Supporting the Earth’s Cycle: The Mysteries of Water

Water, which supports the Earth’s cycle as it moves from underground to the atmosphere, is an integral part of our lives. We drink it, use it, and take its presence for granted. But without water, we wouldn’t exist. Utilizing and coexisting with water is one of humanity’s great challenges. This article explores the various “mysteries” of water. It might slightly change your perception of this everyday element.

Water Has Been Circulating on Earth Since Ancient Times

Water evaporates to form clouds, falls as rain, and flows through various routes like groundwater, springs, rivers, and lakes, eventually reaching the ocean, only to evaporate again into water vapor. This is the fundamental water cycle. On Earth, water constantly circulates in different forms, with its total volume remaining nearly constant. In other words, the water we have today, like the water that flows from our taps, is the same water that has existed on Earth for eons, undergoing changes and movements over time. This is a fascinating way to understand the water around us.

Water Can Contain Various Substances

Pour water into a glass filled with ice, and the ice naturally floats. But this phenomenon is actually quite rare. Generally, substances shrink when cooled and expand when heated. As a liquid cools and solidifies, it becomes denser and heavier. However, water behaves differently—it becomes less dense and lighter when it freezes, allowing ice to float. If ice were heavier than water, oceans and lakes would freeze solid, halting the water cycle, and Earth might have become a “planet of ice” instead of a “planet of water.”

Water Contains More Than Just Water

Water has a unique ability to dissolve many substances. Although four-fifths of Earth’s surface is covered by oceans, which are primarily composed of water, almost all elements found on Earth are dissolved in the oceans. Sodium, chlorine, magnesium, as well as metals, organic compounds, and gases… although present in trace amounts, water’s ability to dissolve such a wide range of substances makes this possible. Doesn’t the saying “the ocean is the mother of all life” seem even more convincing now?

Speaking of Which, Alcohol is Also a Solution

In the past, alcohol was consumed more frequently than water in many European cities. Alcohol is an aqueous solution of ethanol, and its flavor is determined by “what is dissolved in the water.” Take whiskey, for example. When the clear, raw whiskey is aged in barrels for a long time, components from the wood dissolve into the liquid, giving it an amber hue and rich aromas. The process of “distillation,” which increases alcohol concentration and aroma, utilizes the property of water transforming into vapor when heated and returning to liquid when cooled. In this way, whiskey’s complex flavors are a product of water's properties.

Taking Responsibility for the Water Cycle

Producing whiskey, which relies on water’s properties, requires high-quality water. In Hokuto City, Yamanashi Prefecture, where the photos for this article were taken, is Suntory’s Hakushu Distillery. Here, single malt whiskies like “Hakushu” are made using groundwater rich in minerals, nurtured deep within the surrounding forests that support diverse life. However, simply drawing this water could lead to depletion. How can we sustain the groundwater cycle? Suntory has made its “Natural Water Sanctuary” a core business activity, carrying out reforestation and biodiversity conservation efforts in the forests that serve as water sources for its domestic factories. The company also actively works on visualizing groundwater flow, claiming to nurture more than twice the amount of water it draws through these efforts. Looking 50, 100 years ahead, protecting the “water cycle” is becoming an increasingly vital theme in corporate activities.

The Miracle of Earth’s Abundant Water

Let’s shift our perspective to outer space. Research has shown that water existed on other planets as well. For example, numerous traces of past water have been found on Mars’s surface, confirmed by planetary probes that have landed on the planet. Meteorites from Mars that have reached Earth also contain clay minerals, substances that could not exist without water. Meanwhile, analysis of Venus’s atmosphere has revealed that it is enveloped in water vapor.
However, there seems to be no other planet like Earth that still retains large amounts of liquid water on its surface. On Venus, high surface temperatures cause water to evaporate rapidly, while on Mars, temperatures are too low and gravity is weaker than Earth’s, resulting in the loss of liquid water from its surface. The unique combination of conditions that allow Earth to hold vast quantities of liquid water has created its expansive oceans, making it a miraculous planet that supports rich life.

In Search of Sustainable Water

As mentioned at the beginning of this article, according to the Ministry of Land, Infrastructure, Transport and Tourism (MLIT) website, the total amount of water on Earth remains nearly constant, but only about 0.01% of it is accessible fresh water for human use. Various factors can also contaminate this limited resource. Fresh water is essential for sustaining life, yet people are becoming aware that it is a “scarce resource” globally. Currently, efforts to secure “sustainable fresh water” are underway worldwide, with new technologies emerging. For example, technologies that extract water from atmospheric moisture or advanced filtration membranes that desalinate seawater are expanding the potential for “sustainable fresh water” supplies.
Japanese companies are also stepping up. Kurita Water Industries, which specializes in water treatment systems, has begun developing a “next-generation water recycling demonstration system” for use in space. This system purifies recovered urine to a level suitable for drinking, and has already cleared demonstration tests in space, paving the way for future manned space missions. Even as humanity ventures into space, the “water cycle” remains a crucial theme.

Water is a familiar and essential element for humanity. Therefore, understanding its properties, supporting the “water cycle” in various ways, and passing it on to future generations will become increasingly significant themes for enhancing global sustainability.