In many regions around the world, climate change is exacerbating the frequency and severity of catastrophic weather events. The torrential rainfall and resulting extreme flash floods in parts of Germany and neighbouring countries in mid-July have once again inflamed the debate around the extent to which such occurrences can be attributed to climate change. Here are some insights from the latest research:

• Climate change adds energy to the atmosphere. More water evaporates from warmer oceans, and a warmer atmosphere can absorb more of that additional moisture. These two phenomena increase the likelihood of heavy precipitation, among other things.
• Many scientists believe that climate change is influencing weather hazards such as heatwaves, droughts, extreme precipitation, and storms in certain regions. However, it is not possible to definitively trace a specific weather event to climate change. All the same, modern research methods known as attribution studies enable scientists to determine whether a recent extreme weather event (e.g. heavy precipitation) in a specific region was made more probable by climate change.
• Other findings indicate that the above-average warming in the Arctic owing to climate change could, especially in the summer, weaken the jet stream and consequently slow the eastward movement of high-pressure and low-pressure systems. As a result, stationary weather patterns would occur more often.

• The low-pressure system Bernd was just such a stationary weather pattern. It essentially hovered above Central Europe for several days, causing strong storms and heavy precipitation in Switzerland, western Germany, Belgium, Luxembourg and the Netherlands from 12 July 2021. Western Germany was particularly hard hit, where the rainfall was so heavy in many places that it statistically occurs, according to historical meteorological data, less than once every 100 years. 
• Rapidly rising water, flash floods and mudflows then led to disastrous losses. Many buildings collapsed; vehicles and bridges were swept away. The water rose so quickly that many people died in western Germany. Soon thereafter, severe flash floods occurred in Austria and southeastern Germany. An accurate estimate of losses in the region is not yet possible.

"Our hearts are with the loved ones of the dead and the injured. We urgently need to invest more in protection measures – in Germany, in the rest of Europe and elsewhere – to prevent such awful consequences and losses from happening in the future. This is especially important in light of the fact that such disasters are occurring more frequently due to climate change. Better precautions make it more affordable to insure buildings, even in high-risk areas."

Torsten Jeworrek
Munich Re
Member of the Board of Management