August 19, 2016

Water Our Resource

WATER is essential to human survival and well-being and important to many sectors of the economy. However, resources are irregularly distributed in space and time, and they are thus under pressure placed by human activity. Nearly 97 per cent of the world’s water supply by volume is held in the oceans. The other large reserves are groundwater (4 per cent) and icecaps and glaciers (2 per cent), with all other water bodies together accounting for a fraction of 1 per cent. Residence times vary from several thousand years in the oceans to a few days in the atmosphere.
Although public awareness of the need to better manage and protect water has grown over the last decade, economic criteria and political considerations still tend to drive water policy at all levels. Humans need water for drinking, sanitation, agriculture, and industry, and contaminated water can spread illnesses and disease vectors. So, clean water is both an environmental and a public health issue. Meeting a continuous and ever increasing demand for water requires efforts to compensate for natural variability, and to improve the quality and quantity available.
The world’s water exists naturally in different forms and locations: in the air, on the surface, below the ground, and in the oceans. Freshwater accounts for only some 6 per cent of the world’s water supply, but is essential for human uses such as drinking, agriculture, manufacturing, and sanitation. Two-thirds of global freshwater is found underground. If you dig deeply enough anywhere on Earth, you will hit water. Some people picture groundwater as an underground river or lake, but in reality it is rarely a distinct water body (large caves in limestone aquifers are one exception). Rather, groundwater typically fills very small spaces (pores) within rocks and between sediment grains, thus I have learned.
Earth’s water resources, including rivers, lakes, oceans, and underground aquifers, are under stress in many regions. Millions of people worldwide depend on groundwater stocks, which they draw from aquifers— permeable geologic formations through which water flows easily. Very transmissive geologic formations are desirable because water levels in wells decline little even when pumping rates are high, so the wells do not need to be drilled as deeply as in less transmissive formations and the energy costs of lifting water to the surface are not excessive. Under natural conditions many aquifers are artesian: the water they hold is under pressure, so water will flow to the surface from a well without pumping, thus I have learned.
River flows can vary greatly from one season to the next and from one climatic region to another. Rivers contain a relatively small share of fresh water, but the flux of water down rivers is a large part of the global hydrologic cycle and they are centrally important in shaping landscapes. Their flow erodes solid sediment and carries it toward the sea, along with dissolved minerals. These processes shape land into valleys and ridges and deposit thick layers of sediment in flood plains. Over geologic time the erosion caused by rivers balances the uplift driven by plate tectonics. Much of Earth’s freshwater flow passes through several of the planet’s largest rivers: the Amazon carries 15 per cent of total river flow on Earth, the Congo carries 3.5 per cent, and rivers that flow into the Arctic Ocean carry 8 percent. The average residence time of water in rivers is less than a year, thus I have learned.
Overall, water shortages severely reduce biodiversity in both aquatic and terrestrial ecosystems, while water pollution facilitates the spread of serious human diseases and diminishes water quality
Underground water is often overexploited and polluted. Unmanaged systems are likely to be most vulnerable to climate change challenges, existing water resources management practices by adding additional uncertainty and integrated water resources management will enhance the potential for adaptation to change, thus I have learned.
Really, water resources are under major stress around the world. Rivers, lakes, and underground aquifers supply fresh water for irrigation, drinking, and sanitation, while the oceans provide habitat for a large share of the planet’s food supply. Today, however, expansion of agriculture, damming, diversion, over-use, and pollution threaten these irreplaceable resources in many parts of the globe. Providing safe drinking water for the more than one billion people who currently lack it is one of the greatest public health challenges facing national governments today. In many developing countries, safe water, free of pathogens and other contaminants, is unavailable to much of the population, and water contamination remains a concern even for developed countries with good water supplies and advanced treatment systems. And over-development, especially in coastal regions and areas with strained water supplies, is leading many regions to seek water from more and more distant sources.
Realizing that the water covers about three-quarters of Earth’s surface is a necessary element for life. During their constant cycling between land, the oceans, and the atmosphere, water molecules pass repeatedly through solid, liquid, and gaseous phases (ice, liquid water, and water vapour), but the total supply remains fairly constant. A water molecule can travel to many parts of the globe as it cycles, thus I have learned.
Even though the temperature of the water vapour may not increase when it evaporates from liquid water, this vapour now contains more energy, which is referred to as latent heat. Atmospheric circulation moves this latent heat around Earth, and when water vapour condenses and produces rain, the latent heat is released. Water vapour redistributes energy from the sun around the globe through atmospheric circulation. This happens because water absorbs a lot of energy when it changes its state from liquid to gas.
Studies show that the land and water resources and the way they are used are central to the challenge of improving food security across the world. Demographic pressures, climate change, and the increased competition for land and water are likely to increase vulnerability to food insecurity particularly Africa and Asia. The challenge of providing sufficient food for everyone worldwide has never been greater.
The world’s population continues to rise. Today’s population of around 7 billion is expected to increase to about 9 billion by 2050 (United Nations, 2009).  By this time, another one billion tonnes of cereals and 200 million extra tonnes of livestock products will need to be produced every year (Bruinsma, 2009). The imperative for such agricultural growth is strongest in developing countries, where the challenge is not just to produce food but to ensure that families have access that will bring them food security. Today almost 1 billion people are undernourished, particularly in Sub-Saharan Africa (239 million) and Asia (578 million). In developing countries, even if agricultural production doubles by 2050, one person in twenty still risks being undernourished – equivalent to 370 million hungry people, most of whom will again be in Africa and Asia. Such growth would imply agriculture remaining an engine of growth, vital to economic development, environmental services and central to rural poverty reduction. For nutrition to improve and for food insecurity and undernourishment to recede, future agricultural production will have to rise faster than population growth. This will have to occur largely on existing agricultural land. Improvements will thus have to come from sustainable intensification that makes effective use of land and water resources as well as not causing them harm. The policies, practices and technologies needed to boost production and strengthen food security have long been discussed. Institutional mechanisms, the development of trade and markets and the financial facilities needed to raise productivity in a sustainable way have been negotiated at the international level. At national level, measures to raise output and strengthen food security are being put in place, including investment in pro-poor, market-friendly policies, institutions and incentives, as well as the infrastructure and services needed to improve productivity. Yet the challenge still remains.
Of the freshwater which is not frozen, almost all is found below the surface as groundwater and generally of high quality. Groundwater is being withdrawn mostly to supply drinking water and support farming in dry climates.
Using water resources sustainably is challenging because of many factors involved including changes in climate, the natural variability of the resource, as well as pressures imposed by human activity.
Realize that “Our water resources are under pressure and more reliable information is still needed regarding the quality and quantity of available water, how this availability varies in time and from place to place and human activities affect the water cycle in many ways, which need to be understood and quantified to manage water resources responsibly and sustainably.”
Changes in climate are affecting water availability, pollution, water diversions and uncertainties about the abundance of water are threatening economic growth, environment, and health, to augment water supply, traditional techniques – such as rainwater collection – are now being supplemented by newer technologies like desalination and water reuse and political support is needed to improve information collection that can in turn enable better decision making about the management and use of water.
Estimates from river outflows indicate that some 17 billion tons of material are transported into the oceans each year, of which about 80 percent is particulate and 20 percent is dissolved. On average, Earth’s surface weathers at a rate of about 0.5 millimeter per year. Actual rates may be much higher at specific locations and may have been accelerated by human activities, such as emissions from fossil fuel combustion that make rain and snowfall more acidic, thus I have learned. May all beings be free from fresh water shortage in the years to come!!! May adequate fresh drinking water be in your easy access!!! May God bless you always!!!


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