Potsdam-China and back: "When climate projections return home"

02/05/2018 - China's Guanting region is threatened by water scarcity - how water and land can be used sustainably was explored over several years by a German-Chinese team headed by the Potsdam Institute for Climate Impact Research (PIK). Now the scientists published a book on their findings. The researchers applied computer simulations on climate change and water cycles in Brandenburg to the Guanting region. They thereby gained valuable new methodological insights for refining their models - and now bring this back to Germany: a learning process across continents.
Potsdam-China and back: "When climate projections return home"
PIK hydrologist Tobias Conradt presents the Guanting Book to Gao Jianwen from the "Haihe River Conservancy Commission". Photo: PIK

“For the Haihe River Basin in Guanting, the issue of decreasing rainfalls is exceptionally crucial – this is why we looked yet again at this aspect in the computer simulation used so far," says project leader Frank Wechsung from PIK. “It showed that extreme rainfalls are likely to increase and flood risks in this region are not to diminish - and at the same time water scarcity during dry periods remain a serious problem”. The previously used STARS model continues to provide information to analyze the region's sensitivity to drier summers; however, it had overall to a too large extent indicated the reduction in total rainfall, as new calculations show. The underlying methodology of the STARS model was reviewed; partial weaknesses of some assumptions and the resulting consequences were published.

On this basis, the researchers had another look at previous simulations on the Eastern German river basins of Havel, Spree and Elbe and repeated those that they thought they could further improve. The analyses have shown that the precipitation decline in summer is limited to a shorter period of time and is less extensive than previously expected. “A decline in low water discharges will likely still be observed for large parts of the draining Elbe region in East Germany, but it would be less severe and would then primarily be caused by rising temperatures and the reduced snow storage capacities in the low mountain range”, says Wechsung. "We are glad that we have learned how to gain new insights in this respect."

More information:

Wechsung F & Schellnhuber HJ (2018). When climate projections return:
Unusual insights for German rivers from a climate impact study for Beijings Guanting region, Short Communication 8p., published by PIK, [DOI: 10.2312/PIK.2018.002]. Weblink: https://doi.org/10.2312/PIK.2018.002


Frank Wechsung, Stefan Kaden, Michael Venohr, Jürgen Hofmann, Jens Meisel, Zhenci Xu (2017): Sustainable Water and Agricultural Land Use in the Guanting Basin under Limited Water Resources. Schweizerbart Science Publishers. Link: https://www.schweizerbart.de/publications/detail/isbn/9783510653256/Sustainable_Water_and_Agricultural_Land