – and indeed only a few days ago the Eurocontrol spokeswoman was explicitly justifying the original blanket flying ban on the grounds of the precautionary principle.
As we have stated multiple times before, computer models are worthless when used as a basis for making major policy decisions, including those regarding climate change. Unless the computer "prediction" is based on hard physics and well-established, scientifically known relationships, the computer models can end up being more dangerous for society than the theoretical calamity they are predicting. This is especially true when the models are used in combination with the infamous total-risk-avoidance precautionary principle to justify imposing major decisions and regulatory actions.
The recent Iceland volcano eruption and the subsequent closing of European airspace for an extended period is just the most recent massive computer model failure and clear evidence of the harm these models do. In a nutshell, the computer model prediction of Iceland volcano ash and its atmospheric spread was used by government policy makers to close major portions of EU airspace to aircraft for multiple days. This major decision was not based on scientific evidence nor actual observations.
As real-world data poured in though, the volcanic ash cloud actually was not a threat to European aircraft, but the tremendous economic damage and disruption imposed by the toxic combination of the the precautionary principle and the computer models had already been done. The end result is a human manufactured disaster, based on computer junk output, that is facilitated by alarmist scientists and politicians, who are incapable of moderating their hysteria that is so publicly infectious, and that is sooo coveted by the mainstream press.