- The concept of water stress is relatively simple: Accordi ng to the World Business Council for Sustainable Develo pment, it applies to situations where there is not enough water for all uses, whether agricultural, industrial or dom estic. Defining thresholds for stress in terms of available water per capita is more complex, however, entailing ass umptions about water use and its efficiency. Nevertheles s, it has been proposed that when annual per capita rene wable freshwater availability is less than 1,700 cubic met ers, countries begin to experience periodic or regular wat er stress. Below 1,000 cubic meters, water scarcity begin s to hamper economic development and human health a nd well-being.
Population growth In 2000, the world population was 6.2 billion. The UN estimates that by 2050 there will be an additional 3.5 billion people with most of the growth in developing countri es that already suffer water stress. Thus, water demand will increase unless there are corresponding increases in water conservation and recycling of this vital resour ce. Increased affluence The rate of poverty alleviation is increasing especially within the two population gia nts of China and India. However, increasing affluence inevitably means more water consumption: from needing clean fresh water 24 hours a day, 7 days a week and b asic sanitation service, to demanding water for gardens and car washing, to wantin g jacuzzis or private swimming pools. Expansion of business activity Business activity ranging from industrialization to services such as tourism and ent ertainment continues to expand rapidly. This expansion requires increased water s ervices including both supply and sanitation, which can lead to more pressure on w ater resources and natural ecosystems.
Climate change Climate change could have significant impacts on water resources around the worl d because of the close connections between the climate and hydrologic cycle. Risi ng temperatures will increase evaporation and lead to increases in precipitation, th ough there will be regional variations in rainfall. Overall, the global supply of freshw ater will increase. Both droughts and floods may become more frequent in different regions at different times, and dramatic changes in snowfall and snowmelt are exp ected in mountainous areas. Higher temperatures will also affect water quality in w ays that are not well understood. Possible impacts include increased eutrophicatio n. Climate change could also mean an increase in demand for farm irrigation, gard en sprinklers, and perhaps even swimming pools. Rapid urbanization The trend towards urbanization is accelerating. Small private wells and septic tank s that work well in low-density communities are not feasible within high-density urb an areas. Urbanization requires significant investment in water infrastructure in ord er to deliver water to individuals and to process the concentrations of wastewater – both from individuals and from business. These polluted and contaminated waters must be treated or they pose unacceptable public health risks. In 60% of European cities with more than 100,000 people, groundwater is being us ed at a faster rate than it can be replenished. Even if some water remains available, it costs more and more to capture it.
Africa has the worst water problem in the whole world. Because of the drought and rapidly growing population, Africas water supply is going worse and worse. Also, Overgrazing the farm and burning field for place to grow plants are driving water shortage to more serious point. The scientists said that By 2020, tens or hundreds of millions of people in Afric a are projected to "be exposed to an inc rease of water stress" due to climate ch ange, and yields from crops could drop up to 50 per cent, the report said. The continent, already plagued by dec ades of desertification, faces even wors e challenges as the areas suitable for gr owing, the rainy seasons and crop yield s shrink. Also, because of the limited water sources, countries are making war to take it from other countries. Such situations make Africans to more rely on foreign Aid and worsen their life. Children drinking dirty water easily die from disease.
Unlike Africa, where the main reason for water shortage is Overgrazing and climate, china s water shortage came with the rapid urbanization. As population dramatically grew and industry also developed amazingly, factories using water as a resource increased as well. Therefore, clean water for people to drink became scarce. Also, the northern part of china is near to desert and it s size is increasing because of the drought around desert and shortage of water. Water shortage is creating new problems too, such as increased yellow dust wind created from upper part of China, Gobi desert. Further more, scarcity for clean water caused the water price to be raised suddenly and the poor people and people living in isolated area are not supplied with clean enough water to drink. contaminated water are often drunken by them and that is causing serious problem in China.
The Dust Bowl of the 1930s is usu ally known for being the period for severe drought across many states ; 1934, 1936 and 1939 were extre mely hot and dry years across the United States. Hot temperatures le d to the deaths of many people, liv estock and animals all over the Uni ted States. Temperatures of 100 °F (38 °C) to 105 °F (41 °C) or higher would be very common over the United Stat es; dust storms were also common ; many people residing in the Unite d States suffered. Worse, these dr oughts hit while the Great Depressi on was affecting economies, famili es and children over the United St ates.
Global warming is the increase in the average temperature of the Earth's near-sur face air and oceans since the mid-20th century and its projected continuation. This h as not happened since the late 1990s. Global surface temperature increased 0.74 ± 0.18 °C (1.33 ± 0.32 °F) between the start and the end of the 20th century. The Intergovernmental Panel on Climate Change (IPCC) concludes that most of th e observed temperature increase since the middle of the 20th century was caused b y increasing concentrations of greenhouse gases resulting from human activity such as fossil fuel burning and deforestation. The IPCC also concludes that variations in natural phenomena such as solar radiat ion and volcanoes produced most of the warming from pre-industrial times to 1950 a nd had a small cooling effect afterward. Climate model projections summarized in the latest IPCC report indicate that the gl obal surface temperature will probably rise a further 1.1 to 6.4 °C (2.0 to 11.5 °F) dur ing the twenty-first century.
The main reason for the temperature of earth to increase is CO 2. Carbon dioxide ca n keep heat more powerfully than any other kinds of gas. This is called Green Hous e Effect. There are lots of causes of increased Green House Gases emission. 1. Industrialization The more fossil fuel we use, the more CO2 produced. After 18 th centuries humans h ave developed industry dramatically and that development was possible because of the use of coal and oil. This is proved by many data showing the rapid increase of te mperature started from near 1700s. Because the industrializations speed is rising, T he emission of CO2 already have reached alert level. 2. Population growth. Populations growth not only brings the problem of industrialization but also the incre ased need for food. So, people are growing more and more plants and cows and tha t also cause the increase of green house gases like methane. Methane works just a s same as Carbon dioxide. 3. Solar Radiation. This takes the least part, but still cant ignore its effect. In fact, in the past solar radi ations only made earth to reach temperature like now.
Cloud feedback Warming is expected to change the distribution and type of clouds. Seen fr om below, clouds emit infrared radiation back to the surface, and so exert a warming effect; seen from above, clouds reflect sunlight and emit infrared ra diation to space, and so exert a cooling effect. Whether the net effect is war ming or cooling depends on details such as the type and altitude of the clou d. These details were poorly observed before the advent of satellite data an d are difficult to represent in climate models. Ice-albedo feedback Aerial photograph showing a section of sea ice. The lighter blue areas are melt ponds and the darkest areas are open water, both have a lower albedo than the white sea ice. The melting ice contributes to ice-albedo feedback. When ice melts, land or open water takes its place. Both land and open wat er are on average less reflective than ice and thus absorb more solar radiati on. This causes more warming, which in turn causes more melting, and this cycle continues.
Increasing Sea Level When the ice in poles melt, naturally, the sea level rises. It,may seem as nothing serious but gradually it creates big impact. In fact, small Islands near equator are already in the danger of being submerged by water. Then are evacuating their citizens to other countries around them. Extinction of animals. Because of the sudden (relatively) climate change in animals hebetate, susceptible animals started to disappear from the earth. Map showing the change in hebetate of animals around the world.
Pollution is the introduction of contaminants into an environm ent that causes instability, disorder, harm or discomfort to the ec osystem. Pollution can take the form of chemical substances, or energy, such as noise, heat, or light. Pollutants, the elements of pollutio n, can be foreign substances or energies, or naturally occurring; when naturally occurring, they are considered contaminants wh en they exceed natural levels. Pollution is often classed as point source or nonpoint source p ollution. Pollution became a popular issue after WW2, when the aftermath of atomic warfare and testing made evident the perils of radioactive fallout.
Air pollution is the release of chemicals and particulates into the atmosphere. Co mmon gaseous air pollutants include carbon monoxide, sulfur dioxide, chlorofluor ocarbons (CFCs) and nitrogen oxides produced by industry and motor vehicles. P hotochemical ozone and smog are created as nitrogen oxides and hydrocarbons r eact to sunlight. Particulate matter, or fine dust is characterized by their micromete r size PM 10 to PM 2.5. Water pollution, by the release of waste products and contaminants into surface runoff into river drainage systems, leaching into groundwater, liquid spills, wastew ater discharges, eutrophication and littering. Soil contamination occurs when chemicals are released by spill or underground leakage. Among the most significant soil contaminants are hydrocarbons, heavy metals, MTBE, herbicides, pesticides and chlorinated hydrocarbons. Radioactive contamination, resulting from 20th century activities in atomic physi cs, such as nuclear power generation and nuclear weapons research, manufactur e and deployment.
Air pollution comes from both natural and man made sources. Though globall y man made pollutants from combustion, construction, mining, agriculture an d warfare are increasingly significant in the air pollution equation. Motor vehicle emissions are one of the leading causes of air pollution.China, United States, Russia, Mexico, and Japan are the world leaders in air pollutio n emissions. Ordinary municipal landfills are the source of many chemical substances ent ering the soil environment (and often groundwater), emanating from the wide variety of refuse accepted, especially substances illegally discarded there, or from pre-1970 landfills that may have been subject to little control in the U.S. or EU. There have also been some unusual releases of polychlorinated dibenz odioxins, commonly called dioxins for simplicity, such as TCDD. Pollution can also be the consequence of a natural disaster. For example, hur ricanes often involve water contamination from sewage, and petrochemical s pills from ruptured boats or automobiles. Larger scale and environmental da mage is not uncommon when coastal oil rigs or refineries are involved. Some sources of pollution, such as nuclear power plants or oil tankers, can produc e widespread and potentially hazardous releases when accidents occur.
Adverse air quality can kill many organisms including humans. Ozone p ollution can cause respiratory disease, cardiovascular disease, throat inf lammation, chest pain, and congestion. Water pollution causes approximately 14,000 deaths per day, mostly du e to contamination of drinking water by untreated sewage in developing countries. An estimated 700 million Indians have no access to a proper t oilet, and 1,000 Indian children die of diarrheal sickness every day. Oil spills can cause skin irritations and rashes. Noise pollution induces hearing loss, high blood pressure, stress, and sleep disturbance. Mercury has been linked to developmental deficits in children and neurologic symptoms. Older people are majorly exposed to diseases induced by air pollution. Those with heart or lung disorders are under additional risk. Children an d infants are also at serious risk. Lead and other heavy metals have been shown to cause neurological p roblems. Chemical and radioactive substances can cause cancer and as well as birth defects.
Sulphur dioxide and nitrogen oxides can cause acid rain which lowers the pH valu e of soil. Nitrogen oxides are removed from the air by rain and fertilise land which can change the species composition of ecosystems. Soil can become infertile and unsuitable for plants. This will affect other organisms in t he food web. Smog and haze can reduce the amount of sunlight received by plants to carry out pho tosynthesis and leads to the production of tropospheric ozone which damages plants. Invasive species can out compete native species and reduce biodiversity. Invasive pl ants can contribute debris and biomolecules (allelopathy) that can alter soil and chemi cal compositions of an environment, often reducing native species competitiveness. Carbon dioxide emissions cause ocean acidification, the ongoing decrease in the p H of the Earth's oceans as CO 2 becomes dissolved. The emission of greenhouse gases leads to global warming which affects ecosystems in many ways.
International Since pollution crosses political boundaries international treaties have been made th rough the United Nations and its agencies to address international pollution issues. -Greenhouse gas emissions The Kyoto Protocol is an amendment to the United Nations Framework Convention on Climate Change (UNFCCC), an international treaty on global warming. It also rea ffirms sections of the UNFCCC. Countries which ratify this protocol commit to reduc e their emissions of carbon dioxide and five other greenhouse gases, or engage in e missions trading if they maintain or increase emissions of these gases. A total of 141 countries have ratified the agreement. Canada In Canada the regulation of pollution and its effects are monitored by a number of or ganizations depending on the nature of the pollution and its location. The three level s of government (Federal - Canada Wide; Provincial; and Municipal) equally share i n the responsibilities, and in the monitoring and correction of pollution.
United States The United States Environmental Protection Agency (EPA) established threshold st andards for air pollutants to protect human health on January 1, 1970. One of the ra tings chemicals are given is carcinogenicity. In addition to the classification "unknow n", designated levels range from non-carcinogen, to likely and known carcinogen. S ome scientists have said that the concentrations which most of these levels indicate are far too high and the exposure of people should be less. In 1999, the United Stat es EPA replaced the Pollution Standards Index (PSI) with the Air Quality Index (AQI ) to incorporate new PM2.5 and Ozone standards. China China's rapid industrialization has substantially increased pollution. China has som e relevant regulations: the 1979 Environmental Protection Law, which was largely m odeled on U.S. legislation. But the environment continues to deteriorate. Twelve ye ars after the law, only one Chinese city was making an effort to clean up its water di scharges. This indicates that China is about 30 years behind the U.S. schedule of e nvironmental regulation and 10 to 20 years behind Europe. In July 2007, it was rep orted that the World Bank reluctantly censored a report revealing that 750,000 peop le in China die every year as a result of pollution-related diseases. China's State En vironment Protection Agency and the Health Ministry asked the World Bank to cut t he calculations of premature deaths from the report fearing the revelation would pro voke "social unrest".
Pollution control is a term used in environmental management. It means the control of e missions and effluents into air, water or soil. Without pollution control, the waste product s from consumption, heating, agriculture, mining, manufacturing, transportation and othe r human activities, whether they accumulate or disperse, will degrade the environment. I n the hierarchy of controls, pollution prevention and waste minimization are more desira ble than pollution control. Pollution control devices Dust collection systems -Cyclones -Electrostatic precipitators -Baghouses Scrubbers -Baffle spray scrubber -Cyclonic spray scrubber -Ejector venturi scrubber -Mechanically aided scrubber -Spray tower -Wet scrubber Sewage treatment -API oil-water separators -Sedimentation (water treatment) -Dissolved air flotation (DAF) -Activated sludge biotreaters -Biofilters -Powdered activated carbon treat ment Vapor recovery systems
Earth Hour is a global event organized by WWF (World Wide Fund for Nature, als o known as World Wildlife Fund) and is held on the last Saturday of March annuall y, asking households and businesses to turn off their non-essential lights and othe r electrical appliances for one hour to raise awareness towards the need to take a ction on climate change. Earth hour was conceived by WWF and The Sydney Morning Herald in 2007, wh en 2.2 million residents of Sydney participated by turning off all non-essential light s. Following Sydney's lead, many other cities around the world adopted the event i n 2008. Earth Hour 2010 will take place on March 27, 2010 from 8:30 pm to 9:30 pm, local time.