The sea suddenly withdraws, the harbour empties in ten minutes, and then the water comes back with force. This summer the Adriatic is behaving unusually - meteotsunamis have appeared one after another at a string of places, and climatologists say that is not normal. The sea that all of us on this coast share is sending a signal worth listening to.

A meteotsunami is not an ordinary tsunami. With a classic tsunami the culprit is an earthquake; with a meteotsunami, it is the sky alone - sudden atmospheric changes that trigger oscillations of the sea level. Oceanographer Mirko Orlić explains the mechanism with an image from childhood: „At the right moment, the movement of the body increases the amplitude of the swing each time. It is similar with a meteotsunami.”

When the speed of the atmospheric wave coincides with the speed of the sea wave, the amplification is tenfold. If, on reaching the coast, the period of the wave coincides with the natural oscillation of the bay, another tenfold amplification follows - and a single disturbed centimetre turns into a wave several metres high. The greatest danger is not the waves themselves, but the powerful currents as the sea withdraws. The harbour can empty completely in ten minutes, before the water rushes back.

The figure that worries is the frequency. The catalogue of meteotsunamis that Orlić created shows that such phenomena usually happen once a year or less. And now, in just eight days, a meteotsunami has appeared at a string of places along the coast. „Three days with a meteotsunami within eight days, whereas they normally happen once a year or less. This clearly shows that something unusual is happening this summer,” Orlić warns.

The cause, science says, is called climate change. The temperature difference between the Arctic and the equator is weakening, the jet streams are slowing, and the atmospheric waves are becoming slower and more pronounced. This is not a distant theory for the polar bears - it is the sea we look at every summer from our beaches, only now it is behaving differently from how we remember.

The Adriatic is not a Croatian or Montenegrin or Albanian sea - it is shared. When it starts behaving unpredictably, the story concerns everyone who plans a summer on this coast. And while science patiently measures the waves, the old question remains: how many signals do we need before we stop pretending that the climate is someone else's problem?