Today, only the eldest inhabitants of the Danube Delta recall that, in the past, you could skate on the river practically every winter; since the second half of the 20th century, Europe’s second-largest river has only rarely frozen over. The reason: the rising winter and water temperatures in Central and Eastern Europe, as a German-Romanian research team recently determined. Their analysis has just been published in the online magazine Scientific Reports.
Today, only the eldest inhabitants of the Danube Delta recall that, in the past, you could skate on the river practically every winter; since the second half of the 20th century, Europe’s second-largest river has only rarely frozen over. The reason: the rising winter and water temperatures in Central and Eastern Europe, as a German-Romanian research team recently determined. Their analysis has just been published in the online magazine Scientific Reports.
In the Romanian harbour town Tulcea, an ice diary is dutifully maintained. Since 1836, the Danube Commission has recorded every winter in which the river froze over, how long the river was covered by a solid sheet of ice, and the day on which the ice began to break up. Until roughly 70 years ago, the ice archivists reported ice cover almost every year. But since the middle of the 20th century, the entries in the column “ice” have become few and far between: between 1951 and 2016, Europe’s second-largest river only froze over ten times. Mathematically speaking, that means less than one in six winters. A comparison with regions farther upstream shows that in Tulcea, the entryway to the Danube Delta, the river freezes longer and much more frequently than e.g. in Budapest, Hungary. So what explains why the residents of Tulcea haven’t been able to skate on the Danube for the past 70 years?
A German-Romanian research team has sought to answer this question. “When climate researchers talk about ice and global warming, most people think of the Greenland Ice Sheet or the sea ice on the Arctic Ocean. Most of them don’t realise that the amount of winter ice on Europe’s seas and rivers is an equally important indicator for a changing climate,” explains Dr Monica Ionita, a climate researcher at the Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research (AWI).
Read more at Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research
Photo Credit: falco via Pixabay
