In the past few years, we’ve made great strides in energy-efficiency. With climate change entering the mainstream, people are starting to drive less, carpool more, and take out their old bicycles. It has helped us to save money, spur our economy, protect our forests, and reduce our dependence on oil.

Despite our progress in energy-efficiency, this is no time to rest on our laurels. It’s actually a cause for great concern. Subtly but surely, sustainable living is being reduced to nothing more than the single issue of reducing carbon emissions. Our society talks about carbon dioxide as if greenhouse gas management is all that there is to caring for the earth. Environmental protection, however, means so much more than not burning gasoline.

One vital issue that has been sorely neglected is water conservation. Very few people realize that water, much like gasoline, is a scarce resource that’s being depleted at unprecedented rates. In fact, water production may someday peak, just as oil will. As of today, the world has managed to increase water production to temporarily meet rising demands. In the future, however, water supply may hit an apex and then slowly decline. The world has already seen how declining oil reserves can hurt economies and increase political instability. But the situation will be far worse with water, since without this essential resource, drought and famine can devastate entire civilizations.

The situation already looks dire. In America, about one quarter of all irrigated land relies on the Ogalla aquifer. The precious groundwater from this aquifer is vital to agriculture in the Midwest: we use it to raise livestock and grow wheat, corn, and soybeans. In the last two decades, groundwater levels have declined at alarming rates, with the water table declining by over 30 feet in some areas. New wells must be drilled ever deeper to extract groundwater that is quickly running out.

Water shortage is a looming crisis for the rest of the world, too. Even though India is not a dry country, it struggles to supply enough water for drinking and agriculture for its population of over one billion. In more arid regions, prolonged drought can force communities to ration water. In the last few years, Australia has been forced to undergo strict water rationing to avoid permanently damaging the Murray-Darling basin. Farms in this region have been forced to shut down, and local communities have even been forced to limit showering in efforts to conserve water.

Global water crises are only getting worse. Consumer culture is putting an ever greater strain on the earth’s limited supply by increasing unnecessary industrial use of water. Global warming also threatens to change rainfall patterns, which will make the water situation more unstable. If climate change occurs, moist areas are likely to experience heavier rainfall, which will lead to flash floods. Dry areas, however, are prone to becoming even drier, which may lead to deserts.

As water supplies continue to shrink, less water will be available for agriculture. This food scarcity will result in a prolonged spike in food prices. This could be catastrophic for the poor, who spend much of their income on food alone. Climate change, combined with underground water depletion, could devastate our agriculture and harm our economy. Unfortunately, water shortage is an urgent environmental crisis that the public is failing to grasp.

To appreciate the importance of water, it helps to understand the water cycle. It all begins when the sun heats saltwater from the ocean. As water evaporates, it forms water vapor which can condense to form clouds. If these clouds move over land, water droplets can precipitate as rain, which can fall on vegetation or the bare ground. Rain that hits vegetation provides the water for photosynthesis, a biological reaction that helps plants grow. Water that hits bare ground can run-off the surface to pool in larger bodies of water, which helps forms streams and rivers.

Much of the water that falls on the ground surface will evaporate once again to reform water vapor. However, some of the rain water can also infiltrate into the soil, where it can collect as groundwater. In the diagram, the water table is the surface at which all sediment beneath it is completely filled with water. The height of the water table can increase or decrease, depending on factors like the rate of rainfall. Groundwater doesn’t always stay underground permanently. It can naturally resurface at lower elevations to form springs on the surface, or it can be extracted by man-made wells.

All of these processes — evaporation, condensation, precipitation, and infiltration — are occurring constantly to form the water cycle.

Although the earth has plenty of water, most of it is not fit to drink (the water is not potable). Most of the earth’s water is saltwater, which cannot be used unless it is desalinated by expensive, energy-intensive processes. Less than 3% of the earth’s remaining water is freshwater, but unfortunately, even these sources are often undrinkable. Most freshwater is frozen in glaciers; of the remaining freshwater, much of it has been tainted by pollution. In the past, rivers were often contaminated with biological pollution including human feces, which transmitted disease such as typhoid and cholera. Today, however, modern pollutants involve chemicals like mercury, lead, and pesticides. Pollution can make it difficult, if not impossible, to safely purify water for drinking.

There are many methods to collect water. One method is to catch rain as it falls. Using rain catchment systems (1), it’s possible to store rain for drinking during dry seasons. In the same fashion, farmland in moist areas might rely entirely on rain instead of using irrigation to grow their crops.

Besides rainfall, we also turn to rivers and springs for water. Unfortunately, a civilization’s demand for water usually exceeds what’s available on the surface. That’s because people are generally terrible at conservation. Besides satisfying our basic needs for food, drink, and hygiene, we like to indulge in water-intensive luxuries. Modern man enjoys living in deserts, wasting food, watering lawns, taking long baths, and owning private swimming pools. Given our insatiable appetite, surface water just won’t cut it.

To deal with this water shortage, we often build underground wells that tap into the ground water. There is about sixty times more groundwater than there is surface water, so in the short run, this vastly improves our supply. Our wells extract water from underground aquifers, which have collected infiltrated rainwater through the centuries. Because these wells pull from a large reservoir, they can supply far more water than is normally replenished through rainfall.

But cheap water is a mixed blessing. Whenever a scarce resource appears to be virtually unlimited, we tend to waste it with devastating consequences. In only a few years, it’s possible to squander groundwater that took centuries to deposit. Usually this groundwater is not allowed to replenish naturally, which results in shrinking reservoirs each year. This can result in the formation of deserts and massive water shortages in the future.

This environmental catastrophe can lead to human catastrophes like economic collapse and even water wars. What makes these crises so tragic is that they’re mostly preventable. Our planet has plenty of water for all if we chose to build a culture centered around sustainable development.

We must act conserve and we must start now. Time, along with our water supply, is quickly running out.

1. Here’s a video of a simple, off-grid rainwater barrel that’s worth checking out. Collecting rainwater is a great idea, mostly because it helps the average homeowner to appreciate the scarcity of water.
2. Photo credit in order: Schilling 2, CC BY-NC-ND. Kbh3rd, CC BY-SA.
   United States Geological Survey, public domain.
   US Geological Survey, slight modification to make words look clearer.
   National Department of Agriculture Rural Inforeach, PDF file.