May 2009
HGS Bulletin
Peak Water?
The Limits of a Resource
Michael F. Forlenza, P.G.
HGS Editor
We never know the worth of water till the well is dry.
~Thomas Fuller, Gnomologia, 1732
When you turn on the faucet at your kitchen sink what do you expect to happen? You expect to get an unlimited supply of fresh potable water to use as you choose in your daily activities such as cooking, cleaning, drinking, flushing, and watering. In most of the developed world, this availability is hardly considered. But just where does that water come from and is it really unlimited or is the earth headed for a crisis?
Water is the ultimate renewable resource. It falls from the sky and a vast reservoir covers 70 percent of the globe. There is no less water today than there was 100 years ago, 1000 years ago, or even a million years ago. Water cycles through the biosphere in a matter of months or years. Surely there is no shortage of water. Yet, each week the media reports on another region in the United States or the world where insufficient water is causing economic hardships, human and ecological suffering, or conflict.
It turns out, that for a large part of the world, there is a shortage of usable, fresh, clean water. Whether due to climate change, poor resource management, over population, reckless use, or willful neglect, more than one billion people do not have access to an adequate supply of potable water and more than 2.5 billion do not have water for basic sanitary needs. Does this scarcity mark the limit of the resource? If water is the new oil, have we reached "Peak Water?"
Reaching the Limits
Approximately 97.5 percent of all the water on Earth is salty or polluted and unsuitable for human use. Of the remaining 2.5 percent, nearly 70 percent is frozen in the ice caps of Greenland and Antarctica. Large amounts of the unfrozen fresh water are found in soil moisture, trapped in deep water-bearing formations, or present as atmospheric water vapor. Only about one percent of the world’s fresh water, less than 0.01 percent of all of the world’s water, is available for direct human use in lakes, rivers, reservoirs, and easily accessible aquifers.
Like oil, water is not equitably distributed, respectful of political boundaries, or found in abundance where the demand is greatest. Just as some nations have great oil resources and others do not, so it is with water. About 50 percent of the world's fresh water lies in just a half-dozen lucky countries led by Russia and Brazil. In the last one hundred years, worldwide demand for fresh water has increased six-fold – twice the rate of population growth. This has created a fierce competition for this fluid treasure.
The ultimate source of all available fresh water is precipitation that falls on the continents. This amount is estimated be approximately 40,000 to 50,000 cubic kilometers per year. With annual population increases of about 85 million per year, the availability of fresh water per person is diminishing rapidly. And, this assumes that the amount of continental rainfall remains constant despite evidence that climatic shifts may be altering long-term precipitation patterns.
Agricultural uses put tremendous stress on available fresh water resources. Approximately 70 percent of all fresh water is used for agricultural purposes worldwide. Largely arid Pakistan uses 97 percent of its fresh water for agriculture, and China, with 20 percent of the world's population but only 7 percent of its water, uses 87 percent of its fresh water to irrigate crops.
Globally, many regions are facing water crises. A few of these are:
Australia. Australia is the most arid continent after Antarctica. Even with a population less than one-tenth of the United States, water resources are stretched to the breaking point. The worst drought in history is ravaging the nation. Rainfall has declined to 25 percent of the long-term average and is projected to plummet another 40 percent by 2050. Every major city in Australia has severe water restrictions in place and agriculture is crippled. In 2008, huge unchecked wildfires swept across the desiccated landscape.
Middle East. A 2008 report by the World Bank estimates that the amount of water available per person in this arid and politically volatile region will halve by 2050.
Africa. Desertification has allowed the Sahara to claim large stretches of the surrounding countries. Lake Chad, one of the largest lakes in the world when first surveyed in 1823,