Is climate change already happening?

by Mojib Latif

Earth, how are you doing? (Issue I/2018)


Where the media are concerned, climate change gets interesting when it is dramatic. When devastating weather events take human lives, camera crews and reporters flock to disaster sites. When catastrophic storms strike, the “extreme weather” is quick to hit the headlines, as happened with last year’s hurricanes across the Caribbean and the United States. In response, reporters are always quick to pose the question: Was the disaster due to a climatic or weather phenomenon?

From a meteorological point of view, this question cannot be easily answered - and that may come as a surprise. Take throwing a dice as an example. Each number has the same probability of being rolled. If we tinker with the dice to make a six more likely to be rolled than other numbers, we will roll more sixes, but we cannot say for sure in every single case whether the manipulation of the cube led to the throw of the six. It could have just been luck.

In this analogy, a single six is a completely normal weather extreme and nothing out of the ordinary. The accumulation of sixes, however, could be related to our manipulation of the system, for example, our influencing climate change and the earth's atmosphere. In order to figure out how many sixes were due to our manipulation — how much climate change is already influencing the weather — you would need to throw dice repeatedly, or, in the case of climate change, take accurate measurements for many decades.

But it is clear that climate change acts as a catalyst for extreme weather events. Here its influence can best be explained with hurricanes. They arise over marine areas where the water temperature is at least 26.5 degrees Celsius. At such high temperatures, the water evaporates particularly fast. That means, the warmer it gets, the more “fuel” is available to power the monster storms.

Nevertheless, it would be wrong to claim that the number of catastrophic weather events would increase with absolute certainty as a result of climate change. The climate is far too complex a system for such chains of cause and effect to be established. After all, some of the effects of climate change will serve to weaken other effects. During the El Niños, unusual, non-cyclical currents in the oceanographic-meteorological system, the tropical Pacific warms up by several degrees every few years, suggesting that hurricanes would occur more frequently during the storms.

But in fact the opposite is the case. During the El Niños, it is not just the water temperature in the Pacific that is changing. Simultaneously, over the ocean microbursts, or small but forceful downward drafts, become stronger. These actually hinder the development of hurricanes according to recent studies.

But does this ambiguity and complexity matter so much? The pragmatic answer is no. Contrary to the media reports, it is not extreme climatic changes that should worry us, but rather the unspectacular day-to-day changes which are already in full swing. While we debate whether extreme weather events such as hurricanes and cyclones will increase, individual ecosystems are already reeling from the creeping impact of climate change. Phenomena such as desertification, the melting of glaciers and the rise of the oceans already make many places in the world uninhabitable. In the future, such events will clout us far harder than the next hurricane.



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