The climate debate is still in progress and a satisfying end in which all those involved reach out happily is far away. An excellent opportunity to add a little more fuel to the fire.
The very deliberately chosen title of this article may sound a little confusing at first. After all, as a veteran climate activist, one knows that the majority of scientists agree on the existence of anthropogenic climate change – even if there is uncertainty about the extent of its influence. Whereas the inclined climate sceptic tirelessly emphasizes that past predictions of doom were wrong with reliable regularity. No massive forest extinction, no islands disappearing by the dozen, and even the ozone hole seems to be closed again by about 2075.
According to this logic, it is only reasonable to be sceptical about the alarmism of Greta Thunberg and the movement Fridays for Future inspired by her. That’s not because the argument behind it is so powerful, but because we humans often don’t understand the world around us.
Evidence and Absence
The human mind has an inherent need to identify causal relationships everywhere in order to explain the world. We see the earth getting warmer and warmer since the Industrial Revolution, so it is quite clear that humankind is to blame. Or is climate only in a warm period again and the human influence is negligibly small, therefore continue as always?
None of these positions recognizes that it doesn’t really matter who is actually to blame, because any predictions based on the assumption of linear relationships are completely useless. However, before the climate skeptics triumphantly throw their arms into the air, a short detour into the philosophy of science and complex systems is necessary.
Such a system is characterized by the fact that it consists of innumerable components that may interact with each other. Among the properties of this interaction are non-linearity (B does not necessarily follow from A, proportionality is not given), adaptivity (the ability to react to changes), emergence ( new, higher-level properties that cannot be found in the individual components) and a few others that are not too important for basic understanding.
The Earth’s climate obviously belongs to the group of complex systems. However, this also poses the problem that the behaviour of such systems is impossible to predict accurately, since no model can include all components in its calculations. At this point the climate skeptic feels completely confirmed, because he always knew that one cannot trust these climate scientists and their forecasts. Without noticing it, however, he falls victim to one of the oldest problems of the search for truth: the problem of induction. As I wrote in a previous post, the idea is often attributed to the Scottish philosopher David Hume, who stated in A Treatise of Human Nature:
“There can be no demonstrative arguments to prove that those cases of which we have had no experience are similar to those of which we have had experience.”
In philosophy of science, this process is called induction. This means that, on the basis of certain premises, a possible general conclusion is derived. Note the use of the term “possible”, because the conclusion does not have to be logically compelling.
The consideration that no general laws can be derived on the basis of incomplete information is, however, already many centuries old. The Pyrrhonian skeptic Sextus Empiricus wrote about this already in the second century:
“If they intend to determine the general from the details by induction, they will do so by checking all or some of the details. But if they check some of them, the induction will be uncertain, since some of the details left out in the induction may violate the general; while if they are all to check, they will break the impossible, since the details are infinite and indeterminable.”
The most popular version of this problem is about the often mentioned black swan. If you go around the world and every swan you see is a white swan, it makes sense to conclude that all swans are white. However, a single black swan is enough to show that the general theory of white swans is not as universal as originally assumed. If these considerations are brought to a common conclusion, the following guiding principle emerges:
“The absence of evidence is not the same as evidence of absence.”
The failure of past predictions is not a reliable indicator that it must always remain so. In a complex environment, it is impossible to establish obvious causal relationships, but if more and more potential stressors are added, the risk of causing devastating events may increase.
It is dangerously naive to assume that there have always been different climate episodes in the past, and even if the situation worsens, humanity will be able to develop a new invention that prevents the worst from happening. In a complex world, it is by no means possible to make predictions based on past data. It is simply impossible to calculate rare events. A high risk aversion and thus the protection of the environment is the most rational decision. People tend to forget that in complex systems one plus one does not always equal two, but often much more. Stressors can act as super-additive functions and cause enormous damage.
Nobody knows what will happen, no model is able to predict the future.
The thing is: This is not necessary to realize that influencing systems you don’t understand can have unintended, negative consequences. By removing or at least slowing down some stressors, the risk of extreme events may be reduced. It does not require linear evidence or apocalyptic predictions to be aware of the potential damage that one’s actions could cause.
Protecting the environment is humane
Climate skeptics must be credited with the idea that correct predictions are in fact not among the things that one would cite as praiseworthy characteristics of human behaviour. However, to conclude from this that everything would somehow work out is not the answer to the problem. As climate change is a very abstract phenomenon for many people, it helps to transfer the argument just made to a more familiar event: the 2008 financial crisis.
The majority of economists did not see such a crash coming, let alone consider it possible. The mathematical models of economics at the time did not foresee such catastrophes, but of course it was by no means the first global economic crisis. It is in the nature of rare events that they cannot be predicted. The global economy is no less complex than Earth’s climate. Accordingly, forecasters also face the same problems here. Even then, there were a handful of skeptics who warned that the financial system could eventually face a huge collapse. They were right. Does this automatically mean that today’s climate skeptics are just as well on track? Perhaps. Perhaps not. Nobody knows. It would be desirable, but the risk that this is not the case can hardly be dismissed.
The public debate is facing a strange paradox:
Even if anthropogenic climate change does not exist (or does not exist to the extent to which it appears) and the world will be in perfect order as usual, where does the problem lie, at least in trying to live more sustainably? Even if one is not completely convinced of the apocalyptic narrative, there are undeniable environmental problems that adversely affect the quality of human life. The Earth itself will continue to persist. It simply exists. It does not care whether some intelligent monkeys inhabit it or not. The protection of our environment is not so much about the planet as it is about ourselves. It is something deeply humanistic.