Scientists have been missing a critical factor when estimating the economic impact of climate change — rainy days — according to research published Wednesday in the journal Nature.
“More rainy days: that’s bad for the economy,” said Leonie Wenz, deputy head of the complexity science department at the Potsdam Institute for Climate Impact Research and one of the research authors. “Droughts and extreme rainfall events and the number of wet days … are all changing due to climate change.”
The survey of 1,554 regions in 77 countries found societies were ill-equipped to cope with unusual weather.
The effect of even slight changes was substantial. An increase in the number of wet days that would normally be expected during a six-year period could shave more than 1 percentage point off annual economic growth. More extreme storms and droughts also hurt.
In already wet places like Northern Europe, the impact of more umbrella days was smaller than in normally sunny countries where businesses were less adapted to working in the wet.
In places like Spain, unusually heavy rainfall can lead to serious disruptions that impact the economy. After a record-breaking summer heat wave, Madrid was battered in August by the second-worst summer storm of the past 100 years. The deluge paralyzed the city, flooding tunnels, interrupting metro and regional train services and clogging highways with traffic jams caused by weather-related accidents.
The effect of additional rain isn’t always as dramatic, but the cumulative effect of more frequent and intense downpours can delay workers, interrupt supply chains and cause minor damage from small-scale floods or falling tree branches, which can have a significant economic impact.
“In general, everything that’s a deviation from what we’re used to can be bad,” Wenz said.
“These costs haven’t been accounted for so far in estimates of the costs of climate change,” said Manuel Linsenmeier, a researcher at the London School of Economics who was not involved in the study.
Rich countries were harder hit, with their larger service and manufacturing sectors more vulnerable to increased rain than developing countries, where agriculture is typically a larger share of the economy, scientists found.
This is “bad news,” Linsenmeier said, because “the extent to which economic development can be used to buffer against rainfall shocks under future climate change appears limited.”
The problem is expected to grow as climate change disrupts rainfall patterns.
“If we don’t stabilize the climate, this will be so much more costly,” Wenz said.
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