We all live on planet earth, not planet water. Although the earth looks like a blue marble from space, water is a very thin coat over the earth. Even our oceans, which seem deep from the surface, are very thin compared to the globe. Furthermore, of all the water on the planet only 1% of it is fresh. And of that fresh water, only a small fraction is available for human consumption, as most is locked in glaciers.
Clearly, water is unevenly distributed across the globe, creating locations of extreme abundance and deficit. For example, the Great Lakes contain approximately 20% of all the surface fresh water on the planet, whereas a White Desert in Egypt receives less than one inch of rain per year. The inequity of water distribution across the globe is an obvious driver of water scarcity. But there are other drivers, and most water scientists will agree to two general types of water scarcity that human populations face.
One is a physical scarcity. This is where the demand for water has exceeded its supply. In this definition, there may be lots of water, just not enough to meet the demand. Typical solutions associated with resource scarcity are to either reduce the demands (through efficiency and/or changing the uses) or find new water supplies (drill wells to aquifers, dam rivers for storage). To elucidate this idea of resource scarcity, think of a city that has grown alongside a river. At first the river supplies all the needs of a small city. But rivers do not grow with population, and as the population and economies grow, they start to demand more water than the river can supply. So people start building reservoirs and seek other more distant sources of water – reaching ever further up the landscape.
The second type of scarcity, termed economic scarcity, occurs where water resources are high, but the management, governance or institutional know-how is not able to deliver the resource to the population. In this case, a scarcity of water is created if the city does not have the technology to clean the water, the governance to stop pollution, or the capital to build and maintain an appropriate pipe network to distribute the water. This is typified in many sub-Sahara African nations and in parts of India.
It is simple to pick up a newspaper today and see that cities around the globe are all facing both resource and economic scarcity. Modern capital cities across the globe are facing severe water scarcity. Beijing, China is well below the United Nations water scarcity index, and has less water per capita than cities like Cairo, Dubai, and Kuwait City. Sydney, Australia has been living with severe drought for over a decade and has implemented deep restrictions on water use. Sao Paolo, Brazil, a metropolis of over 20 million people has been rationing water to three days a week.
Cities of California are now facing a similar crises as many of our capital cities across the globe. And California is not that different from the rest of the United States in terms of its water withdrawal. According to the US Geological Survey, in 2010 90% of USA water withdrawals were for irrigation, energy and cities (public water supply). With energy about 45%, irrigation about 32% and cities taking about 12% of all water withdrawals.
There has been a lot written about the relationship between urban and rural needs of water, and what sector should reduce their demands. But the reality is that water needs to be managed as a comprehensive whole. The water on earth is all we have, we are not getting any more of it, and it is all the same water, the very same water that the dinosaurs lived with, the same water our ancestors drank and washed with, and will be the same water that all future generations must live with. The issue is not whether California cities should cut 20% of their water or agriculture should cut 60% of their water. The issue is that we need to manage all the water as if it is the precious life supporting gift that it is. Every person, every industry, and every state/city should be aware of its water footprint, and act responsibly.
Here I offer a few simple principles to assist in acting responsibly:
- Our industries can discharge less toxic stuff into our waterways. Nothing is easier to remove from water than the contaminant that is not there. This alone would directly improve the health and reduce water scarcity for millions of people.
- Agriculture can grow the right crop in the right place at the right time. There is no good reason to grow water loving crops such as rice in the desert.
- The energy sector can shift from thermos combustion to renewables. It takes 30,000 gallons of water to produce 1 megawatt hour of electricity from coal combustion vs less than 5,000 gallons of water for solar and virtually none for wind to produce the same amount of electricity. Shifting to renewables such as wind and solar is the crown jewel of lower greenhouse gases, lower water withdrawals and lower water toxicity.
- Cities can measure, value and conserve water at every use.
- People can educate themselves about the water cycle, change their relationship with water, and respect the natural ecologies that provide the water.
These are simple principles that we can all strive for in our professional and personal lives. It is worth being reminded that water is not the problem, the management of water is. It is the stuff we put in the water, the way we allocate its uses, and humanities relationship with water that generally under values its worth. Even urban flooding is not a water problem, but rather the result of short-sighted engineering or unrestrained growth.
This calls for a paradigm shift of both behavior and use of technology. And there is hope. Technology can assist us in the management and allocation of water, by better accounting for our water footprint. The trend of smart meters allow utilities to price water based on real-time usage patterns and therefore shift the behavior and time of use. Second, technologies that first prevent the contamination of water and removes toxicities once contaminated are in all phases of development. And third, ecological sensors are being deployed that will inform us of the water cycle, making so that the resource can be properly allocated, priced and treated.
California is getting a lot of attention, but we all need to pay attention to our own water footprint. The people in Sao Paolo, Beijing and New Delhi all once had reliable water 24 hours a day. Today, they don’t. It will take action from all of us to change our relationship with water and make sure more cities, and fewer people suffer the indignities and health impacts of water scarcity.