As heatwaves continue to grip Europe, communities are turning to a variety of ingenious, natural cooling systems that have been in use for centuries, offering an alternative to modern air conditioning. These methods utilize the Earth's geology and natural resources to maintain comfortable temperatures even when external conditions become extreme.
In the Loire Valley of France, the troglodyte village of Trôo offers a unique example of natural climate control. Homes carved into the rock maintain a stable temperature of around 20 degrees Celsius (68 degrees Fahrenheit), regardless of outdoor temperatures that can exceed 35 degrees Celsius (95 degrees Fahrenheit). The thick layer of surrounding rock provides natural insulation, keeping the interiors cool.
Naples, Italy, is exploring ways to revitalize its historic underground infrastructure to combat urban heat islands. The "Cool City" project aims to reactivate ancient aqueducts, cisterns, and fountains from the Greek and Roman periods. By bringing cool water and air from these subterranean resources, the initiative seeks to create new public spaces that promote ecological sustainability and provide relief from rising temperatures, a necessity as the city anticipates prolonged periods of extreme heat by mid-century.
Switzerland's Ticino region features "grotti," natural caverns formed by landslides. Initially used to store wine, cheese, and produce, these naturally cool spaces have also been converted into eateries. Locals have further utilized these grotti by expanding them and building homes on top, allowing for airflow from below to regulate indoor temperatures.
In Slovenia and Austria's Julian Alps, natural geography plays a role in maintaining cooler temperatures. Towns like Lake Bled benefit from katabatic winds, or mountain breezes. During the day, mountain slopes heat up more slowly than the valleys, causing cooler air to flow down into the towns, thereby moderating the climate.
Italy also employs a historic geothermal cooling system in six 16th-century villas in Costozza, Vicenza. This system uses underground ducts connected to natural caves to passively cool the villas. Studies show that this ancient method can maintain indoor temperatures below 20 degrees Celsius, even on hot summer days. The system's self-adaptive nature, where airflow increases with outdoor temperature, makes it comparable to modern climate control systems and offers a model for using geothermal resources to improve comfort and reduce energy consumption in contemporary buildings.