The relationship between global climate change and the occurrence of floods is extremely complex and has so far been one of the least explored areas of climate change. For a long time it was unclear whether there was even a causal connection between global warming and floods. A recently published study now clearly shows the specific effects of global warming on the number and intensity of floods. In the international study, the data from over 3,700 water measuring points from the 50 measuring years in the period 1960 and 2010 were evaluated.
Climate researchers have long suspected that climate change has a significant impact on the amount of water in flood events. The reasons for this are the scientific facts that an atmosphere heated up by the general global warming can store more water and that sooner or later this water has to be given off again by rain.
The clear conclusion of the study is that the consequences of climate change in central and north-western Europe will increase large-scale river flooding in the future. The reasons for this are diverse. First, the weather models forecast increased rainfall in autumn and winter. Due to the climate change triggered by global warming, hot summers and periods of drought will increase throughout Central Europe and thus also in Germany. The heavy rains in the autumn and winter months thus hit the soil, in some cases very dry, which is no longer able to absorb the large masses of water. This can result in large-scale flooding.
Second, climate researchers predict increasing heavy rain in the coming decades, which can lead to flooding in many places. The reasons for this are the strong regulation of German rivers and the lack of natural overflows in many places. In densely populated areas in particular, the floods caused by heavy rain can cause considerable damage. River floods cause around $ 100 billion in damage around the world each year, and the number is rising. Flood management will have to adapt to these new realities in the years to come. Otherwise, it must be expected that the annual flood damage as a consequence of climate change will increase faster than in previous years.
Thirdly, climate researchers are also discovering changes in the atmospheric circulation as a result of climate change. One of the effects global warming appears to have on weather is the slowdown in the low pressure areas over northern and central Europe. As a result, these low pressure areas have more time to report their rainfall, which in turn increases the risk of flooding.
In addition to the increasing risk of river floods, coastal regions are also affected by increasing flood events. The background to this is the rising sea level around the world and the increased intensity of storms caused by climate change. According to a new calculation model, around 300 million people in coastal areas around the world will be affected by floods by 2050. This applies not only to very flat countries, mainly in Asia, but also to the entire German North Sea coast. Both the East Friesland region in Lower Saxony and the North Friesland region in Schleswig-Holstein must prepare for the increasing risk of flooding in the coming decades.