The beautiful dry Danube

Drier summers and warmer winters will ultimately dry out the major European rivers Rhine, Elba, Danube… As Alpine glaciers melt, major flooding is to be expected, but ultimately, the warmer and drier climate will make our rivers fragile shadows of what they once were!

According to the European Environment Agency, most of Europe’s glaciers are in retreat1. Since 1900, glaciers in the Alps have lost approximately half of their volume – with clear acceleration since the 1980s. Between 2003-2017 only, Alpine glacier volume decreased by 20%! And the projections for the future are pretty bleak. If we don’t take direct action to stop CO2 emissions, the size of European glaciers will decline by 50% by 2050 and up to 89% by the end of the century1:12. The Alps’ glaciers and snow provide most of the water for lowland Europe and are the source of some of the largest European rivers such as the Rhine, the Rhône, the Po and tributaries of other major rivers like the Danube.

Losing the ice and snow covers of European mountain ranges is changing runoff regimes we used to take for granted. We’re seeing higher flow rates in winter causing severe floods, and consequent, lower summer flow rates3 – a trend observed since the 1960s1:2. Unfortunately, low summer discharge coincides with the highest water demands for irrigation, causing regular water shortages. In July 2018, low water levels on the Rhine made parts of it non-navigable. This halted production in places, increasing manufacturing costs and disrupting supply chains in the industrial heartland of Europe. The result was a considerable impact on the German economy: shaving at least 0.7 percentage point off its economic growth4! And it isn’t just about economic cost; we’re also witnessing dramatic environmental consequences. Increased water temperatures and droughts are killing thousands of fish5 and creating massive disturbance in freshwater ecosystems6.

In the near future, yearly river flows are expected to rise in Western and Northern Europe (mostly due to increased precipitation in winter) and to drop in Southern, Central and Eastern Europe1:3. However, summer flows are expected to decrease everywhere as a result of droughts and heatwaves. Ultimately, as the glaciers disappear, the European rivers will dry out. According to the European Environmental Agency, by the end of the century, most European rivers are expected to have a water volume deficit of more than 80% compared to their size at the end of the 20th century1:4. The Beautiful Blue Danube and other iconic European rivers will slowly vanish. Only by taking serious and immediate action to reduce our CO2 emissions can we prevent this dire future. We need to act now!

References

  1. EEA Report 1/2017, 25 Jan 2017, Climate change, impacts and vulnerability in Europe 2016, European Environmental Agency, ISSN 1977-8449. ↩︎ ↩︎ ↩︎ ↩︎ ↩︎

  2. Zekollari et al., 2019, Modelling the future evolution of glaciers in the European Alps under the EURO-CORDEX RCM ensemble, The Cryosphere 13:1125-1146. ↩︎

  3. Brunner et al., 2019, Present and future water scarcity in Switzerland: Potential for alleviation through reservoirs and lakes, Science of The Total Environment 666:1033-1047. ↩︎

  4. Gordon, 23 Jan 2019, Germany’s Dried-Up Rivers Cut Growth But the Rebound Is Coming, Bloomberg. ↩︎

  5. Jäger, 10 Aug 2018, Dying fish and drying rivers — consequences of Europe’s summer heat wave, Deutsche Welle. ↩︎

  6. O’Briain 2019, Climate change and European rivers: An eco‐hydromorphological perspective, Ecohydrology 12:e2099. ↩︎