It is hard to take precaution against events that are difficult or impossible to predict. That holds for all kinds of "systemic shocks" which include earthquakes, economic crises, climate-related events, and more.
Italy may be an especially vulnerable place for earthquakes. It is a country located in a highly seismic zone where a large number of buildings have been erected just by piling up bricks, without worrying too much about safety. The results can be seen in the earthquake of a few days ago and in several other earthquakes of the past decades. (see the image above, source). But, if Italy is a bad place in terms of precautions against seismic events, it is normal that everywhere large earthquakes strike, the damage is enormous. Even Japan, although a country that places a lot of attention on earthquake safety, was badly hit by the 2011 tsunami and by the 1995 earthquake near Kobe.
The discussion about the recent earthquake in Italy raised up some comments on my Italian blog, one of which I found especially silly. Summarizing it, it said, "If earthquakes cannot be predicted, how can you pretend to predict climate change? We should just wait and see."
I think that the logic of this comment doesn't need to be deconstructed but, at least it is further evidence that human beings are not rational creatures. Nevertheless, it raises an issue worth discussing about the predictability of climate change. Much of the debate on climate turns around the often raised objection against the need of doing something that says, "if you can't predict exactly what's going to happen, then we should just sit and watch". Obviously, nobody would even dream to raise such an objection against reinforcing buildings against earthquakes, although in practice the idea is often resisted. Nor, anyone would maintain that you shouldn't wear seat belts in your car because you can't predict exactly when an accident will occur.
So, why is the debate on climate change so special? In one sense, it is the sheer vastness of the problem. While you can always think that the next earthquake will strike somewhere else, there is no escape from climate change: it affects the whole planet and that surely makes people tend to react by disregarding even the most elementary rules of logic. In another sense, it I think that the problem is in the very concept of "predictions". Geologists know a lot about earthquakes. but they have wisely abstained from trying to make predictions about them. Climatologists, instead, have made a big effort to develop predictive tools and they keep publishing diagrams telling us what temperatures we should expect for 2050 or 2100. That has led to a heated debate about the validity of the models which, as all models, can only be approximated (the map is not the territory).
Don't make me say that there is anything wrong in climate models. They are sophisticated, physics-based tools, perfectly valid within the assumptions that they make. There is, however, a problem. Climate change and seismic phenomena are, at the most basic level, similar in the sense that they are both about the accumulation of energy in a reservoir. Geological faults cause the accumulation of elastic energy in the earth's crust. Greenhouse gases cause the accumulation of thermal energy in the atmosphere and in the oceans.
Now, it is known that the release of elastic energy in the crust is not a linear phenomenon and that, as a consequence, it generates sudden and catastrophic events. How about the release of thermal energy in the atmosphere/hydrosphere system? Mostly, we tend to think that it is a linear phenomenon: higher concentration of greenhouse gases in the atmosphere cause rising temperatures and, indirectly, rising sea levels. But, unfortunately, that's not the whole story and it cannot be.
Complex systems tend to react to forcings in strongly non-linear ways, something that I termed the "Seneca Effect". And the rising temperatures may create plenty of sudden catastrophes when linked with the other elements of the ecosphere and also of the human econosphere. Just think of the effect of a sudden increase in the sea levels on the world's economy, largely based on marine transportation. And think about the effects on agriculture: much of the recent turmoil in North Africa and the Middle East may be seen as a non-linear reaction to rising temperatures and droughts.
But the most worrisome sudden transition related to greenhouse warming is known as the "runaway greenhouse" or the "Venus catastrophe." It is the planetary equivalent of a major earthquake; something like what happened to the city of Amatrice, in Italy, completely razed down a few days ago. Of course, we may say that such a transition is "sudden" only in terms of a different time scale in comparison to earthquakes, but it may still be rapid enough to cause gigantic damage. We don't know for sure if such a catastrophe can occur on the Earth but, according to some recent studies, it seems to be possible. And make no mistake: a runaway greenhouse effect is not just a hotter earth, it involves the extinction of the biosphere.
In the end, the main problem of this whole story is that we don't know how to convince people about the risks related to non-linear phenomena, earthquakes, climate change and the like. Should we emphasize the risk? That has the unwanted effect that people tend to run away plugging their ears and singing "la-la-la." Or should we sweeten the pill and tell them that there is nothing to be really worried about; just a few minor adjustments and everything will be fine. That has the effect that nobody is doing anything, surely not enough. Will we ever find the right strategy?