Water bodies under stress: Flash study illustrates effects of climate change on lakes in Germany

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Water bodies under stress: Flash study illustrates effects of climate change on lakes in Germany

– The study "Lakes and Climate Change" by Global Nature Fund and Grüne Liga e.V. examines the impact of global warming on domestic waters
– Rising temperatures and human pressure are changing the sensitive water ecosystems
– GNF: Decisive action is needed to protect unique habitats and the climate at the same time

An ecological dystopia - and an outlook
for the whole of Europe? The Greek
Lake Volvi fell completely dry in 2019.
Photo © Thies Geertz / GNF
Radolfzell, 27 July 2022: This publication is a wake-up call: Together with the Grüne Liga e.V., experts of the Global Nature Fund (GNF) have published the flash study "Lakes and Climate Change". Their result: Climate change strongly influences domestic waters, for example concerning the parameters temperature and precipitation. Particularly affected are those lakes, small water bodies and wetlands that are already heavily used by us humans for agriculture or recreation. In addition, the effects of climate change will worsen in the coming years and decades if we do not act decisively. The study is now available for download on the websites of the German Federal Agency for Nature Conservation and GNF.
Alarming data
Within the scope of the flash study, water bodies in Germany and other European countries were examined. The study concludes that many lakes in their current state are already heavily impacted by human activities and thus more vulnerable to negative impacts of climate change. Rising water temperatures, changing hydrology and increasing demands for use are reducing the resilience of water bodies to increasingly frequent extreme events.
For example, summer temperatures in European lakes recently increased by an average of between 0.29 and 0.38 degrees Celsius per decade. What supposedly pleases bathers actually means a continuous weakening of the eco- and climate system: e.g. the heat-induced increase in chlorophyll and cyanobacteria correlates with falling water levels in many lakes. Fish kills have been observed in some eutrophic, or excessively nutrient-rich, waters due to oxygen deficiency and high concentrations of ammonium and ammonia. Climate-induced fluctuations in water levels also have a significant impact on the living conditions of waterfowl, some of which have to find new breeding grounds.
Approaches for the conservation of unique ecosystems
Udo Gattenlöhner, GNF executive director and co-author of the study, says about the results: "In times of global warming and summer drying, lakes and wetlands need better protection. This means above all the consistent avoidance of pollutant discharges, the renaturation of shores and extremely restrained water use. Planned shoreline armoring must become more the subject of strategic environmental assessments, given the limited carrying capacity of lakes. We need more extensive buffer zones, as well as more unused riparian strips and near-natural shallow water zones."
Peatlands, which are considered particularly endangered wetlands and whose preservation also plays an important role in the fight against climate change, should also receive more attention. Although peatlands represent only seven percent of the agricultural land used in Germany, they are responsible for 37% of total agricultural greenhouse gas emissions. For this reason, so-called paludiculture has already been tested and promoted for several years: an approach to simultaneously enable the use of the peatland ecosystem and the restoration of its natural, wet state.

Download the flash study "Lakes and Climate Change" (in German)


Global Nature Fund (GNF)
International Foundation for Environment and Nature
Udo Gattenlöhner, Managing Director
Fritz-Reichle-Ring 4
78315 Radolfzell
+49 7732 9995 80