From Fresh Water

Transcription

At birth, our bodies are roughly 75% water. We remain mostly water for the rest of our lives. We cannot survive even a week without fresh water. There's no life without it for ecosystems, societies, and individuals. So, how much usable water is there on Earth? Most of the water on Earth is ocean, a salty 97.5%, to be precise, and the remaining 2.5% is fresh water. That little sliver of liquid sustains human life on Earth, it literally holds up civilizations. 2.5% is a small proportion to be sure, and even that is broken down into smaller parts: surface water, water in ice caps and polar regions, and ground water. First, surface water. All the liquid water above ground is surface water and it is a tiny blip of an amount. 0.3% of all fresh water is surface water. It may seem counterintuitive, but it accounts for little streams all over the planet. All rivers, including the Nile, the Jordan, and the Mississippi, and lakes, large to small, like Victoria, the Great Lakes, and Baikal. Second, ice caps and polar regions freeze up to 70% of the planet's fresh water. This water is significant, but it isn't available for human use in a regular way. Finally, nearly 30% of all water on Earth is ground water. As the name suggests, that's water in the ground. It can rest still and deep in huge caverns, or it can snuggle in the little crevices of rock and pebble. The upshot - thank goodness for ground water! It's invisible to us, but it is much more plentiful than surface water. It is much more reliable and easier to obtain than frozen water. Without ground water, our societies would be parched. So, how are we using that water? As a result of industrialization and population growth, demand for fresh water skyrocketed in the last century. Where is all that water going? First, we have to remember that fresh water is a global concern, but it is always local. Context matters. The Sahara is not Seattle. Still, some general information can help us get a handle on major trends. Who consumes the most fresh water? And, what sectors consume the most fresh water? First, who. Well, the United States consumes the most water per capita of any country in the entire world, followed by parts of Europe and large industrializing nations like China. But, this doesn't tell us what water is being used for. So let's look at it another way. If we ask what kinds of uses water is going towards, we see a different picture. Agriculture accounts for roughly 70% of global fresh water consumption. Again, remember the numbers vary by region, but still, it's a staggering amount. And, this makes a certain kind of sense: we need to eat, we need water to grow food; the bigger the population, the more food we need; and, the wealthier we get, the more meat we eat, and the more water is required to produce our food. Furthermore, 22% of all fresh water worldwide goes to industrial uses. This includes the production of electricity, the extraction of fossil fuels, and the manufacturing of all manner of goods, from microchips, to paper, to blimps. 70% to agriculture, 22% to industrial uses, what's left? 8% All those domestic uses - cooking, cleaning, bathing, drinking - it's a drop in the bucket of overall water use.