Lunar Water Scarcity Limits Large-Scale City Settlement, Scientists Warn

Recent discoveries of water ice at the Moon’s poles have ignited speculation regarding the feasibility of establishing permanent human settlements, including industrial zones and cities. However, a new study published in Frontiers in Space Technologies by Dr. Martin Elvis and Dr. Jonathan McDowell indicates that even under optimal conditions, a population of one million would exhaust local water supplies within 100 years.

The presence of water in the dark, permanently shadowed craters near the lunar poles has triggered a renewed interest in lunar colonization. These “cold traps,” which have remained below 110 Kelvin for approximately four billion years, preserve water ice delivered by ancient asteroid impacts. Since 2013, orbiting missions have estimated that up to one billion tons of water may exist in these regions.

This resource fundamentally changes the logistics of lunar habitation. Unlike current missions to the International Space Station, where every drop of water must be imported from Earth, a lunar settlement could theoretically utilize local ice to grow food, provide sanitation, and support daily life. Such prospects have fueled ambitious visions from figures like Jeff Bezos and Elon Musk, who advocate for moving heavy industry and establishing self-sustaining cities on the Moon.

The researchers noted that energy generation poses no significant barrier to sustainability. The rims surrounding these permanently shadowed craters, often mistakenly called “peaks of eternal light,” receive nearly continuous sunlight. Dr. Elvis explained that kilometer-high towers equipped with photovoltaic arrays could generate three gigawatts of electricity, potentially supporting industries such as AI data centers and manufacturing.

However, the water analysis presents a stark reality check. Without recycling, a city of 100,000 to one million people would deplete available water in just a few years. Even assuming a highly efficient 98% recycling rate—comparable to ISS technology—a one-million-person settlement would only last slightly over a century. Furthermore, current estimates suggest the actual water volume is roughly 30 times less than one billion tons, which would reduce that timeline to mere decades for large populations.

Smaller communities, such as a village of 1,000 residents or a town of 10,000, could remain sustainable for centuries. To support larger cities, the authors propose several solutions: improving recycling efficiency fivefold, reducing consumption through vertical farming, importing water from asteroids, or discovering additional surface deposits. The latter option is considered the most promising, as current surveying techniques only penetrate a few meters into the regolith, whereas deeper layers may contain substantial ice reserves.