A new study published in Nature has combined data on daily rainfall with subnational economy output from the last 40 years, showing that a region’s economic growth is hindered when there is an increase in wet days.
An increase in the number of wet days or extreme daily rainfall — leads to a reduction in economic growth, according to a new German study that also found wealthier countries are more sensitive to increases in rainy days.
Researchers modelled the impact of rainfall change on economic growth using historical data across 77 countries for the study.
“Changes in the Earth’s hydrological cycle are anticipated as a result of anthropogenic climate change,” the study found.
“Water availability affects agricultural productivity, labour outcomes and conflict, and flash flooding can cause damage and impact economic output.”
In Australia, the data showed that the whole of the east coast and the Northern Territory had historically shown the greatest drop in economic growth rates when the number of wet days was higher.
The research was published just a week after the Bureau of Meteorology (BOM) issued its annual climate statement for 2021, revealing last November was Australia’s wettest on record.
Lead author of the Nature paper, Leonie Wenz from the Potsdam Institute for Climate Impact Research (PIK) in Germany, said that economic growth slowed in places where the annual total of rain on days that exceed the 99.9th percentile of the distribution of daily rainfall between 1979–2019.
“Our previous understanding of the economic effects of rainfall changes [is] incomplete,” a statement from the researchers said, noting that more research was needed to quantify the impacts of future changes.
“Rainfall changes are difficult to model or are assessed on a single country basis, making it difficult to estimate the global economic cost of rainfall induced by climate change,” they added.
The study also suggested that droughts that differed from historical monthly means may also lead to economic losses.