Most of the country has had little to no rain in recent months. Now, as the islands prepare to host tourists, the pressure on water reserves is increasing, authorities, farmers, and scientists have stated.

The largest reservoir on the Greek island of Naxos has dried up, being useful only to the turtles swimming in its muddy waters. Downstream, seawater has infiltrated empty irrigation wells, affecting the island's precious potato crops.

To the south, on the island of Karpathos, authorities have imposed restrictions on filling swimming pools, while on the northern island of Thasos, officials are seeking a desalination unit to make seawater drinkable.

"There has been an intense lack of rain fall across the Mediterranean, and especially on Naxos, our surface reservoirs are empty", said the island's mayor, Dimitris Lianos.

Millions of tourists visit Greece every year to enjoy its ancient sites, pristine beaches, and turquoise waters.

However, the effects of climate change, including high temperatures, irregular rainfall, and wildfires, threaten the future of the country's most important economic engine.

This year seems particularly tense. After the warmest winter ever recorded, wildfires started unusually early, some in areas where it should have been snowing. At least six tourists, including well-known British TV presenter Michael Mosley, died last month as heatwaves swept across the country.

Climate experts fear the worst is yet to come. Andrea Toreti, coordinator of the European and Global Drought Observatory at the Copernicus Emergency Management Service, said that once the effects of drought become visible, it is too late to take action.

"We need to take preventive and preparatory measures because it's too late to do anything once the situation is in place," Toreti said.

The water deficit is evident in Naxos, a mountainous island with 20,000 inhabitants located in one of the most popular - and driest - parts of the Aegean Sea. Tens of thousands of tourists gather daily on its shores during the summer.

The island's two reservoirs hold 220,000 cubic meters (7.7 million cubic feet) of usable water, a third of last year's level and equivalent to only a few dozen Olympic-size pools.

Authorities have secured three portable desalination units that will treat seawater to make it drinkable, which Mayor Lianos said should cover the deficit for homes, hotels, and swimming pools.

However, farmers will not receive treated water and will have to rely on wells contaminated by seawater aquifers. Farmers have stated that this contamination occurs when wells are empty enough for saltwater to seep into them.

Stelios Vathrakokoilis grows the famous Naxos potatoes, prized in Greece for their buttery taste and protected from imitation under EU rules. This year, his production will be more than halved due to salty irrigation water, he said.

"It is a great disappointment because we, the people, failed to anticipate that climate change would knock on our door as well," he said, as a handful of workers harvested potatoes nearby.

Mediterranean countries, including Spain and Italy, are looking for ways to supplement their water supplies through desalination, but suppliers have said that this summer, units have been in short supply due to increased demand.

Even in Thasos, which is much greener than rocky Naxos, officials said they want to buy a unit for future use.

Greek-based manufacturer Sychem has not been able to fully meet customer demand this summer due to a shortage of key components and longer construction times, said CEO Alexandros Yfantis. New units should be available after September.

"Because the problem is everywhere, any temporary equipment has already been rented," Yfantis said.