Satellite data show low groundwater levels in Europe

8 Feb 2023 by The Water Diplomat

Satellite data have provided evidence that European groundwater is under pressure since the droughts of 2018, 2019 and 2022. In 2020, Eva Boergens and others, publishing in Geophysical  Research Letters, quantified the water shortages in Central Europe caused by the droughts of 2018 and 2019. In 2018 and 2019, Central Europe experienced a deficit of 112 Gigatonnes and 145 Gigatonnes respectively (112 and 145 billion m³). these represented 73% and 94% of the natural annual variation in precipitation between summer and winter.  These measurements are made possible by two satellites involved in the Gravity Recovery and Climate Experiment (GRACE) mission that has collected data since 2002. The authors state that ‘satellite gravimetry is the only remote sensing technique available today that provides quantitative estimates of water storage changes at regional to global scales’.     

Since that time there has been no significant rise in groundwater levels. The Institute of Geodesy at the Technical University of Graz in Austria come to this conclusion after analysing more recent satellite data. In 2022, a prolonged drought led to low river levels across Europe, with temperatures above 40⁰C across southern Europe and shortfalls of rain across central and southern Portugal, Spain; southern France; central Italy, Switzerland, southern Germany; a wide area across Ukraine, Slovakia, Hungary, Romania, Moldova, and large areas in the western Balkans.

Groundwater supplies 65% of drinking water in the European Union and 25% of agricultural water supply across the 27 member states.