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Flooded region in Rhineland-Palatinate
Photo: Thomas Frey / picture alliance / dpa
Extreme weather events will increase in the course of global warming - climate researchers have long been certain of this.
The concrete impact this can have was most likely shown by the flood disaster in parts of southern Germany in the summer.
A simulation by the Potsdam Institute for Climate Impact Research (PIK) is now looking into the consequences of such floods or other extreme weather events on the economy. Accordingly, in a factory, for example, there would not only be production losses on site. The disaster could weaken the entire supply chain and lead to a kind of global "shock amplification". What the researchers mean by this: If extreme weather events occur at about the same time, they can overlap and even rock each other. This carries the risk that the economic effects of the increasing extreme weather caused by global greenhouse gas emissions could become greater than previously assumed.
"What we call economic wave resonance could be decisive in the future when assessing the economic impact of the climate," explained PIK researcher and study author Kilian Kuhla. Basically, it is true that the effects of extreme weather lead to losses in regions in which there are then shortages in supply - and at the same time to profits in other parts of the world, which then experience increased demand and thus higher prices.
"But when different weather extremes overlap, the economic losses in the entire networked global economy are on average 20 percent higher than the losses caused by the individual events combined," explained Kuhla.
"That's what our simulations of river floods, heat waves, and tropical cyclones show - and that's pretty worrying."
For their study, the researchers modeled the reaction of the networked world economy and calculated 1.8 million economic relationships between more than 7,000 regional economic sectors.
Most economically relevant countries are therefore affected by the wave resonance effect. Due to its outstanding position in the world economy, China in particular has an above-average effect of more than 27 percent additional losses if extreme events overlap than if they occurred independently of one another.
"When two separate events send shock waves through the global economy, they pile up like a tidal wave," said climate researcher Anders Levermann.
This therefore applies not only to simultaneous, but also to successive disasters when the economic effects of the various disasters overlap.
"If we don't reduce greenhouse gases quickly, it will cost us dearly - even more than we previously expected," explained Levermann.
joe / AFP