Rhine in danger: water temperature could rise by 4.2 degrees by 2100!

Rhine in danger: water temperature could rise by 4.2 degrees by 2100!

The Rhine, one of Europe's most important waterways, is facing serious changes caused by climate change. The water temperature of the Rhine is continually rising, which has serious consequences for ecosystems and economic uses. According to a current study by the Federal Institute of Hydrology (BfG) and Deltares, a temperature increase of up to 4.2 degrees Celsius is expected by the end of the century compared to the average values ​​from 1990 to 2010. This will not only affect water quality, but also worsen living conditions for many aquatic organisms.

In spring 2025, the water level of the Rhine was already well below the long-term average, and the President of the International Commission for the Protection of the Rhine (ICPR), Dr. Miriam Haritz, expressed concerns that such low water phases could occur more frequently in the future. Historical series of measurements evaluated from 1978 to 2023 show a clear warming trend in the Rhine, especially in the southern sections from Switzerland to Karlsruhe.

Increased water temperatures and their effects

The study shows that the annual mean temperatures in the Rhine could rise by 1.1 to 1.8 degrees by the middle of the century and will continue to rise to 2.9 to 4.2 degrees by 2100. This means that the number of days with temperatures below 10 degrees could fall from the current 170 to just 104 days, while the number of days with temperatures above 21.5 degrees could increase from 32 to 106. Even temperatures between 25 and 28 degrees could be reached on almost 50 days a year.

The increase in temperature is mainly caused by rising air temperatures. While human heat inputs, such as those caused by cooling water from power plants, have decreased, this has not stopped the rise in water temperatures. This could lead to long-term restrictions on water use, particularly for cooling water consumers, as capacity is reduced by the higher water temperatures.

Ecological challenges and adaptation strategies

Rising water temperatures could have significant impacts on aquatic life. Critical temperature thresholds threaten to cause ecological damage, in particular heat stress in aquatic organisms and a reduction in the solubility of gases that are essential for the health of animals in the Rhine. In addition, warming during the winter could promote the spread of invasive species, which would further threaten the ecological balance.

In order to meet these challenges, the states in the Rhine catchment area are working on adaptation strategies to reduce the climatic impacts. The aim is to preserve and strengthen the ecological functions of the Rhine. Measures could include, among other things, the creation of shady retreat areas and the renaturation of riparian forests in small tributaries.

In summary, the Rhine faces a challenging future in which human and ecological needs must be reassessed. Climate change is already affecting water temperatures and will continue to cause significant changes in the coming decades. How World and BfG report, it is critical to take proactive measures to address the impacts of climate change on this important river.