Water
We probably don’t think about it every day, but without water there would be no life on earth. In space exploration, it’s the first question: is there water? Because where there is water, there is life. But just how important is in? If we humans don’t drink a certain amount every day, we die of dehydration.
If you forget to water a plant, it will sooner or later witter and die. Water is essentially the source of our existence. And yet we are not consciously occupied with its consumption day in, day out. For this blog I looked into how important water is in our daily lives.
Blue and green
We distinguish between blue and green water. Blue is the kind you can see and touch. It’s found in the sea, in rivers, in lakes, and deep underground. When you turn on the tap, blue water comes out. When a farmer irrigates his field with a hose, he’s using blue water. It can run out — if you pump too much of it from the ground, the level drops lower and lower, and one day it’s gone.
Green is the water you cannot see. It’s hidden in the soil beneath trees and grass, and in the leaves of plants themselves. A tree absorbs that water through its roots and slowly breathes it back into the air — like a kind of invisible respiration. That water rises, becomes a little cloud, and falls somewhere else as rain.
The problem is that we are removing vast numbers of trees and plants — for farmland, for cities, for animal feed. As a result, green water disappears. There is less “breathing”, fewer clouds, and therefore less rain over land. Some parts of the earth are becoming increasingly dry — not because the climate is changing, but because we have removed the ‘machines’ that make rain. That metaphor, in which I refer to trees as rain-making machines, deserves further explanation.
Rain machine
A large tree pumps hundreds of litres of water per day upward from the ground, through its roots and trunk, to its leaves. There, the water evaporates into the air. We call this transpiration — essentially sweating, but in a tree. All that evaporated water from millions of trees rises together, cools high in the atmosphere, and forms clouds. Those clouds move inland with the wind — and eventually fall as rain. Researchers call this the flying river: an invisible stream of moisture travelling through the air, thousands of kilometres.
The Amazon rainforest, for example, pumps so much water into the air that it generates its own rain — and the rain far beyond its borders, deep into South America. Cut down that forest, and not only the forest itself dries out, but also the farmland hundreds of kilometres away. And this applies closer to home too.
European forests and grasslands contribute to the moisture levels of the interior. The more farmland there is without trees or shrubs, the less moisture enters the air, and the hotter and drier the summer climate becomes. The dry summers we have experienced in the Netherlands in recent years are partly connected to this.
Water use at home
As a father, I try to convince my children not to shower for longer than five minutes. And that after using the toilet, they should press the small flush button rather than the large one. I also collect rainwater to top up our pond and water the plants.
By being mindful of our water use, our household consumes around one hundred cubic metres of water per year. That works out to 68.5 litres per person per day. The Dutch average, incidentally, is 120 litres per person per day. But that is unfortunately only the direct water use for tap, shower and toilet.
The hidden litres
When I add the indirect water use — the water consumed in producing our food, our clothing and the products we buy — the figure comes to around 3,300 litres per person per day for the average Dutch person. That is more than one million litres of water per person per year, for consumption alone.
I have to honestly admit that this large number comes as quite a shock. We are all aware, some more than others, of our direct water use. But that this accounts for barely four percent of our total water consumption — that I did not expect.
What can you do?
The largest share of indirect water is found in our food. This is followed by clothing (growing cotton), energy (cooling towers at power stations), transport (refining oil into petrol) and flying (refining oil into kerosene).
Food
Food is the factor that carries the most weight. A quarter of the total water footprint of an average Dutch person goes towards meat production — around 1,300 litres per day. Those who eat a plant-based diet use only 250 litres for this. Over the course of a year, that difference alone amounts to over 850,000 litres.
Clothing
Clothing is the second major factor. A single new T-shirt and pair of jeans already equals 9,500 litres of water. Buying secondhand saves virtually all the water that would otherwise be needed to produce new clothing. It also helps, of course, to keep your clothes for a long time, so you don’t need to buy new items frequently.
Energy and transport
Energy and transport are real but small compared to food. Swapping your petrol car for a hybrid or fully electric model does make a meaningful difference, however. So does reducing the number of short flights by choosing the train instead.
In short, for anyone looking to reduce their total water consumption, there are more than enough opportunities. The biggest gain doesn’t come from a shorter shower. It’s on your plate.