“If you see me, weep.” This is the ancient message revealed by falling water levels in Europe.

If you’d walk along the Elbe river in Europe, you might chance upon something very unusual: low water levels have revealed so-called Hunger Stones — carved inscriptions marking drought-heavy years in the past centuries. The message is simple: to commemorate historic droughts, and warn of their consequences; one such rock reads “Wenn du mich siehst, dann weine”, which is German for “If you see me, weep.”

Over a dozen of these hunger stones can now be seen near the northern Czech town of Decin, close to the German border.

It’s not the first time the rocks have been observed. They were actually described by a study in 2013, and although the names of the carvers have been lost through the shroud of time, the message is clear.

“It expressed that drought had brought a bad harvest, lack of food, high prices and hunger for poor people. Before 1900, the following droughts are commemorated on the stone: 1417, 1616, 1707, 1746, 1790, 1800, 1811, 1830, 1842, 1868, 1892, and 1893.”

But aside from the obvious message (which largely says “if you can read this you’re having a nasty drought”), the hunger stones also lamented the results of the drought. For instance, the 2013 study describes one such rock which “expressed that drought had brought a bad harvest, lack of food, high prices and hunger for poor people,” immortalizing the hardship the local people had to go through.

The rocks have become a tourist attraction, aside from raising some scientific interest. But perhaps the most important aspect of the stones is their original purpose — to tell us that if we can read the message, there’s a big drought.

Europe’s nigh-unprecedented heatwaves have led to record high temperatures in several areas of the continent, and the drought has also been taking a dramatic toll. Although it’s very tricky to establish a clear cause-effect relationship between rising temperatures and this year’s drought and heatwaves, it seems likely that climate change is, at the very least, amplifying the problem.

Our forefathers left behind an ominous warning for us — and we’d best heed it. Otherwise, we can start carving our own years into the rocks.