Today is World Water Day, an occasion for us to reflect on how we exploit and treat our most important resource.

Fresh water resources such as rivers and lakes are deteriorating worldwide. Many rivers have dried up, and water volumes of major rivers have decreased dramatically in the past few decades, according to a report by the United Nations.

There is the saying that all water flows into the ocean. The sad fact now is that many rivers cannot flow into the ocean as they did before, as the volume of water has so drastically decreased.

The Yellow River, China's second longest, stopped flowing into the ocean from early 1970s to late 1990s.

Statistics show that the number of fresh Arctic lakes decreased from 10,008 to 9,712 from 1973 to 1998. In China alone, nearly 1,000 inland lakes dried up in the past five decades.

What we humans have done to these rivers and lakes has contributed greatly to this deteriorating situation.

The facts suggest that we do not really know how to exploit water resources.

Human existence and development is closely related to water. Back in ancient times, our ancestors established their settlements by rivers or lakes and built cities or castles by waters.

Some civilizations declined or became extinct simply because the lakes or rivers they relied on dried up.

We used to believe that we could change waterways for our immediate benefits, we could build dams to block water for our use and we could treat water in whatever way that we thought would bring us immediate benefits.

We have been quite cavalier towards nature, believing that we can tame it as we can a domestic animal.

Today desert has conquered or is encroaching on areas that used to be inland lakes or rivers, the biological environment is becoming worse in most delta areas because of less fresh water flowing into the ocean, and degradation of wetland owing to a lack of fresh water from rivers has affected the climate in a negative way.

We humans are constantly caught in a dilemma between development and protection of resources.

Some believe that development should always come first, arguing that nothing could be as important as the survival of man.

However, we must take a more long-term view.

UN experts warned that 2.7 billion people face a critical shortage of drinkable water by 2025. It is high time we exercise more caution in the way we exploit water resources, and develop more effective measures to protect our rivers and lakes.

A population of 6.5 billion exerts heavy pressure on the environment and resources, and the pressure will be even heavier in the coming two decades.

A proverb says we will never know the worth of water until the well is dry.

We hope the reality is not as cruel as it describes, and all of us get to know the worth of water before the well is dry.

(China Daily March 22, 2006)