Anyone who thought Germany was well-prepared enough to cope with the effects of climate change was in for a rude awakening this summer. As a low pressure system dubbed “Alfred” battered the country this week, massive amounts of water flooded the market square in the picturesque town of Goslar on Wednesday, and in nearby areas there was almost a meter of flooding. A disaster alert was issued for the surrounding county and in the nearby city of Hildesheim, which held its breath for two days as its levees threatened to overflow.
Other parts of Germany were badly affected too. Heavy downpours in Berlin in recent weeks overwhelmed the city’s sewer system. Drains ran over; a building was undermined and had to be temporarily evacuated.
Flooding of this magnitude could happen more frequently in the future. Scientists are observing a growing number of heavy precipitation events in Germany, combined with local flooding. The economic damage runs into the millions and sometimes billions, as in the case of the catastrophic Elbe River floods in August 2002. In Berlin and the surrounding state of Brandenburg, the heavy rains in late June caused about €60 million in damage, according to the German Insurance Association.
“Becoming more resilient to the effects of climate change is a mammoth task”
“Heavy downpours are increasingly causing substantial economic damage,” warned Peter Höppe, head of georisk research at Munich Re. The Intergovernmental Panel on Climate Change (IPCC), an institution of the United Nations, assumes that heavy rain events in Germany caused by climate change will become more frequent and more intense in the coming years. This means that larger amounts of rain will fall in shorter intervals. Cities, in particular, need to prepare for these weather conditions, as they are especially vulnerable to flooding due to dense development and the increasing prevalence of impermeable surfaces.
A Handelsblatt survey of Germany’s 10 largest cities shows that German government officials are devoting more and more attention to the subject of protection against flooding. “For many cities and municipalities, becoming more resilient to the effects of climate change is a mammoth task,” Mr. Höppe told Handelsblatt. Officials in Hamburg and Munich call it a major effort. It is no longer merely a question of investing in sewer systems to make them capable of absorbing larger amounts of water. “This is no longer an issue that can be addressed solely through urban drainage,” say Munich officials. Cologne, sorely afflicted by Rhine River flooding, is calling for “new ways of thinking and planning” to protect cities from floods in the future.
For instance, excess water could be collected on lower-lying city squares before it gradually flows into the sewage system. Parking lots with green space could also help by allowing more water to percolate into the soil. Terms like “water-sensitive city” and “sponge city” are being applied nationwide to potential solutions.
In new developments, planners are now incorporating areas that can be used as reservoirs, said Bodo Weigert, a water scientist in Berlin. “The challenge is to get the process of rethinking underway, especially in existing, often heavily sealed urban neighborhoods.” Upgrading the sewer system is not always an option, both for economic reasons and because of the lack of available space. Alternatives are needed to capture water on the surface more effectively, be it through green roofs or public squares that can be flooded temporarily. Underground rainwater retention basins, which prevent water from flowing too quickly into treatment plants, are now standard.
In a joint position paper, various association of cities, towns, and rural districts have called for a holistic strategy in the handling of rainwater, a so-called “heavy rain dialogue.” But that dialogue will be difficult to start without financial incentives, because it requires the participation of more than just municipal administrations and municipal drainage operations. “For example, how do I convince private property owners to install green roofs on their houses?” asked Berlin scientist Mr. Weigert.
Insurers say that private citizens also underestimate the threat of heavy rain. “Anyone can become a victim of natural disasters,” warned Jörg von Fürstenwerth, chairman of the German Insurance Association. This also applies far away from large rivers, and it could become truly expensive for the two-thirds of homeowners who currently lack insurance against natural hazards like heavy rain and flooding – especially those who have converted basements into home office space filled with technology. Bavaria was the first German state to announce that, beginning in July 2019, it will no longer provide financial assistance to uninsured flood victims if their homes were eligible for private insurance.
It is difficult to assess the cost of adjusting to climate change, and there are currently no reliable figures. “That sort of assessment would require the preparation of risk and weakness analyses for all German cities and towns, together with related planning of measures to be taken and cost estimates,” said environment ministry officials. The ministry is developing a strategy for a high-risk management plan that is expected to be ready at the national level by the spring of 2019.
Little more than isolated estimates exist to date. In a 2012 cost-benefit study, the Federal Environment Agency found that the annual adaptation measures for buildings to cope with heavy rain events could cost at least €1 billion nationwide.
The German Insurance Association believes it is necessary to modify building regulations, so that vulnerability to growing numbers of extreme weather events can be taken into account when selecting building materials and construction methods. Small bumps at the entrance to an underground garage can be somewhat effective, as can backflow traps to prevent water from entering the public sewer system. Municipal experts are aware of the need to take action. But then there’s also the question whether some measures make sense economically. “Using preventive measures to avert all damage,” said Munich Re expert Mr. Höppe, “is certainly not economically advisable.”
Silke Kersting reports for Handelsblatt from Berlin, focusing on consumer protection, construction, environmental policy and climate change. To contact the author: firstname.lastname@example.org.