Can we save the world by turning off the water tap?

The state of Brandenburg is one of the areas with the most lakes in Germany. Declining water levels have been observed in many lakes in recent years. / photo: Johannes Eber

A few days ago, a friend in Berlin told me she had significantly reduced her water consumption. She would, for example, only leave the water running at the beginning and end of taking a shower. And when she pours a glass of drinking water from the tap, she doesn’t let the water run until it’s cold but instead catches the lukewarm water in a bowl that she uses to water the flowers. 

I asked her why she wanted to save water. She replied that it is raining so little everywhere at the moment and that it is, therefore, important to save water.

Saving water against the drought – that sounds plausible. But does it really help? The answer of the friend irritated me in two respects. First, Berlin is quite far north (between the 51st and 52nd degree of longitude), and Germany is considered a water-rich country. Is there really a water shortage in Germany? Second, do we really consume water in the sense that when we’ve used it, it’s gone? Isn’t it much more of a cycle product? You take it from the ground, use it, and put it back to the ground (hopefully cleaned). And if water was such a cycle product, which consequences would its usage have for the environment?

In other words: Is the water-saving behaviour of my friend beneficial for the environment and fellow human beings? Or does it only benefit her in the sense that she believes she has contributed to a better environment?

First of all, water is an exceptional resource in the sense that it is the most important one. We can’t survive without water. At the same time, water is more abundant than anything else. Two-thirds of the earth’s surface is covered with water. 

Sure, most of the water is saline and therefore unusable for humans. The freshwater available to us (in the form of surface water in rivers and lakes or groundwater) is just around 1 per cent of the total water on earth. But only a third of that amount is used and reused by humanity. So, at least in theory, more than enough freshwater is available to meet the world population’s demands. 

In practice, unsurprisingly, it is different. Due to the unequal geographical distribution and especially the unequal water consumption, water is a scarce resource in some parts of the world and for some parts of the population.

In fact, the problems are enormous. According to UNICEF, an agency of the United Nations responsible for providing humanitarian and developmental aid to children worldwide, four billion people experience severe water scarcity for at least one month each year. This is almost two-third of the world’s population. And over two billion people live in countries where water supply is continuously inadequate.

The reasons for water scarcity are manifold. 

One reason is the growth in world population. To make matters worse, water consumption is increasing disproportionately to population growth. In the 20th century, water use was growing more than twice the rate of the population increase. Specifically, water withdrawals are predicted to increase by 50 per cent by 2025 in developing countries and 18 per cent in developed countries.

In addition, in some areas there is an over-exploitation of groundwater. Due to the expanding human population, competition for water is growing such that many of the world’s major aquifers are becoming depleted. 

Furthermore, the expansion of agricultural and industrial usage of water leads to water scarcity in some areas. 

Water pollution is another issue. And, of course, climate change can also contribute to water scarcity. Rising temperatures will increase evaporation and lead to increases in precipitation, with regional variations in rainfall. 

Because the causes are varied, so are the opportunities for improvement. 

Farmers will have to strive to increase productivity to meet growing demands for food, while industry and cities find ways to use water more efficientlyReservoirs and pipelines are needed to address the temporal and spatial variations. Desalination, the process that removes mineral components from saline water, can also help. And, of course, fighting climate change is a crucial point. 

So is my friend right when she decided to save water? 

The question can only be answered by knowing the local situation. 

In Germany, water resources are judged as sufficient since only approximately 24 per cent of available resources are used. But although Germany is rich in water, some regions lack water. Water shortages occur regularly in regions with unfavourable water balance, and this is particularly in the state of Brandenburg (which surrounds Berlin). 

Saving water could make even more sense in the future. “Climate change is projected to decrease groundwater levels by the end of the century, in particular under a high-end scenario of climate change,” writes Climate Change Post, a news site on Europe’s changing climate. And: “Under a low-end and moderate scenario of climate change, the impacts of climate change on groundwater levels are small. The tendency of declining groundwater levels is more clearly in the North and the East compared to the South, which emphasizes the already existing trends and patterns.” 

It seems my friend is doing a good job of saving water. 


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