For the first time the ICPR has presented a report on the estimation of the effects of climate change on future Rhine water temperature development in the near future (2021-2050) and the far future (2071-2100). This estimation is based on the air temperature development as defined in the scenario study for the discharge regime of the Rhine (cf. <link file:3078 _blank download den einer>ICPR Report No. 188, 2011). The report is available in a short and a long version and supplements the IKSR publications on the long-term Rhine water temperature development in the period 1978 -2011 (<link file:365 _blank download den einer>ICPR Report No. 209, 2013) and on the possible effects of these changes on aquatic biocoenoses (<link file:577 _blank download den einer>ICPR Report No. 204, 2013).
During the reference period 2001-2010 the course of the water temperature (related to average August values) without heat input displayed a gradual warming on the stretch of the Rhine between Basel and Werkendam (greatest increase in water temperature in the Upper Rhine to Worms). If we take into account 50% of approved heat input in the reference period, this leads to an additional average warming of around 1°C, especially downstream from Worms.
A comparison of the average August water temperatures along the Rhine longitudinal section between the reference and the near future shows an increase in average August water temperatures of around 1.5°C, while the increase in the far future is around 3.5°C. This warming is due to climatic factors, without any additional effect due to significant heat input.
In the near future the number of days on which the water temperature shall exceed 25°C will increase in comparison with the reference; in the case of low discharge by up to double (e.g. at Worms between 11 and 29 exceeding days). In the far future the days exceeding 25°C will increase strongly.
This report summary provides an overview of the most important results of the long English-language version of the report “Estimation of the effects of climate change scenarios on future Rhine water temperature development” (cf. <link file:606 _blank download den einer>CIPR Report No. 214), which contains the complete results of the simulation calculations.