Every time we turn on the tap, we expect water to come out. However, our finite water supply is spluttering around the world. The problem of insufficient water already affects an estimated two billion people for at least one month of every year, across every continent – and it is growing particularly acute in cities as our urban population grows. In theory, we can source more water from any one of four big water taps:
In many places, water stress is caused by the lack of rainfall and the changes in climate that exacerbate droughts. Instead, some cities are turning to groundwater as freshwater supplies dry up in these local catchment areas. Underground aquifers have long served as a backup, storing around thirty percent of the planet’s entire freshwater. India is a starkest example as it is more dependent on water pumped from aquifers than any other nation. A study led by Tom Gleeson at the University of Victoria in B.C. concluded that only six percent of the groundwater contained less than two kilometres below the Earth’s landmass is renewable within a human lifetime. We are depleting water basins faster than they can recover. Critical groundwater resources are also compromised in some areas by soil pollution from pesticides and other contaminants, making these existing reserves unfit for human consumption.
Our aquifer tap is losing its capacity, drained and contaminated.
Despite the rainy climate, the U.K. imports over two-thirds of its water (according to Institute of Civil Engineers) – including from places with acute water shortages. Water is unwittingly imported to the U.K. and many other places with high per capita consumption in the form of items with a hefty amount of ‘embedded water’ or water required to create them. For example, growing cotton is a thirsty business with 2,500 litres of water needed for the average t-shirt and 10,000 litres in a pair of jeans. (For comparison, the average person needs 5 litres of water to drink daily and survive in a moderate climate.) Water is more obviously imported by cities in tankers and pipelines, transferred interstate and internationally. The fundamental problem with most of these formalised water imports is that the people who benefit do not have to pay the enormous costs of the transfers that are hidden in subsidies and taxes. Consequently, these individuals can afford to use even more water because the real cost is borne by elsewhere.
Our import tap often hides the full price of its water supply to users, but the cost of depleting the supplying basins is there regardless.
Seawater desalination currently provides around one percent of the world’s drinking water, but it is expensive and no major technology breakthroughs are expected over the next few years that would dramatically lower the cost or improve its efficiency. On the environmental front, desalination takes a toll on ocean biodiversity as microbial life and larvae are destroyed during the process. The very salty residue left over from desalination must also be disposed of properly as localised coastal areas cannot absorb tons of concentrated saltwater sludge. Solar-powered desalination is in its infancy and so most of the existing plants burn fossil fuels for their power. However, the real issue with the potential deployment of large-scale desalination technology is that it is, what economists call would, a ‘moral hazard’. We are taking unacceptable levels of risk by believing we will be protected from the consequences downstream. The moral hazard of our belief that we will be able to turn brine into limitless freshwater is that we squander our existing water supplies now, trusting desalination in the future to supply us with as much freshwater as we will ever need.
Our desalination tap won’t turn on fast enough for our immediate requirements, and we cannot afford to wait.
Municipal water providers can do more to improve the supply of water, often significantly, by upgrading their infrastructure and reducing current leakage levels. For our part, we can do more to manage our supply of non-potable water. One of the biggest changes is to make use of ‘greywater’, the relatively clean waste water from baths, sinks, washing machines, and other kitchen appliances. Currently we use drinking water for a host of things other than drinking. Some of this potable water becomes greywater that we pour down the drain after single use, to be thoroughly contaminated by mixing with toilet-based water. We do not have to pour away up to half our usable water supply. A simple recycling system runs the greywater through a filtration system located in our home or on site at work, and sends the recycled water back to supply non-potable uses, such as flushing toilets or watering plants.
Our greywater tap is hardly used, and yet it is one of the most cost effective and efficient ways of increasing our supply of water.
Turning on all the taps will improve the supply, but we cannot solve the issue of water scarcity from the supply side only. We will need to modify our current behaviour and reduce our demand in the first place, to recognise water for what it is – a precious and finite commodity.