Water is vital for life. It covers around 70% of the Earth’s surface. The human body is comprised of 60 to 70% water. To obtain water, we take it from lakes, rivers, streams, and underground aquifers. These water sources nourish diverse plants and animals, including Romer’s tree frogs and Hong Kong paradise fish, which are endemic to Hong Kong. For people in this metropolis, water seems to be easily accessible. However, did you know we are facing a freshwater crisis? Despite the ample amount of water on this planet, only 2.5% is freshwater. And much of this freshwater is either locked as ice on mountains and in polar regions, or hidden underground. This makes the freshwater available for our use less than 1%!
Freshwater is not everywhere. It is unevenly distributed across different climates and topography. Hong Kong has a high population but few natural rivers or lakes. We depend on the water imported from Dongjiang in Guangdong province, and the rainwater collected in reservoirs. Having been piped and pumped, 2.6 million m³ of freshwater is supplied to over 7 million Hong Kong people every day. We use it for many purposes such as drinking, cooking, cleaning, and gardening. Water is not only necessary for households, but also for all sectors to provide goods and services. For example, agriculture uses 70% of all freshwater withdrawn by humans. As our demand stays high and the population grows rapidly, more and more freshwater is needed. The competition for this limited resource is intensifying. What would happen if Dongjiang runs dry?
While we are fortunate to have a constant water supply, water scarcity happens on every continent. Nearly 20% of the world’s population lives in areas that are short of water. The supply is not guaranteed even for those who live near bodies of water. The Yellow River and Yangtze River in China are at risk as the upper tributaries dry up. In the United States, a huge aquifer was extracted and exhausted for irrigation. These alarms are amplified by pollution, which deprives us of clean water, as well as climate change, which alters rainfall patterns and evaporation rates. In 2030, it is estimated that the current water supply in Hong Kong may fail to meet our demand. Nearly half of the world’s population could face high water stress by 2030. Apart from us, plants and animals will also be threatened. Since 1970, the populations of freshwater species have declined by half. The freshwater crisis is putting life at stake.
Thanks to the water cycle, freshwater is replenished and cleaned gradually. As Mohandas Gandhi said, “There is enough on this planet for everyone’s need but not for everyone’s greed.” With the population rising, water can quench the thirst of the world if we each get a smaller share. To reduce our demand, efficiency is the key. To save clean water for all humans and for healthy aquatic ecosystems, protection of water sources is a must.