HS Environment Rainy days chastise the economy – Scientists calculate the impact of extreme weather events on economic growth

When as the number of rainy days increases, the economy suffers. Rich countries, and especially their industrial and service sectors, are being hit hardest by the increase in rainy days and extreme rainfall.

This is what a recent issue of the prestigious Nature Journal says research. It calculates how changes in rainfall due to climate change will affect economic growth.

If looking at the annual rainfall, it is observed that an increase in rainfall will generally benefit economies – and in particular those that are dependent on agriculture.

However, it is also important how the rain is distributed over the different days of the year, emphasizes recent research Leonie Wenz.

“Increased daily rainfall is proving to be detrimental, especially to rich industrialized countries such as the United States, Japan and Germany,” says Wenz of the German Potsdam Institute for Climate Change. in the bulletin. He himself works at the institute.

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“When we destabilize our climate, we are damaging our economies.”

“Looking at short time periods instead of annual averages helps to understand what’s happening: it’s the daily rainfall that poses a threat,” adds the professor, who is also part of the research team. Anders Levermann From the University of Potsdam and the Potsdam Institute.

“Climate shocks brought by the extremes of the weather threaten our way of life rather than gradual changes. When we destabilize our climate, we are damaging our economies. ”

Researchers looking at more than 1,500 regions from 77 countries around the world. More than 30,000 observations were made over a 40-year period, from 1979 to 2019.

The group combined the data with the total production of these areas. In addition, they calculated how rainfall affected agriculture, industry and services.

Thus, higher annual rainfall generally benefits economic growth, but when it rains very heavily each year, the benefits clearly diminish, the analysis shows.

The researchers also looked at the variation in rainfall on a monthly basis. The exceptionally dry months caused significant financial losses. The months, which stood out from the historical averages as particularly rainy, were less severe for the economy.

“This suggests that economies are adjusting to prevailing rainfall over monthly periods,” the researchers write.

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“We are already seeing the impact of climate change most clearly at the extremes of rainfall.”

Previously it has not been reported that the effects of individual extreme rainy days on total production have not been studied.

First, the increase in the number of days counted as rainy days was reflected in a slowdown in economic growth. Second, extremely high daily rainfall discouraged the productive capacity of the economy.

The effects of both of these metrics were most pronounced in winter and fall, not so much in summer and spring.

According to the results, the richest economies are most affected by the increase in the number of rainy days and the increase in the extremely heavy daily rainfall.

Conclusionthat it is the rich economies that are hit harder than the poorer ones, refutes previous assessments, says the results Xin-Zhong Liang from the University of Maryland, USA. He did not participate in the study.

“The prevailing hypothesis is that in large developed economies with well-funded resources for recovery, the impact of natural disasters (including increases in rainy days and extreme rainfall) should be small, and sometimes even positive,” Liang write In a recent issue of Nature.

Moreover, the finding that extremely heavy rainfall would not so much shake agricultural production but industry and services contradicts the prevailing view.

In the past, for example calculatedthat extreme rainfall could tax corn crops in the United States by as much as 34 percent. In this way, heavy rains can cause damage comparable to extreme drought.

Climate change has slowed global agricultural productivity by about 21 percent in the last 60 years, says research, published last year in the journal Nature Climate Change.

Extremely heavy rains have plagued the earth in recent decades, both more frequently and more strongly. This trend will continue as climate change progresses, estimates the International Panel on Climate Change in its IPCC report last year.

As the climate warms, warm air is able to absorb more moisture. It eventually ends up in the ground as rain, and it is the heavy rains that increase.

“We are already seeing the impact of climate change most clearly at the extremes of rainfall,” the first author of a recent study Maximiliam Kotz says in a press release from the Potsdam Institute.

Extremely heavy rainfall may also be associated with heat waves, sudden cold spells, droughts, storms and other extreme events, Liang writes in Nature. They can also affect production capacity in other countries, as economies are interdependent in a globalized world.

More research is needed into the mechanisms, Liang says. He says the majority of climate models looking to the future underestimate how much extreme rain is coming. Thus, there are also many uncertainties associated with calculations of the economic impact of climate change.