When a single event becomes the turning point and decisive moment for how a community approaches a factor of their environment: this is certainly what happened in 1872, when during the night of November 12th, a disastrous storm surge hit the southwestern Baltic Sea coast. Coastal residents faced a natural event they had never anticipated.
This occurrence was the birth-hour of modern coastal protection in the region, which includes mainly the coasts of Denmark and Germany. Coastal researchers, politicians, and the media regard it as the heaviest storm surge the region ever experienced, which, considering the fact that scientific recording of water level rise and wave heights only started in the nineteenth century, seems to be a hasty conclusion. Nevertheless, since the water level rose up to 3.30 meters above average sea level this event started an initiative to build strong dikes on the coasts to confront this impact.
In mid-November 2022, an excursion aimed to visit the locations that were impacted in 1872 with a subsequent “Baltic Sea storm surge 1872 – 150th memorial conference” following directly afterwards. In some locations, like Kramnitse in Denmark, coastal protection measures implemented as a direct response to the catastrophe were still visible. Other observations points were examples for contemporary installments in anticipation of the recurrence of a similar event, which was also a possibility discussed during the conference. Exactly 150 years after the waves of the Baltic Sea had caused at least 271 casualties, destroyed many houses, and rendered 15,000 people homeless, both undertakings also served as commemorating events which I had the opportunity to participate in.
The journey took us from Køge on Zealand to the islands of Lolland and Falster in Denmark, where dikes stretching many kilometers were erected after 1872, and along the German coasts of the federal states of Schleswig-Holstein and Mecklenburg-Western Pomerania, which also faced immense destruction. No matter where we stopped for closer inspections, the central problem of dwindling flood memory, which enables the process of “flood dementia” in these regions, came up.
The term “flood dementia” describes the process of a community being risk-aware shortly after a flood happens, but forgetting about this risk again as this event moves further away into the past. Flooding then does not recur often enough to keep the memory awake.
Forgetting natural disasters of course is a risk in itself. To add to this, in the places we visited, a conflict of interest was often obvious: tourism is a big economic factor everywhere, and a sea view blocked, for instance by dikes, is highly undesirable. People are mainly focused on benefitting from the landscape rather than their own protection. This is made visible by the fact that in Dahme (Schleswig-Holstein) there are touristic infrastructures like restaurants and pools still located on the sea side of the dike, to be closer to the popular beach. If it would be allowed, private housing would also be built here, but public authorities have put rules in place which prevent the building of housing structures between dike and sea to minimize the risk level.
Where there are no such strict rules based on the flood risk in place, the inhabitants have to face the consequences of what might also be called a willful ignorance. One example is a recently developed housing area in Rostock (Mecklenburg-Western Pomerania) located in a part of the city which has been prone to flooding for centuries, where still the inhabitants chose, knowingly or unknowingly, to live, and have to accept regularly flooded parking garages and homes now. They also get to enjoy the desired proximity to the local riverside, but wouldn’t it be better to be aware of and accept natural boundaries? The storm surges of the past centuries, it seems, have yet to secure a place in the local collective memory.
This is where the importance of the cooperation of the natural sciences and humanities became more and more apparent. Since the pre-tour and the conference had been organized by the German Coastal Engineering Research Council, the majority of participants consisted of natural scientists, mainly coastal and civil engineers. Together with a colleague from the field of sociology and myself as a historian, we were the two “exotics,” interlopers from the social sciences and humanities.
While the bigger part of the group was understandably more focused on the coastal protection installations we visited, I was very curious about how they viewed the historical event under examination and what they made out of it—what importance they would assign to it. Investigating several historical storm surges in my own research, I knew that such events are hard to grasp within scientific work since there is very little reliable data, so I was unsure about what relevance my scientist colleagues would give these events. The storm surge of 1872 had been investigated by coastal engineers already in the 1990s and still is an important part of water level estimations for the future in the Baltic Sea. During the excursion and conference, I personally got the impression that there is a very open approach in the field of coastal engineering to take information from historical sources into consideration as much as possible when it when trying to make forecasts for future storm surges.
The vast majority of those present, regardless of discipline, agreed that the storm surge of 1872 should be viewed as a singular event only in the short-term perspective. The common view was that, yes, it was catastrophic, but certainly not the only event of that magnitude. Extending the period of observation as far into the past as possible must and will be a common goal of the disciplines in the future.
An important takeaway from the excursion and conference was how future-oriented environmental history truly can be. Environmental history can be important and useful, here specifically in the context of cooperation between coastal engineers and historians. Measurement series of the former can be usefully supplemented by data and knowledge that can be gathered from historical documents by the latter, thus enabling what has already been started: the inclusion of events before the start of systematic recording.
Risk awareness and the memory of flood events play an important role in flood protection—but what does one do when memory has faded to the point that those who have to be protected may not be fully aware of their own need for protection? The social sciences can and should contribute valuable work here, strengthening and increasing the effectiveness of flood protection measures.
The fact that memory and awareness definitely do exist to a certain extent is shown by the implementation of the excursion and conference. But it is mainly those who are already professional experts engaged with the subject on a daily basis that are involved in such efforts. What about those who are not—those outside this bubble? The media also paid attention to the anniversary: newspaper articles, television reports, and radio programs on the subject were broadcast, so that a wider audience came into contact with the subject. Whether raising awareness for historical floods and therefore flood risk is sustainable in the long term remains to be seen; the next flood anniversary on the southwestern Baltic coast, marking 400 years since a 1625 catastrophe, is fast approaching.
 Jürgen Jensen, Mai Habib, and Simon Beckmann, “Best estimates for historical storm surge water level and MSL development at the Travemünde/Baltic Sea gauge over the last 1,000 years,” Die Küste 92 (2022).
 Susanne Kailitz, “Diagnose Hochwasserdemenz,” Zeit Online (June 11, 2013).
As flood dementia is a direct translation of the term used in the German discourse, “flood amnesia” can also be used alternatively, since it describes the same process. In addition to “flood dementia,” the already established term “shifting baseline syndrome” also can be used to describe what happens when an original reference point is lost, see Daniel Pauly, “Anecdotes and the shifting baseline syndrome of fisheries,” Trends in Ecology & Evolution 10 (1995), 430. This is also the case at the Baltic Sea coast. Because extensive and scientifically reliable historical sources are missing and collective as well as personal memory only reaches so far, the coastal inhabitants only get a distorted imagination of what the Baltic Sea is capable of and what the time intervals of disastrous natural events are.
 Jürgen Jensen and Andrea Töppe, “Untersuchungen über Sturmfluten an der Ostsee unter spezieller Berücksichtigung des Pegels Travemünde,” Deutsche Gewässerkundliche Mitteilungen 34, vol. 1 (January 1990): 29-37.
 Danish local media collected sources and reports about the event: “Stormfloden i 1872,” Folketiende. German media did broadcasts and other contributions, see e.g. Jürgen Opel, “Jahrtausendflut an der Ostsee: Hochwasser bis heute,” NDR (November 23, 2022).
*Cover image: Drawing of destruction of a barn in Niendorf during the storm surge of 1872. By Carl August Heinrich Ferdinand Oesterley. Scan of the original work via Wikimedia Commons.
*[Cover image description: Black and white illustration of a partially destroyed barn and seawater flooding the area around the barn. Four or more people are barely visible, clinging on to debris or landforms. Waves crash around fence posts, with a stormy gray sky and a few seagulls overhead.]
Edited by Anna Guasco, reviewed by Aly Kreikemeier.