I was born in a country with the second largest reserves of fresh water. I can say, I am happy. Water is a luxury commodity. Most countries have a deficiency of drinking water and according to damage our environment, the deficiency will rise. Most at risk are developing countries.
Rapidly growing populations and migration to urban areas in developing countries has resulted in a vital need for the establishment of centralized water systems to disseminate potable water to residents. Protected source water and modern, well-maintained drinking water treatment plants can provide water adequate for human consumption. However, ageing, stressed or poorly maintained distribution systems can cause the quality of piped drinking water to deteriorate below acceptable levels and pose serious health risks.
The declining availability of water supplies is one of the most important environmental issues facing various countries at the present time. It has been estimated that nearly two-thirds of nations worldwide will experience water stress by the year 2025 (United Nations Environment Programme 2002). Climate change, affluence and population growth have resulted in vast requirements of water for use in domestic, industrial and agricultural settings.
The water cycle (shown in the following figure) is a delicate balance of precipitation, evaporation, and all of the steps in between. Warmer temperatures increase the rate of evaporation of water into the atmosphere, in effect increasing the atmosphere’s capacity to “hold” water. Increased evaporation may dry out some areas and fall as excess precipitation on other areas.
Changes in the amount of rain falling during storms provide evidence that the water cycle is already changing. Over the past 50 years, the amount of rain falling during the most intense 1% of storms increased by almost 20%. Warming winter temperatures cause more precipitation to fall as rain rather than snow. Furthermore, rising temperatures cause snow to begin melting earlier in the year. This alters the timing of streamflow in rivers that have their sources in mountainous areas.
As temperatures rise, people and animals need more water to maintain their health and thrive. Many important economic activities, like producing energy at power plants, raising livestock, and growing food crops, also require water. The amount of water available for these activities may be reduced as Earth warms, and if competition for water resources increases. [
Fresh water is crucial to human society – not just for drinking, but also for farming, washing and many other activities. It is expected to become increasingly scarce in the future, and this is partly due to climate change.
Understanding the problem of fresh water scarcity begins by considering the distribution of water on the planet. Approximately 98% of our water is salty and only 2% is fresh. Of that 2%, almost 70% is snow and ice, 30% is groundwater, less than 0.5% is surface water (lakes, rivers, etc) and less than 0.05% is in the atmosphere. Climate change has several effects on these proportions on a global scale. The main one is that warming causes polar ice to melt into the sea, which turns fresh water into sea water, although this has little direct effect on water supply.