Water stress occurs when the demand for water exceeds the available amount during a certain period or when poor quality restricts its use. A country is said to experience "water stress" when annual water supplies drop below 1,700 cubic meters per person. At levels between 1,700 and 1,000 cubic meters per person, periodic or limited water shortages can be expected. When annual water supplies drop below 1,000 cubic meters per person, the country faces water scarcity.
The world's population is growing at a rate of 80 million people each year. This means that each year we need to find a way to add about 64 billion cubic meters of water to the global water supply. The two fastest-growing areas are Africa and the Middle East. The Sub-Saharan African population is growing at a rate of 2.6% people a year, and in the Middle East it is growing at a rate of 2.2%. Africa is already one of the driest continents in the world, and with this constant change is facing water stress and water scarcity.
Increased Urbanization and Increased Consumption
For the first time in the history of mankind the number of those living in towns and cities exceeds those living in the countryside. Within a generation two thirds of the world's population will live in towns or cities. With regard to drinking water, this development increases the pressure on resources that are already in short supply. As for sanitation, the effect of this increasing urbanization is a greater concentration of domestic and industrial pollution and a greater risk of run-off and flooding due to soil impermeabilisation. For all of these reasons, it is highly possible that increased urbanization, if badly managed, will result in a water crisis.
Water is very often wasted despite the fact that water resources are often scarce and fragile. It is not uncommon for half the drinking water in the water supply system to be lost due to leakage, illegal connections to the water mains or a badly maintained water supply system. In addition, agricultural irrigation - which accounts for 60% of water consumption - is often carried out with no thought given whatsoever to water conservation. The largest user of water in every country is agriculture. Trying to farm in hot, arid countries is difficult, if not impossible at times. Agriculture uses 70% of the world's supply, with industry coming in second with 22% of global use, and only 8% used for domestic household purposes.
According to scientists, climate warming will lead to an increase in extreme climatic phenomena such as droughts and heatwaves, but also violent rainstorms and flooding, thereby increasing pressure on water resources in already arid areas.
Lack of sanitation
The lack of a wastewater treatment system leads to rivers becoming polluted. Such as in the Mediterranean region, where more than half the wastewater is released back into the environment untreated. Almost 60% of wastewater released back into the Caspian Sea has not been treated. These figures are taken from a 2006 UNDP (United Nations Environment Programme) report on the impact of wastewater which also notes that "a rising tide of sewage is threatening the health and wealth of far too many of the world's seas and oceans."
At present there are about 12,000 square kilometres of polluted fresh water in the world, and if trends are not slowed or reversed, the total will reach 18,000 sq km by 2050, nearly nine times the total amount currently used for irrigation.
(a) Economic growth and water demand
Population growth implies increased demand for agricultural products, and so increased demand for water. Agriculture is by far the greatest consumer of water, accounting for 70% of all water consumption (compared to 20% for industry and 10% for domestic use). Unless agricultural water use is optimized, water demand for agriculture worldwide would increase by 70 to 90% by 2050, even though a number of countries are already reaching the limits of their water resources. At the same time, there have been changes in lifestyles and eating habits in recent years due to economic growth, in particular an increase in the share of meat and dairy products consumed in emerging countries. The production of a kilo of wheat requires 800 to 4,000 litres of water, while a kilo of beef, takes 2,000 to 16,000 litres. It is estimated that the Chinese consumer who ate 20 kilos of meat in 1985 will eat over 50 kilos in 2009. This will mean an additional 390 km3 of water for China’s production. By comparison, in 2002, the consumption of meat per inhabitant was 76 kilos in Sweden and 125 kilos in the USA.
Meanwhile, energy demand is accelerating, with corresponding implications for water demand. Global energy demands are expected to grow by as much as 55% through 2030. China and India alone would account for about 45% of this increase. Electricity generation from hydropower is projected to increase at an average annual rate of 1.7% from 2004 to 2030 – an overall increase of 60%. Criticized for their heavy footprint on the environment and their tendency to displace large numbers of people, dams nevertheless seem, for many, to offer a solution, given diminishing fossil fuel supplies, the need to shift to cleaner energy sources and the potential use of added storage in adapting to the increased hydrologic variability and uncertainty due to climate change. The energy aspect is particularly true for developing countries, where the potential for hydropower is considerable.
(b) Water insecurity and water poverty
Water insecurity means not having access to sufficient, safe water. Despite efforts to improve supplies and sanitation ($30 billion is spent each year worldwide), there are 1.2 billion people without access to clean water, many of whom live in the 20 or so countries classified as “water scarce”. Typically in these countries the poor are the most water insecure, with few opportunities to escape from poverty and access the benefits pf economic development. The problems of water insecurity are related to:
· Availability –having a water supply and distribution network
· Access- freedom to use or income to buy water in a particular location
· Usage- entitlement to, and understanding of, water use and health issues
In the UK, a household is defined as suffering from water poverty if it spends more than three per cent of its income on water. Although UK law does not allow a household's supply to be cut off, rising prices and increased debt can have serious knock-on effects for consumers, affecting their ability to pay for other essentials such as food and fuel.