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Public Health AssignmentOn Water Pollution and Global Warming
Submitted to: Dr. Maleeha Azeem (Mea)
Submitted By: Mushfiqur Rahman
Id: 1110685030
Section: 7
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INDEX:
WATER POLLUTION:oWHAT IS WATER POLLUTION?oTHE SOURCES OF WATER POLLUTIONoTHE COMMON POLLUTANTSoHEALTH HAZARDS OF WATER POLLUTION
GLOBAL WARMING:oWHAT IS GLOBAL WARMING?o CAUSES OF GLOBAL WARMINGo CONSEQUENCES OF GLOBAL WARMING
REFERENCES
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WATER POLLUTION
What Is Water Pollution?
Water pollution refers to degradation of water quality. It is a large set of adverse effects upon waterbodies such as lakes, rivers, oceans, and groundwater caused by human activities. Water pollution can
be defined as "the presence of a substance in the environment that because of its chemical composition
or quantity prevents the functioning of natural processes and produces undesirable environmental and
health effects
Water pollution can be defined in many ways. Usually, it means one or more substances havebuilt up in water to such an extent that they cause problems for animals or people. This could
affect the health of all the plants, animals, and humans whose lives depend on the river.
Dozens of times a day those of us who live in the industrialized nations of the world enjoy ablessing denied to 75 percent of the world population: abundant supplies of clean water. For
centuries water has been used as a dumping ground for human sewage and industrial wastes.
Added to them are the materials leached out and transported from land by water percolating
through the soil and running off its surface to aquatic ecosystems. Thus the term water
pollution refers to "Water contamination by a variety of chemical substances or
eutrophication caused by several nutrients and fertilizers (Southwick, 1976)".
Water is typically referred to as polluted when it is impaired by anthropogenic contaminantsand either does not support a human use or undergoes a marked shift in its ability to support its
constituent biotic communities.
U.S. Department of Health Education and Welfare defines water pollution as "The adding towater ofany substance, or the changing ofwater's physical and chemical characteristics
in any way which interferes with its use oflegitimate purposes".
Water is typically referred to as polluted when it is impaired by anthropogenic contaminantsand either does not support a human use, such as drinking water, and/or undergoes a marked
shift in its ability to support its constituent biotic communities, such as fish. Natural
phenomena such as volcanoes, algae blooms, storms, and earthquakes also cause major
changes in water quality and the ecological status of water.
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The sources of Water Pollution:
There two major kinds of pollution sources:
- Point sources
- Non-point sources
Point sources:
Point source water pollution refers to contaminants that enter a waterway from a single, identifiable
source, such as a pipe or ditch. Examples of sources in this category include discharges from a sewage
treatment plant, a factory, or a city storm drain. The U.S. Clean Water Act (CWA) defines point
source for regulatory enforcement purposes. The CWA definition of point source was amended in
1987 to include municipal storm sewer systems, as well as industrial storm water, such as from
construction sites.
Nonpoint sources:
Nonpoint source pollution refers to diffuse contamination that does not originate from a single
discrete source. NPS pollution is often the cumulative effect of small amounts of contaminants
gathered from a large area. A common example is the leaching out of nitrogen compounds from
fertilized agricultural lands. Nutrient runoffin storm water from "sheet flow" over an agriculturalfield
or a forest is also cited as examples of NPS pollution.
Contaminated storm water washed off of parking lots, roads and highways, called urban runoff, is
sometimes included under the category of NPS pollution. However, this runoff is typically channeled
into storm drain systems and discharged through pipes to local surface waters, and is a point source.
However where such water is not channeled and drains directly to ground it is a non-point source.
The Common Pollutants:
Infectious Agents
These are disease causing agents or pathogens, e.g. bacteria, viruses, protozoa, parasites. These come
from raw sewage and animal waste. These are measured by the amount of Coliform bacteria present.
http://en.wikipedia.org/wiki/Point_source_water_pollutionhttp://en.wikipedia.org/wiki/Water_pipehttp://en.wikipedia.org/wiki/Ditchhttp://en.wikipedia.org/wiki/Sewage_treatmenthttp://en.wikipedia.org/wiki/Sewage_treatmenthttp://en.wikipedia.org/wiki/Factoryhttp://en.wikipedia.org/wiki/Storm_drainhttp://en.wikipedia.org/wiki/Clean_Water_Acthttp://en.wikipedia.org/wiki/Regulationhttp://en.wikipedia.org/wiki/Municipalityhttp://en.wikipedia.org/wiki/Storm_sewerhttp://en.wikipedia.org/wiki/Constructionhttp://en.wikipedia.org/wiki/Nonpoint_source_pollutionhttp://en.wikipedia.org/wiki/Nonpoint_source_pollutionhttp://en.wikipedia.org/wiki/Nonpoint_source_pollutionhttp://en.wikipedia.org/wiki/Nitrogenhttp://en.wikipedia.org/wiki/Surface_runoffhttp://en.wikipedia.org/wiki/Stormwaterhttp://en.wikipedia.org/wiki/Agricultural_fieldhttp://en.wikipedia.org/wiki/Agricultural_fieldhttp://en.wikipedia.org/wiki/Agricultural_fieldhttp://en.wikipedia.org/wiki/Foresthttp://en.wikipedia.org/wiki/Parking_lothttp://en.wikipedia.org/wiki/Roadhttp://en.wikipedia.org/wiki/Highwayhttp://en.wikipedia.org/wiki/Urban_runoffhttp://en.wikipedia.org/wiki/Urban_runoffhttp://en.wikipedia.org/wiki/Highwayhttp://en.wikipedia.org/wiki/Roadhttp://en.wikipedia.org/wiki/Parking_lothttp://en.wikipedia.org/wiki/Foresthttp://en.wikipedia.org/wiki/Agricultural_fieldhttp://en.wikipedia.org/wiki/Stormwaterhttp://en.wikipedia.org/wiki/Surface_runoffhttp://en.wikipedia.org/wiki/Nitrogenhttp://en.wikipedia.org/wiki/Nonpoint_source_pollutionhttp://en.wikipedia.org/wiki/Constructionhttp://en.wikipedia.org/wiki/Storm_sewerhttp://en.wikipedia.org/wiki/Municipalityhttp://en.wikipedia.org/wiki/Regulationhttp://en.wikipedia.org/wiki/Clean_Water_Acthttp://en.wikipedia.org/wiki/Storm_drainhttp://en.wikipedia.org/wiki/Factoryhttp://en.wikipedia.org/wiki/Sewage_treatmenthttp://en.wikipedia.org/wiki/Sewage_treatmenthttp://en.wikipedia.org/wiki/Ditchhttp://en.wikipedia.org/wiki/Water_pipehttp://en.wikipedia.org/wiki/Point_source_water_pollution8/3/2019 PBH Final Mahi
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Oxygen-demanding wastes
Sewage, animal manure or biodegradable organic wastes, which can be decomposed by aerobic
bacteria which cause a reduction in dissolved oxygen (DO) results in suffocating for oxygen-
consuming organisms (fish). These are measured by biological oxygen demand (BOD).
Water soluble Inorganic chemicals
Water-soluble inorganic chemicals, includes acids, salts, and metals. Make water unfit to consume and
use for irrigation. Also can harm organisms and cause material corrosion.
Organic chemicals
Detergents
Disinfection by-products found in chemically disinfected drinking water, such as chloroform Food processing waste, which can include oxygen-demanding substances, fats and grease Insecticides and herbicides, a huge range oforgan halides and other chemical compounds Petroleum hydrocarbons, including fuels (gasoline, diesel fuel, jet fuels, and fuel oil) and
lubricants (motor oil), and fuel combustion byproducts, from storm water runoff.
Tree and bush debris from logging operations Volatile organic compounds (VOCs), such as industrial solvents, from improper storage. Chlorinated solvents, which are dense non-aqueous phase liquids (DNAPLs), may fall to the
bottom of reservoirs, since they don't mix well with water and are denser.
o Polychlorinated biphenyl (PCBs)o Trichloroethylene
Perchlorate Various chemical compounds found in personal hygiene and cosmetic products
Inorganic water pollutants include:
Acidity caused by industrial discharges (especially sulfur dioxide from power plants) Ammonia from food processing waste Chemical waste as industrial by-products Fertilizers containing nutrients--nitrates and phosphates--which are found in storm water runoff
from agriculture, as well as commercial and residential use
http://en.wikipedia.org/wiki/Detergentshttp://en.wikipedia.org/wiki/Disinfection_by-producthttp://en.wikipedia.org/wiki/Disinfectionhttp://en.wikipedia.org/wiki/Drinking_waterhttp://en.wikipedia.org/wiki/Chloroformhttp://en.wikipedia.org/wiki/Food_processinghttp://en.wikipedia.org/wiki/Insecticidehttp://en.wikipedia.org/wiki/Herbicidehttp://en.wikipedia.org/wiki/Organohalidehttp://en.wikipedia.org/wiki/Chemical_compoundshttp://en.wikipedia.org/wiki/Petroleumhttp://en.wikipedia.org/wiki/Gasolinehttp://en.wikipedia.org/wiki/Diesel_fuelhttp://en.wikipedia.org/wiki/Fuel_oilhttp://en.wikipedia.org/wiki/Combustionhttp://en.wikipedia.org/wiki/Stormwaterhttp://en.wikipedia.org/wiki/Surface_runoffhttp://en.wikipedia.org/wiki/Treehttp://en.wikipedia.org/wiki/Logginghttp://en.wikipedia.org/wiki/Volatile_organic_compoundshttp://en.wikipedia.org/wiki/Solventhttp://en.wikipedia.org/wiki/Chlorinated_solventhttp://en.wikipedia.org/wiki/DNAPLhttp://en.wikipedia.org/wiki/Polychlorinated_biphenylhttp://en.wikipedia.org/wiki/Trichloroethylenehttp://en.wikipedia.org/wiki/Perchloratehttp://en.wikipedia.org/wiki/Hygienehttp://en.wikipedia.org/wiki/Cosmeticshttp://en.wikipedia.org/wiki/Acidityhttp://en.wikipedia.org/wiki/Sulfur_dioxidehttp://en.wikipedia.org/wiki/Power_plantshttp://en.wikipedia.org/wiki/Ammoniahttp://en.wikipedia.org/wiki/Chemical_wastehttp://en.wikipedia.org/wiki/Fertilizerhttp://en.wikipedia.org/wiki/Nitrateshttp://en.wikipedia.org/wiki/Phosphatehttp://en.wikipedia.org/wiki/Agriculturehttp://en.wikipedia.org/wiki/Agriculturehttp://en.wikipedia.org/wiki/Phosphatehttp://en.wikipedia.org/wiki/Nitrateshttp://en.wikipedia.org/wiki/Fertilizerhttp://en.wikipedia.org/wiki/Chemical_wastehttp://en.wikipedia.org/wiki/Ammoniahttp://en.wikipedia.org/wiki/Power_plantshttp://en.wikipedia.org/wiki/Sulfur_dioxidehttp://en.wikipedia.org/wiki/Acidityhttp://en.wikipedia.org/wiki/Cosmeticshttp://en.wikipedia.org/wiki/Hygienehttp://en.wikipedia.org/wiki/Perchloratehttp://en.wikipedia.org/wiki/Trichloroethylenehttp://en.wikipedia.org/wiki/Polychlorinated_biphenylhttp://en.wikipedia.org/wiki/DNAPLhttp://en.wikipedia.org/wiki/Chlorinated_solventhttp://en.wikipedia.org/wiki/Solventhttp://en.wikipedia.org/wiki/Volatile_organic_compoundshttp://en.wikipedia.org/wiki/Logginghttp://en.wikipedia.org/wiki/Treehttp://en.wikipedia.org/wiki/Surface_runoffhttp://en.wikipedia.org/wiki/Stormwaterhttp://en.wikipedia.org/wiki/Combustionhttp://en.wikipedia.org/wiki/Fuel_oilhttp://en.wikipedia.org/wiki/Diesel_fuelhttp://en.wikipedia.org/wiki/Gasolinehttp://en.wikipedia.org/wiki/Petroleumhttp://en.wikipedia.org/wiki/Chemical_compoundshttp://en.wikipedia.org/wiki/Organohalidehttp://en.wikipedia.org/wiki/Herbicidehttp://en.wikipedia.org/wiki/Insecticidehttp://en.wikipedia.org/wiki/Food_processinghttp://en.wikipedia.org/wiki/Chloroformhttp://en.wikipedia.org/wiki/Drinking_waterhttp://en.wikipedia.org/wiki/Disinfectionhttp://en.wikipedia.org/wiki/Disinfection_by-producthttp://en.wikipedia.org/wiki/Detergents8/3/2019 PBH Final Mahi
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Heavy metals from motor vehicles (via urban storm water runoff) and acid minedrainage Silt (sediment) in runoff from construction sites, logging, slash and burn practices or land
clearing sites
Macroscopic pollutionlarge visible items polluting the watermay be termed "floatables" in anurban storm water context, or marine debris when found on the open seas, and can include such items
as:
Trash or garbage (e.g. paper, plastic, or food waste) discarded by people on the ground, alongwith accidental or intentional dumping of rubbish, that are washed by rainfall into storm drains
and eventually discharged into surface waters
Nurdles, small ubiquitous waterborne plastic pellets Shipwrecks, large derelict ships
Thermal pollution
Thermal pollution is the rise or fall in the temperature of a natural body of water caused by human
influence. Thermal pollution, unlike chemical pollution, results in a change in the physical properties
of water. A common cause of thermal pollution is the use of water as a coolant by power plants and
industrial manufacturers. Elevated water temperatures decreases oxygen levels (which can kill fish)
and affects ecosystem composition, such as invasion by new thermophilic species. Urban runoff may
also elevate temperature in surface waters.
Thermal pollution can also be caused by the release of very cold water from the base of reservoirs into
warmer rivers.
Plant nutrients
Nitrates, phosphates, ammonium originated mostly from fertilizers. Cause excessive algal and plantgrowth (algal bloom) that lower oxygen levels when they decompose leading to eutrophication
(lectures on Ecology and Agriculture).
Sediment
Mud, silt, sand which disrupts photosynthesis and transports large amounts of other, adsorbed
pollutants. These are bad for Aquatic animals.
http://en.wikipedia.org/wiki/Heavy_metalshttp://en.wikipedia.org/wiki/Motor_vehiclehttp://en.wikipedia.org/wiki/Urban_runoffhttp://en.wikipedia.org/wiki/Acid_mine_drainagehttp://en.wikipedia.org/wiki/Acid_mine_drainagehttp://en.wikipedia.org/wiki/Acid_mine_drainagehttp://en.wikipedia.org/wiki/Silthttp://en.wikipedia.org/wiki/Sedimenthttp://en.wikipedia.org/wiki/Constructionhttp://en.wikipedia.org/wiki/Logginghttp://en.wikipedia.org/wiki/Slash_and_burnhttp://en.wikipedia.org/wiki/Marine_debrishttp://en.wikipedia.org/wiki/Trash_%28material%29http://en.wikipedia.org/wiki/Rainfallhttp://en.wikipedia.org/wiki/Storm_drainhttp://en.wikipedia.org/wiki/Plastichttp://en.wikipedia.org/wiki/Shipwreckhttp://en.wikipedia.org/wiki/Coolanthttp://en.wikipedia.org/wiki/Power_plantshttp://en.wikipedia.org/wiki/Ecosystemhttp://en.wikipedia.org/wiki/Thermophilichttp://en.wikipedia.org/wiki/Reservoirhttp://en.wikipedia.org/wiki/Reservoirhttp://en.wikipedia.org/wiki/Thermophilichttp://en.wikipedia.org/wiki/Ecosystemhttp://en.wikipedia.org/wiki/Power_plantshttp://en.wikipedia.org/wiki/Coolanthttp://en.wikipedia.org/wiki/Shipwreckhttp://en.wikipedia.org/wiki/Plastichttp://en.wikipedia.org/wiki/Storm_drainhttp://en.wikipedia.org/wiki/Rainfallhttp://en.wikipedia.org/wiki/Trash_%28material%29http://en.wikipedia.org/wiki/Marine_debrishttp://en.wikipedia.org/wiki/Slash_and_burnhttp://en.wikipedia.org/wiki/Logginghttp://en.wikipedia.org/wiki/Constructionhttp://en.wikipedia.org/wiki/Sedimenthttp://en.wikipedia.org/wiki/Silthttp://en.wikipedia.org/wiki/Acid_mine_drainagehttp://en.wikipedia.org/wiki/Urban_runoffhttp://en.wikipedia.org/wiki/Motor_vehiclehttp://en.wikipedia.org/wiki/Heavy_metals8/3/2019 PBH Final Mahi
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Radioactive materials
Radium, uranium, etc. may come either from natural or anthropogenic sources.
Heat
From cooling water for power plants & other industrial plants which lowers solubility of oxygen in
water. Also affect aquatic lives directly.
The Health Hazards of Water Pollution:
Water-borne diseases are infectious diseases spread primarily through contaminated water.Though these diseases are spread either directly or through flies or filth, water is the chief
medium for spread of these diseases and hence they are termed as water-borne diseases.
Most intestinal (enteric) diseases are infectious and are transmitted through fecal waste.Pathogens which include virus, bacteria, protozoa, and parasitic worms - are disease-
producing agents found in the feces of infected persons. These diseases are more prevalent in
areas with poor sanitary conditions. These pathogens travel through water sources and
interfuses directly through persons handling food and water. Since these diseases are highly
infectious, extreme care and hygiene should be maintained by people looking after an infected
patient. Hepatitis, cholera, dysentery, and typhoid are the more common water-borne diseases
that affect large populations in the tropical regions.
Freshwater resources all over the world are threatened not only by over exploitation and poormanagement but also by ecological degradation. The main source of freshwater pollution can
be attributed to discharge of untreated waste, dumping of industrial effluent, and run-off from
agricultural fields. Industrial growth, urbanization and the increasing use of synthetic organic
substances have serious and adverse impacts on freshwater bodies. It is a generally accepted
fact that the developed countries suffer from problems of chemical discharge into the water
sources mainly groundwater, while developing countries face problems of agricultural run-off
in water sources. Polluted water like chemicals in drinking water causes problem to health and
leads to water-borne diseases which can be prevented by taking measures can be taken even at
the household level.
http://edugreen.teri.res.in/explore/water/health.htm#groundhttp://edugreen.teri.res.in/explore/water/health.htm#chemhttp://edugreen.teri.res.in/explore/water/health.htm#disehttp://edugreen.teri.res.in/explore/water/health.htm#meashttp://edugreen.teri.res.in/explore/water/health.htm#meashttp://edugreen.teri.res.in/explore/water/health.htm#disehttp://edugreen.teri.res.in/explore/water/health.htm#chemhttp://edugreen.teri.res.in/explore/water/health.htm#ground8/3/2019 PBH Final Mahi
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A large number of chemicals that either exist naturally in the land or are added due to humanactivity dissolve in the water, thereby contaminating it and leading to various diseases.
Pesticides. The organophosphates and the carbonates present in pesticides affect and damagethe nervous system and can cause cancer. Some of the pesticides contain carcinogens that
exceed recommended levels. They contain chlorides that cause reproductive and endocrinal
damage.
Lead. Lead is hazardous to health as it accumulates in the body and affects the central nervoussystem. Children and pregnant women are most at risk.
Fluoride. Excess fluorides can cause yellowing of the teeth and damage to the spinal cord andother crippling diseases.
Nitrates. Drinking water that gets contaminated with nitrates can prove fatal especially toinfants that drink formula milk as it restricts the amount of oxygen that reaches the brain
causing the blue baby syndrome. It is also linked to digestive tract cancers. It causes algae to
bloom resulting in eutrophication in surface water.
Petrochemicals. Benzene and other petrochemicals can cause cancer even at low exposurelevels.
Chlorinated solvents. These are linked to reproduction disorders and to some cancers. Arsenic. Arsenic poisoning through water can cause liver and nervous system damage,
vascular diseases and also skin cancer.
Other heavy metals. Heavy metals cause damage to the nervous system and the kidney, andother metabolic disruptions.
Salts. It makes the fresh water unusable for drinking and irrigation purposes. Exposure to polluted water can cause diarrhea, skin irritation, respiratory problems, and other
diseases, depending on the pollutant that is in the water body. Stagnant water and other
untreated water provide a habitat for the mosquito and a host of other parasites and insects that
cause a large number of diseases especially in the tropical regions. Among these, malaria is
undoubtedly the most widely distributed and causes most damage to human health.
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Common Diseases Transmitted to Humans through Contaminated Drinking Water
Type of Organism Disease Effects
Bacteria Typhoid fever Diarrhea, severe vomiting, enlarged spleen,
inflamed intestine; often fatal if untreated
Cholera Diarrhea, severe vomiting, dehydration;
often fatal if untreated
Bacterial dysentery Diarrhea; rarely fatal except in infants
without proper treatment
Enteritis Severe stomach pain, nausea, vomiting;
rarely fatal
Viruses Infectious hepatitis Fever, severe headache, loss of appetite,
abdominal pain, jaundice, enlarged liver;
rarely fatal but may cause permanent liver
damage
Parasitic protozoa Amoebic dysentery Severe diarrhea, headache, abdominal
pain, chills, fever; if not treated can cause
liver abscess, bowel perforation, and
death
Giardiasis Diarrhea, abdominal cramps, flatulence,belching, fatigue
Parasitic worms Schistosomiasis Abdominal pain, skin rash, anemia, chronic
fatigue, and chronic general ill health
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Infectious diseases caused by pathogens (usually microorganisms) from animal fecal origins,of which the most common occur in developing countries involving:
o Typhoido Giardiasiso Amoebiasiso Ascariasiso Hookworm
Diseases caused by polluted beach water including:o Gastroenteritiso Dhiarrheao Encephalitiso Stomach cramps and acheso Vomitingo Hepatitiso Respiratory infections
Liver damage and even cancer (due to DNA damage) caused by a series of chemicals (e.g.,chlorinated solvents, MTBE)
Kidney damage caused by a series of chemicals Neurological problems - damage of the nervous system usually due to the presence of
chemicals such as pesticides (i.e., DDT)
Reproductive and endocrine damage including interrupted sexual development, inability tobreed, degraded immune function, decreased fertility and increase in some types of cancers
caused by a series of chemicals including endocrine disruptorswhich
Thyroid system disorders (a common example is exposure through perchlorate which is achemical contaminating large water bodies such as Colorado River)
Increased water pollution creates breeding grounds for malaria-carrying mosquitoes killing 1.2-2.7 million people a year
A series of less serious health effects could be associated by bathing into contaminated water(i.e., polluted beach water) including:
o Rasheso Ear acheso Pink eyes
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GLOBAL WARMING
What is Global Warming?
Global warming means a long-term rise in global average temperature. The temperature at or near
the surface of the Earth is determined by four main factors:
The amount of sunlight Earth receives. The amount of sunlight Earth reflects. Retention of heat by the atmosphere. Evaporation and condensation ofwater vapor.
More particularly, the constant increase in temperature that started a century ago is assumed to be
caused mostly by pollution from human activities, including the combustion of fossil fuels and
deforestation. In fact, global warming represents an enhancement of the greenhouse effect. The
anthropogenic greenhouse effect would be a more suitable term for global warming. The
Greenhouse Effect is what keeps Earth warm enough for people to live on (If there was no such
GH effect the Earths average temperature which would be 34-350C colder than it is now.
The average global air temperature is about 150C), but a build-up in the gases that generate
this warmth is overheating our planet and causing global warming. Increasing temperatures have
already resulted in an increase in extreme weather events, loss of sea ice and glaciers, rising sea
level, and harm to wildlife.
Causes of Global Warming:
Carbon Dioxide (CO2)Carbon dioxide is the most vital anthropogenic greenhouse gas.
Carbon dioxide is released from the interior of the Earth (volcanoes),and produced by respiration of biota, soil processes, oceanic
evaporation, as well as human activities, such as deforestation (which
causes 20% of the annual increase in this gas) and burning of fossil
fuels. Deforestation might be sending an annual 4 billion tons of Fig: CO2 Emission
carbon dioxide into the atmosphere that would otherwise be absorbed by plants during their
metabolic processes.
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Automobile exhausts causes 30% of carbon dioxide emissions in developed countries. The
generation of carbon dioxide as a result of combustion of fossil fuels suggests that if the
present trends continue, then its concentration will double every 50 years.
Chlorofluorocarbons (CFCs)Chlorofluorocarbons (CF2Cl2 and CFCl3), better known as Freon F-11 and F-12,
correspondingly, are entirely anthropogenically produced, are very persistent compounds, used
in spray cans as aerosol propellants and in refrigeration units. They were not present in the
atmosphere until the 1930s. Due to their persistence and to their high efficiency in absorbing
thermal IR, each CFC molecule has the ability to cause the similar amount of global warming,
as much as tens of thousands of carbon dioxide molecules do. It has been anticipated that
around 15% to 25% of the anthropogenic greenhouse effect may be connected to CFCs in the
atmosphere. Because CFCs are highly stable compounds, their residence time in the
atmosphere is lengthy. Even if production of these chemicals is reduced drastically or
eliminated within the next few years, their concentrations in the atmosphere will remain
significant for many years, perhaps for as long as a century.
Water VaporIndeed, water vapor is the most significant greenhouse gas in the Earths atmosphere, in the
sense that it produces more warming than does any other gas. Though on a per molecule basis,
it is a less efficient absorber than is carbon dioxide. On a global scale water vapor is unaffected
by anthropogenic sources and sinks. As a result, water is not normally listed explicitly among
gases whose increasing concentrations are enhancing the greenhouse effect.
Methane (CH4)Major natural contributors are termites as they process wood. Today, rice culture, domestic
ruminant animals, landfills, and our own use of methane as a fuel source supply additional
methane to the atmosphere.Methane is 21 times more effective than carbon dioxide inmaintaining heat in the atmosphere. This results in the deaths of numerous marine animals.About 70% of current emissions of methane are anthropogenic in origin. Methane contributes
15% to 20% to the anthropogenic greenhouse effect. The short atmospheric lifetime of
methane suggests that efforts to reduce methane emissions could be successful in delaying the
raise in the rate of global warming. Yet, control of methane sources is doubtful, since the key
sources involve agricultural practices that would be very difficult to change.
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Nitrous Oxide (N2O)Nitrous oxide, which is comparatively inert, originates primarily from microbial activity in
soils and the oceans, by industrial combustion, automobiles, aircraft, biomass burning, and as a
result of the use of chemical fertilizers. It could be reduced by more watchful use of nitrogen-
containing fertilizers. Nitrous oxide is a stronger greenhouse gas than carbon dioxide or
methane, although it contributes only 5% to the anthropogenic greenhouse effect. Per
molecule, nitrous oxide is 206 times as capable as carbon dioxide in causing an immediate
increase in global warming. However, this gas also has a long residence time; even if emissions
were stabilized or reduced, elevated concentrations of nitrous oxide would carry on for at least
several decades.
Hydrogenated halocarbons (HFCs and HCFCs):These are also entirely anthropogenic gases. They have increased sharply in the atmosphere
over the last few decades, following their use as alternative for CFCs. They usually have
lifetimes of a few years, but still have significant greenhouse effect.
Ozone Gas (O3)Like methane and nitrous oxide, Ozone is a natural greenhouse gas, but one which has a
short residence period. Ozone is formed in the troposphere as a result of pollution from power
plants and motor vehicles, and from forest fires and grass fires, as well as from natural
processes (i.e., by light-induced reaction of pollutants and the phenomenon is called
photochemical smog). As a result of these anthropogenic activities, the levels of ozone in the
troposphere most likely have increased since preindustrial times. Approximately 10% of the
increased global warming potential of the atmosphere, results from the increases in troposphere
ozone, though the value is uncertain.
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Consequences of Global Warming:
Negative impacts:
On climate:
Rising Seas: Greenhouse gases make sea level rise due to thermal expansion of sea water andmelting of polar and mountain ice. The increase in temperature results to sea level raise from
melting glaciers and polar ice caps (adds 0.2 mm annually). It is estimated to be up to 1 meter by
2100. The coastal zone (100 km from the sea) contains: 1.5 billion peoplethats 1 in 4 people
and 17 out of 20 of the worlds largest cities which are now endangered because of global
warming. Results are: flooding of low-lying islands and coastal cities, flooding of coastal
estuaries, wetlands and coral reefs, beach erosion, disruption of coastal fisheries, contamination
of coastal aquifers with salt water, increase in the
vulnerability of coastal areas to flooding from storm
surges and intense rainfall.
Drier conditions: Growing temperatures will also causedrier condition in many important agricultural regions.
The rise of temperature, even to a few degrees, could lead
to the melting of ice shelves that hold back glaciers. This
results in rising sea levels. The Larsen areas of North
Antarctic, South of Chili and Argentina have lost more
than 5,200 sq miles of area due to meltdown of ice caps
and glaciers.
Changes in rainfall patterns: Droughts and fires in some areas, flooding in other areas. Increased likelihood of extreme events: Such as flooding, hurricanes, etc. Melting of the ice caps: Loss of habitat near the poles. Polar bears are now considered to be
seriously endangered by the shortening of their feeding season due to dwindling ice packs.
Melting glaciers: Significant melting of old glaciers is already observed. Increased pollution: High temperature can increase pollution of water and air, which harms
the human body
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Biodiversity: Extinction of some plant and animal species, loss of habitats, disruption ofaquatic life.
Water resources: Disruption in water cycle; increase in evaporation will cause some areas tobecome drier (increased drought), while the increased moisture in the air will result in greater
rainfall in other areas; changes in water supply, decreased water quality, , increased water
pollution from coastal flooding.
Weather Extremes: Prolonged heat waves and droughts, violent storms with more frequencyand intensity.
Forestry: Changes in forest composition and locations, disappearance of some forests,increased fire from drying, loss of wildlife habitat and species.
On sea life:
Coral Reef Bleaching:
Change in temperature and elevated sea level cause loss of algae in the coral. Coral appears white, or bleached. Result is mass death of sea animals, which are dependent on the coral reef.
E.g. the penguin population near Antarctica has been declining as the distance between
them and their food has increased
On other living beings:
Global warming can disrupt the migration, hibernation and reproductive cycles ofcertain types of animals.
Plants and animals will find it difficult to escape or adjust to the consequences of globalwarming because humans occupy so much land.
Farmland or cities disrupt the movement of species between habitats. Changes in forest composition and locations, disappearance of some forests, increased
fire from drying, loss of wildlife habitat and species.
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On human:
Loss of life: Extreme temperatures can directly cause the loss of life (ex: 35,000people died during heat wave in Europe, Aug03). Warmer weather provides an ideal
breeding environment for mosquitoes. Diseases such as West Nile will be more common. Food Production: Shift in food growing areas,changes in crop yield, increased irrigation
demands, increased pests, crop diseases, and weeds in warmer areas. It is the poorest
countries, where many already are subject to hunger, that are the most likely to suffer
significant decreases in agricultural productivity.
Tropical diseases: Global Warming increases drought which lessens the supply of clean drinking
water. E.g. Cholera.
It increases temperature providing an ideal breeding environment formosquitoes. E.g. Dengue fever, Malaria, Yellow fever
Public Health Impacts of Global Warming Heat waves and deaths from hyperthermia Fresh water shortages (due to combined effects of global warming, overpopulation and
water pollution) with wars fought over fresh water
Air pollution related to greenhouse gases (increased disease and death due to heartattack, stroke, asthma, emphysema, lung cancer, allergy)
Ozone depletion leading to increased cataracts, melanoma Extreme weather events (floods and storms) Water-borne and food-borne diseases (toxic algal blooms like red tide, survival of viral
pathogens leading to shellfish poisoning, cholera)
Vector-borne and rodent-borne diseases (mosquitoes, ticks, rodents) Elevated seas levels (population exodus, aquifers threatened in San Francisco and New
Orleans)
Crop failures and famine Economic and political stress may damage public health infrastructure Vector Bone Disease: Disease in humans carried from another warm-blooded animal by
an insect such as a mosquito, tick or sand fly. In 1877 scientists showed for the first
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time that blood-sucking insects were able to carry disease from one warm-blooded
animal to another. .
Infectious diseases: The following diseases are potentially spread by global warming Leishmaniasis Kyasanur Forest disease La Crosse encephalitis Eastern equine encephalitis Japanese encephalitis Oropouche Western equine encephalitis Venezuelan equine encephalitis Onchocerciasi Dengue fever Malaria Yellow fever Chickungunya fever Epidemic polyarthritis West Nile fever St. Louis encephalitis Lyme disease Ehrlichiosis Plague Loaiasis
Impact on air:
The atmospheres ultimate fate is unclear.
More evaporation increase in cloud cover
Clouds close to the earth reflect sunlight cooling effect.
Clouds high in the atmosphere trap heat warming effect.
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Generally:
Cloud cover increases Levels of the greenhouse gas methane may increase Hurricanes range farther north, south on warmer water
On Bangladesh:
This is a topographic map designed to emphasize portions of Bangladesh that are near sea level and
hence could potentially be vulnerable to sea level rise.
With a population of ~150 million, Bangladesh is the 7th most
populous country on Earth and has the highest population density
of any country larger than 1000 km2
in area. As large portions of
Bangladesh are near sea level, sea level rise here has the potential
to displace tens of millions of people.
1 meter rise in sea level will mean:
15-17% of the country under water
Displacement of 15-20 million peoplePositive impacts:
Not all of the effects of global warming appear to be negative ones, however, despite the barrage
of predicted woes.
In colder areas:
In many colder areas, for instance, warmer temperatures would extend the growing season.
Northern countries like Canada and Russia, along with the more northern areas of the United
States, should reap the rewards of longer growing seasons. Several studies have shown that, while
some regions will suffer agriculturally, Americas nationwide food production will not decline
substantially. In fact, recent assessments recommend that the beneficial effects of climate change
would probably offset the adverse ones in Americas general agricultural production. A 1995 study
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conducted by the USDA concluded that even a three to five degree Celsius warming of the
atmosphere shouldnt effect Americas agricultural production notably.
In agriculture:
Even the very thing that is the main cause of global warming could be beneficial to agriculture.
The higher carbon dioxide levels in the atmosphere should increase the efficiency with which
plants use water, possibly offsetting some of the undesirable effects of dryer soils. Higher levels of
carbon dioxide also have a fertilizing effect that would allow plants to grow more quickly. A
carbon dioxide concentration of 550 ppm (parts per million) could raise crop yields in some areas
by thirty to forty percent. Along with the promising positive effects of increased carbon dioxide
concentration, warmer temperatures would make it lucrative to cultivate new land, which could
result in a 0.2 to 1.2 percent increase in agricultural production.
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References:
For Water Pollution:
www.csshome.com/WaterMarine.html
en.wikipedia.org/wiki/Water pollutionwww.water-pollution.org.uk/
www.water-pollution.org.uk/causes.html
www.epa.gov/ebtpages/watewaterpollution.html
For Global Warming:
http://www.ipcc.ch
http://www.weathervane.rff.org/
http://www.igpp.lanl.gov
www.dosomething.org/tipsandtools/11-facts-about-global-warming
www.edf.org/climate/global-warming-facts
http://www.ipcc.ch/http://www.weathervane.rff.org/http://www.igpp.lanl.gov/http://www.dosomething.org/tipsandtools/11-facts-about-global-warminghttp://www.dosomething.org/tipsandtools/11-facts-about-global-warminghttp://www.igpp.lanl.gov/http://www.weathervane.rff.org/http://www.ipcc.ch/