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"The world's water resources are currently facing the greatest threat in the history of mankind," write aquatic ecologists in their recently published statement paper. More than one hundred professional societies of aquatic ecosystem research around the globe have signed the joint statement. In it, the researchers show the dramatic effects that climate change is having on aquatic ecosystems worldwide. They call for immediate concerted action by politics, business, science and society to halt the progress of climate change.

"Climate change is here - and it is leaving clear, partly irreversible traces in aquatic ecosystems," says Prof. Markus Weitere, President of the German Limnology Society (DGL) and Head of the Department of Stream Ecology at the Helmholtz Centre for Environmental Research (UFZ). (DGL) and head of the Department of Stream Ecology at the Helmholtz Centre for Environmental Research (UFZ). "We aquatic ecologists see the effects of climate change every day through our work. And the exchange with colleagues from all over the world shows: The problems reach around the globe - and they are massive." In a joint statement paper, professional societies from all over the world that study aquatic ecosystems have now compiled the effects of climate change on aquatic ecosystems and substantiated them with relevant studies. The paper was published on 14 September 2020. The DGL is one of the 110 signatory professional societies with more than 80,000 members.

"Freshwater ecosystems are among the most threatened ecosystems on earth." (quote statement paper)

Water is essential for the survival of all organisms. Aquatic ecosystems are therefore an indispensable basis for all life on earth. Due to climate change, however, water bodies are losing their ecological balance. "The extreme droughts we have experienced in Germany in recent years are signs of climate change and will become more severe," says Weitere. "The associated consequences for our water bodies are serious. For example, flowing waters carry less water, riparian areas and floodplain landscapes are falling dry. All this has a negative impact on the water ecosystem." The dwindling availability of water is also a problem for humans, as the groundwater level is sinking and drinking water reservoirs can no longer be sufficiently replenished.

Water quality is also suffering from the effects of climate change. "High temperatures and changes in water flow favour the eutrophication of water bodies, which leads to an increased development of algae as well as potentially toxic blue-green algae. "When this algal biomass is degraded, favoured by high temperatures, oxygen depletion occurs," explains Weitere. "This damages the organisms and can cause mass fish kills, as seen in the 2018 and 2019 droughts." In their statement, the professional societies further point to the risk of increased pollutant loads in water bodies. Rising temperatures can mobilise pollutants bound in permafrost soils and release them into water systems. "These and numerous other effects of climate change are leading to an increasing loss of biodiversity in water ecosystems," says Weitere. "This process is further exacerbated by immigrant species that benefit from changing conditions in water bodies and displace native species." Climate change is also leading to an increasing deterioration of water quality in the oceans. In their statement, the expert societies explain that shifts in species composition and abundance, for example, are already visible - with consequences for fishery yields and food security. "The global economic consequences of climate change should not be underestimated," says Weitere. "Failure to tackle climate change, loss of biodiversity and water crisis - these three issues have now been ranked for the first time among the top 5 risks of the coming decade by the World Economic Forum in its assessment of global risks."

"Governments, the public, industry, science and all other sectors of society need to prioritise and act in a concerted way to halt man-made climate change and prevent dire consequences."
(Quote statement paper)

What must be done now to slow down the progress of climate change and to keep the impacts as low as possible? In their statement paper, the aquatic ecologists call for a rapid, consistent and drastic reduction in the release of greenhouse gases. In addition, natural processes that sequester carbon must be promoted - e.g. by preserving, protecting and developing wetlands as natural carbon sinks. "Some consequences of climate change will be irreversible, however," says Weitere. "To best buffer the negative effects, we need to take regionally adequate measures." This includes promoting research and training in water ecology and ensuring capacities in water monitoring and management. The effects caused by climate change - eutrophication, oxygen depletion, pollutant mobilisation, immigration of alien species and loss of biodiversity - are not unknown in water ecology and can therefore still be managed in many cases. "Climate change is both a trigger and an accelerator. We can still make a difference - for that we have to take the scientific findings seriously and act boldly and decisively," says Weitere.

This statement is being released to coincide with the start of the American Fisheries Society (AFS) Virtual Annual Meeting on 14 September 2020 (afsannualmeeting.fisheries.org).

Statement (German translation): https://www.dgl-ev.de/cms/upload/dokumente/Stellungnahmen/200914_Statement_Wasse…

Scientific contact persons:

Prof. Markus More
Head of UFZ Department of Flowing Water Ecology / President of the DGL
markus.weitere@ufz.de

Original publication:
https://climate.fisheries.org/world-climate-statement/

Source: PM of the Helmholtz Centre for Environmental Research (UFZ) from 14.09.2020

Keywords:
Research, Climate emergency, Climate protection, News Blog Europe (without DE), Permaculture, Quarters, Settlements, City, Transition Town, UN (United Nations), Environmental policy, Water design, Ecology