Human impact on the global environment was negligible
before the industrial age. Today, there are numerous indicators of the
damage being caused. Each second of the day: i)
an estimated 1,000 tons of top soil and 3,000 square meters of forest
are lost; ii)
another 2,000 square meters of arable land become desert; and iii)
some 1,000 tons of unwanted gases are released into the atmosphere.
Environmental problems are being compounded by population growth. The
country is in the grip of environmental pollution due to release of CO2,
CO, H2S, SO2, SO4, NO3, particulate matters, fumes, dust particles due
to burning of fossil, fuels, fire wood, coal and release of gases in the
industrialized areas of the country also from the spray of insecticides,
pesticides, herbicides and other toxic chemicals. These phenomena of
environmental scenario generally affect the growth of crops in many
areas of the country.
The global population growth also is considered to be
one of the major driving forces of global climatic change. The effects
of human activities on the global atmosphere have become increasingly
evident during the last decades. As the result of the population
explosion, accelerated urbanization, and continuous industrialization,
new environmental problems like those of greenhouse effects, ozone layer
depletion, acid rains the increased use of pesticides are being created
tremendously. Air is the ocean we breathe. Air supplies us with oxygen,
which is essential for our bodies to live. Air is 99.9% — nitrogen,
oxygen, carbon dioxide, water vapor and inert gases. Human activities
can release substances into the air, some of which can cause problems
for humans, plants, and animals. Air pollution is a major hazard in
today's world. There are several main types of pollution and these
include smog, acid rain, the greenhouse effect, and "holes" in
the ozone layer. One type of air pollution is the release of particle
matters into the air from burning fuels for getting energy. Diesel smoke
is a good example of this particulate matter. The particles are very
small pieces of matter measuring about 2.5 microns or about 0.0001
inches. The exhaust from burning fuels in automobiles, homes, and
industries is a major source of pollution in the air. Some authorities
believe that even the burning of wood and charcoal in fire places and
barbecues can release significant quantities of soot into the air.
Another type of pollution is the release of noxious gases, such as
sulphur dioxide, carbon monoxide, nitrogen oxides, and chemical vapors.
These can take part in further chemical reactions once they are in the
atmosphere, forming some complex substances. Pollution also needs to be
considered inside our homes, offices, and schools. Some of these
pollutants can be created by indoor activities such as smoking and
Man's attitude towards the environment became
unfriendly with the advent of the Industrial Revolution in the 19th
century. Later, it became hostile. It was badly mauled, molested and
crushed. The environmental damage was so wide spread as European
technology spread the globe, that vast areas of the richest forests
turned into dry barren expanse after there were cleared for wood-fuel,
timber products, agriculture and livestock. Throughout the 20th century,
deforestation was carried out on an unprecedented scale in the name of
industrialization. An immediate outcome of this destruction has been a
major contribution to the global warming and creation the hole in the
ozone layer that threatens the very life on Planet Earth.
Air pollutants are released to the atmosphere, which
have suppressed the pollutants contributed by nature thousand-fold. The
magnitude of air pollution has increased alarmingly due to population
explosion, industrialization, urbanization, automobiles and other human
proclivities of greater comfort. Air pollution is the contamination of
the atmosphere by gaseous, liquid or solid wastes or by-product that can
endanger human or plant health or can attack material. Combustion of
firewood, garbages, coals and fossil fuels result in the serious
ejection of oxides of carbon, sulphur and nitrogen, small particulate
and organic compounds, which affect the overall peaceful environment all
the times of the agricultural practices such as pesticides,
agrochemicals and herbicides spray also cause air pollution. The cost of
environmental damage was taking its toll due to mismanagement of six
environmental areas - municipal and solid waste, urban air pollution,
cultivable and rangeland degradation, deforestation and destruction of
mangrove forests. Financial loss of municipal solid and liquid waste
costs $883 million, urban air pollution $369 million, soil in crop land
degradation $357 million, rangeland degradation $125 million,
deforestation $28 million and destruction of mangrove forests $15.7
Pesticides are being indiscriminately used in
agricultural farms, sprayed onto the livestock, contaminating our food
and water. Ironically some of the pesticides used with the intention of
protecting crops, infest food and end up having the opposite effects.
Their residues accumulate in the body tissues, where they play havoc
with our health. Operation of automobiles on the road releases
significant quantities of oxides of C, S, N, CH4, Pb, Cd, traces of
heavy metals, and chlorofluorocarbons (CFCs). Aerosol spray, freon
gases, hydrocarbons and toxic aromatic compounds, whereas incineration
of municipal wastes release acid fumes, particulate matter and reactive
and odorous compounds. The toxic substances in the environment
constitute a serious threat to human health as these substances can
enter the human body through air, water and food in varying amounts in
each day throughout a lifetime. Inhalation of air, which is polluted
with biological and toxic substances, may produce various disorders such
as respiratory and pulmonary diseases, skin and eye diseases, allergy
Air pollution may cause increased illness,
contamination of surface water, impaired growth of agricultural crops,
deterioration of materials and loss of amenity. Therefore, it is
necessary to maintain a reasonably good air quality to protect human
health and environment from adverse effects of pollutants. This can be
achieved by controlling the emission of pollutants at source, for
emissions and regular monitoring of pollution levels in air, for which
expertise should be enhanced through training programmes and
organization of seminars and symposia. Air pollution also causes the
appearance and incidence of chronic bronchitis, optic irritation and
lung carcinoma among urban population. The release of carbon monoxide
(CO) in the atmosphere affects the central nervous system even at low
concentration. Both SO2 and NO2, when inhaled irritate the respiratory
system. The SO2, which causes formation of acidic condition in the
atmosphere, causes damages to crops and forest, erosion of buildings and
structures. The main air pollutants released from industrial operations
include particulate matters, sulphur oxides, hydrocarbons, ozone, oxides
of carbon and nitrogen.
It is estimated that annually several million tons of
these pollutants are emitted by photochemical plants, smelting
processes, iron and steel mills, pulp and paper mills, coal cleaning and
coke production, cement, paints, glass manufacturing etc. petrochemical
and paper mills release highly toxic elements in the atmosphere. Several
industrial operations such as metallurgy, electroplating, manufacturing
processes, mining, milling and commercial operations release traces of
heavy metals into the environment from where, these metals can enter
human body through air, water and food chain. These metals (Hg, Cd, Pb,
Ni, Cr, Co, Se, Sb, As, Sn, Br, Bi, Ti, etc.) accumulate in various
organs such as liver, heart, lung and brain and cause various disorders
in the body. These metals cause hepatitis, anemia, insomnia, dizziness,
hallucination, ostomalicia, etc. These metals being biologically
non-degradable accumulate in the vital organs of human being such as
brain, nervous system, kidney, liver, intestinal tract and lungs, and
adversely affect the biochemical processes.
The elements are divided into four classes according
to their potential for pollution.
VERY HIGH POTENTIAL POLLUTION: Ag,
Au, Cd, Cr, Cu, Hg, Pb, Sb, Sn, Ji and Zn.
HIGH POTENTIAL POLLUTION: Ba,
Bi, Ca, Fe, Mn, Mo, Po, T, U.
MODERATE POTENTIAL POLLUTION: Al, As, B, Be, Br,
Cl, Co, F, Ge, K, Li, Na, Ni, Rb, V and W.
LOW POTENTIAL POLLUTION: Ga,
La, Mg, Nb, Si, Ta and Zr.
ROLE OF SOME ELEMENTS IN ATMOSPHERE POLLUTION:
It may rise from mining, burning
coal, use of insecticides or impure sulphuric acid; serious pollution
has occurred in some regions.
BERYLLIUM (Be): Occurs
in industrial smokes.
CALCIUM (Ca): Large
amounts of Ca are applied to agricultural land as fertilizers.
CADMIUM (Cd): Fresh
water pollution has been serious.
CHROMIUM (Cr): The
amount of Cr mined is large compared with its annual cycle in nature.
COPPER (Cu): Common
pollutant of fresh water, also common in industrial smoke. Large amounts
are applied to some agricultural soils as fungicide.
FLUORINE (F): Air
and soil pollution by F causes serious local problems. Agriculture soils
receive much F as an impurity in superphosphate fertilizers.
HYDROGEN (H): Atmospheric
H has been increased 50-1000 fold by nuclear explosions.
MERCURY (Hg): Some
soils are seriously polluted by organic mercurials used as fungicides.
IODINE (I): Burning
algae can contaminate the atmosphere with I on a continental scale.
Reactor accidents may release 131, to the biosphere.
POTASSIUM (K): Large
amounts of K are applied to agricultural soils as fertilizers.
NITROGEN (N): Large
amounts of N are applied to agricultural land as fertilizers and N is a
major constituent of sewage, which pollutes many rivers.
NICKEL (Ni): Nickel
in industrial smoke and other wastes causes local pollution of air and
PHOSPHORUS (P): Large
amounts of phosphates are applied to agricultural soils as fertilizers
and large amounts are discharged to rivers in sewage.
SULPHUR (S): SO2
is a serious global pollutant of the atmosphere. S is applied to some
agricultural soils in large amounts as a fungicide.
Antimony in industrial smoke may
cause lung disease.
Sr is the most potentially hazardous of fission products to mammals.
URANIUM (U): Local
pollution of rivers by U has occurred in the USA.
VANADIUM (V): V
in industrial smoke may cause lung disease. V is also a rare local
pollutant of rivers.
ZINC (Zn): Zn
in industrial smoke may cause lung disease. Zn is a common local
pollutant of rivers.
AFFECT OF AIR POLLUTION ON OUR HEALTH: Air
pollution can affect our health in many ways with both short-term and
long-term effects. Different groups of individuals are affected by air
pollution in different ways. Some individuals are much more sensitive to
pollutants than are others. Young children and elderly people often
suffer from the effects of air pollution. People with health problems
such as asthma, heart and lung disease may also suffer more when the air
is polluted. The extent to which an individual is harmed by air
pollution usually depends on the total exposure to the damaging
chemicals, i.e. the duration of exposure and the concentration of the
chemicals must be taken into account.
SHORT-TERM EFFECTS: Examples
of short-term effects include irritation to the eyes, nose and throat,
and upper respiratory infections such as bronchitis and pneumonia. Other
symptoms can include headaches, nausea, and allergic reactions.
Short-term air pollution can aggravate the medical conditions of
individuals with asthma and emphysema. In the great "Smog
Disaster" in London in 1952, four thousand people died in a few
days due to the high concentrations of pollution.
LONG-TERM EFFECTS: Long-term
health effects can include chronic respiratory disease, lung cancer,
heart disease, and even damage to the brain, nerves, liver, or kidney.
Continual exposure to air pollution affects the lungs of growing
children and may aggravate or complicate medical conditions in the
elderly. It is estimated that half a million people die prematurely
every year in the United States as a result of smoking cigarettes.
Research into the health effects of air pollution is ongoing. Medical
conditions arising from air pollution can be very expensive. Health care
costs, lost productivity in the workplace, and human welfare impacts
cost billions of dollars each year.
There are many forms of air pollution, which threaten
the quality of life. Industrial pollution and hazards, air and noise
pollution, municipal water supplies, sewage, sanitation, solid wastes
are the main factors, which cause air pollution. Industrial pollution is
the major problem, because of air pollution and hazardous nature of many
industrial sites, wastes and by-products. Pakistan generates over 50,000
tons of solid waste per day; out of which only 20-25 % is collected, but
still not manage properly, causing series air, water and land pollution
and health hazards. The industrial units and factories generally dump
their solid and liquid wastes in spaces adjacent to their sites, sewers,
nallahs, or in municipal sewage. There is hardly any control on the
gases and particulate matter emission into atmosphere. In the urban
areas, pollution of air by vehicles and industries is a recurring and
persistent environmental health hazard. Toxic gases such as CO, SO2 and
N2O, and particulate matter, soot, produce smoggy and hazardous
conditions are found in most of the urban centres. Most of the urban
dwellers in big cities of Pakistan are exposed to polluted air and
fumes, high levels of lead from burning of gasoline soot and smog from
diesel. Sewage and gutter water, which is reintroduced into the drinking
water supply through leakage and seepage is a chronic problem in the
cities. Toxic and hazardous wastes enter soils and vegetation and into
the food chain. Application of pesticides, insecticides, agrochemicals,
etc. bring harmful to human population. There are other factors, which
play a pivotal role in the pollution of atmospheric air .
OUTDOOR AIR POLLUTION:
Smog is a type of large-scale
outdoor pollution. It is caused by chemical reactions between pollutants
derived from different sources, primarily automobile exhaust and
industrial emissions. Cities are often centers of these types of
activities and many suffer from the effects of smog, especially during
the warm months of the year. For each city, the exact causes of
pollution may be different. Depending on the geographical location,
temperature, wind and weather factors, pollution is dispersed
differently. However, sometimes this does not happen and the pollution
can build up to dangerous levels
A temperature inversion occurs when air close to the
earth is cooler than the air above it. Under these conditions, the
pollution cannot rise and be dispersed. Cities surrounded by mountains
also experience trapping of pollution. Inversion can happen in any
season. Winter inversions are likely to cause particulate and carbon
monoxide pollution. Summer inversions are more likely to create smog and
dust. Another consequence of outdoor air pollution is acid rain. When a
pollutant, such as sulphuric acid combines with droplets of water in the
air, the water (or snow) can become acidified. The effects of acid rain
on the environment can be very serious. It damages plants by destroying
their leaves, it poisons the soil and changes the chemistry of lakes and
streams. Damage due to acid rain kills trees and harms animals, fish,
and other wildlife.
The greenhouse effect, also referred to as global
warming, is generally believed to come from the build up of carbon
dioxide gas in the atmosphere. Carbon dioxide is produced when fuels are
burned. Plants convert carbon dioxide back to oxygen, but the release of
carbon dioxide from the human activities is higher than the world's
plants can process. This situation is made worse, since many of the
earth's forests are being removed, and plant life is being damaged by
acid rain. Thus, the amount of carbon dioxide in the air is continuing
to increase. This buildup acts like a blanket and traps heat close to
the surface of our earth. Changes of even a few degrees will affect us
all through changes in the climate and even the possibility that the
polar ice caps may melt. One of the consequences of polar ice cap
melting would be a rise in global sea level, resulting in widespread
coastal flooding. Ozone depletion is another result of pollution.
Chemicals released by our activities affect the stratosphere, one of the
atmospheric layers surrounding earth. The ozone layer in the
stratosphere protects the earth from harmful ultraviolet radiation from
the sun. Release of chlorofluorocarbons (CFC's) from aerosol cans,
cooling systems and refrigerator equipment removes some of the ozone,
causing "holes"; to open up in this layer and allowing the
radiation to reach the earth. Ultraviolet radiation is known to cause
skin cancer and has damaging effects on plants and wildlife .
INDOOR AIR POLLUTION:
Many people spend large portion
of time indoors — as much as 80-90% of their lives. We work, study,
eat, drink and sleep in enclosed environments, where air circulation may
be restricted. For these reasons, some experts feel that more people
suffer from the effects of indoor air pollution than outdoor pollution.
There are many sources of indoor air pollution. Tobacco smoke, cooking
and heating appliances, and vapors from building materials, paints,
furniture, etc. cause pollution inside buildings. Radon is a radioactive
gas released from the earth, and it can be found concentrated in
basements in some parts of the United States. Pollution exposure at home
and work is often greater than outdoors. The expert estimates that
indoor air pollutant levels are 25-62% greater than outside levels and
can pose serious problems. Both indoor and outdoor pollution need to be
controlled and/or prevented.
Global environmental change is nothing new. Abundant
evidence exists of past climates radically different from today.
However, as we have already entered in the 21st Century, there is a new
agent of global environmental change and that is 'Mankind'. The
exploitation of the world's natural resources-notably coal, oil and gas
to provide energy and food for a growing, and increasingly affluent,
global population has been changing the composition of the atmosphere.
The by-products, of industrialization and resource use include the
so-called 'greenhouse gases' carbon dioxide (CO2), methane (CH4), the
chloroflurocarbons (CFCs), nitrous oxide (N2O) and tropospheric ozone
(O3) and many other gases and particulates. These air pollutants have
far reaching effects on human health as well as on plant growth and
other living things on the earth. These gases are emitted as a result of
fossil fuels combustion and deforestation, with a proportion remaining
in the atmosphere. For instance, over the last 200 years, atmospheric
CO2 has increased in concentration by 25%. The CO2 concentration is
presently growing at a rate of nearly 0.5% per annum as we spew about 7
billion tons of carbon dioxide into the atmosphere annually. Methane has
more than doubled over the same time period. Chloroflurocarbons (CFCs)
concentrations, virtually negligible 50 years ago, but at present are
responsible for about 20% of recent changes in global warming.
One hears about CO2 referred to as a polluting gas,
but it is also a life giver, because the removal of carbon dioxide from
our atmosphere would lead quickly to the extermination of all plant and
animal life. The energy cycle that nature has provided is miraculous and
beautifully well balanced. Plants turn water and carbon dioxide into
food, fuel and oxygen, while man and other animals eat the food and burn
the fuel in carbon dioxide, so reversing the process. Large changes in
global climate from increasing concentrations of carbon dioxide and
other greenhouse gases are distinct possibilities for the 21st century.
Many metabolic and growth processes are affected by carbon dioxide
concentrations including photosynthesis and stomatal conductance.
Important physiological processes, photosynthesis, respiration, carbon
allocation and stomatal function are known to be affected by air
pollutants. A wide range in sensitivity of photosynthesis both within
and between species is evident from the literature for the pollutants
SO2, O3, N2O, HF, etc. Some of this variation is clearly due to genetic
factors, but much is in response to differences in environmental
factors, notably light intensity, ambient carbon dioxide levels and
nutrient status. It is assumed that by 2030, the world could be 1-2oC
warmer and sea level 14-25 cm higher than today. Important agricultural
regions in coastal lowlands and deltas could be threatened by flooding,
erosion, and salt intrusion. Small, low-lying island states are
particularly at risk.
Important agricultural regions in coastal low lands
are threatened by flooding, erosion and salt extrusion. Although, the
small, low-lying island states are particularly at risk and vulnerable
to sea level rise. But, if the rise is significantly larger, the result
could be disastrous. With seas rising as much as 1 m, enormous areas of
densely populated. Bangladesh would become uninhabitable. In the
Netherlands for example, it is already a problem in polder areas, which
are below sea level. flashing and rinsing of the polders and canals with
fresh water is necessary, but in dry summers, crop damage is unavoidable
due to insufficient supplies of fresh water. Salt-water intrusion means
that some crops may have to be abandoned or alternative varieties may be
cultivated. Drainage may also be impeded as sea level rises resulting in
loss of yield or ultimately a change in land-use of agricultural area.
Greenhouse gases affect the leaf balance of the earth by absorbing long
wave radiation, which would otherwise escape to space. The worry is that
additions to the atmosphere will cause a rapid global warming and sea
level rise, with adverse consequences. One of the more predictable
consequences of global warming is sea level rise. There are several ways
in which global warming could be expected to affect sea level, i.e. the
thermal expansion of sea water, increased melting of mountain glaciers
and changes in mass of the huge icecaps of Iceland, Greenland and
Antarctica. Changes in the volume of seawater without the addition of
mass (water) result in steric changes in sea level. Sea level is
affected by ocean density, which in turn, affected by water temperature,
as the oceans warm they expand. The hundreds of mountain and glaciers
present in the world in different countries represent less than 1 per
cent of the world's total land ice, the equivalent of 30-60 cm of sea
level, if completely melted.
If greenhouse gas emission continue to increase at
their present rates, the level estimates indicate a global warming of
approximately 0.5oC by 1995-2005; 1.5oC by 2015-2050 and 3oC by
2050-2100 with greater increases evident at higher latitudes. Such
increases appear to be small yet the Earth's temperature has not varied
by more than 1-2oC in the past 10,000 years. In the present century, the
level of carbon dioxide is increasing day by day and the concentration
of CO2 is by far the most important, which affects the greenhouse. The
increase in surface temperature is known as "greenhouse
heating" or the "greenhouse effect". The gases
responsible have become known as "greenhouse gases", and the
concentrations of greenhouse gases in pre-industrial period (1860), of
CO2, methane, N2O and CFCs were 275, 1.1, 0.28, 0.0 (ppm), respectively,
while for the year 2035 will be 475, 2.8, 0.38 and 0.0016 (ppm),
respectively. These figures show a rapid increase in these gases.
What can be done to ameliorate the effect of sea
level rise? For most small, developing countries, the construction of
sea walls, dykes (leaves) and storm surge barriers, such as the Delta
works in the Netherlands and Thames Barrier in the UK, are not feasible
options. Existence of mangroves and other natural features will help
this to intrusion of sea water. Higher levels of urban ozone, the result
of stronger sunlight and warmer temperatures, could worsen respiratory
illnesses. More frequent hot spells could lead to a rise in heat related
deaths. Warmer temperatures could widen the range of disease, carrying
rodents and bugs, such as mosquitoes and ticks, increasing the incidence
of dengue fever, malaria, encephalitis, Lyme disease and other
afflictions. Humans will have a hard enough time adjusting, especially
in poorer countries, but for wildlife, the changes could be devastating.
In near future, nearly 6 billion to 35 billion tons of carbon dioxide
will enter the atmosphere.
A decade ago, the idea that the planet, was warming
up as a result of human activity was largely theoretical. We knew that
since the Industrial Revolution began in the 18th century, factories,
power plants, automobiles and farms have been loading the atmosphere
with heat-trapping gases, including carbon dioxide and methane.
Worldwide temperatures have climbed more than 5oC over the past century
and the 1990's were the hottest decade on record. Similarly, steady
warming has led an impact on no fewer than 420 physical processes and
animal and plant species on all continents. Faced with these hard facts,
scientists no longer doubt that global warming is happening, and almost
nobody questions the fact that humans are at least partly responsible.
There is increasing evidence that rising emissions of
carbon dioxide, methane nitrous oxide and other relatively active gases
will lead to an increase in the average surface temperatures at the
earth. In addition to changes in global temperature, there will be
changes in precipitation. The rate and magnitude of these climatic
changes is much that they could have a significant impact on
agricultural potential in many parts of the world. The nature and extent
of such changes will vary regionally and are dependent upon on the level
of climatic changes in each region, the agriculture and management
practices used at present and the ability of agricultural systems to
adapt to change. The profound effect that weather can have on
agricultural crops can be seen in the common year to year fluctuations
in yields. Frosts, excess rain, high temperatures during ear growth or
grain growth, cool temperature and during grain filling and wet weather
at harvest will all affect yield adversely. Thus, any change in climate,
which alters the frequency intensity, or timing of such events could
have a substantial effect on agriculture. Some of the concentrations of
CO2 releasing in the atmosphere by industrialized countries are as: It
has been reported, that US is by far the biggest polluter on the planet.
With only 4% of the world's population, America produces 25% of its
greenhouse gases (i.e. 186.1 billion tons of CO2, annually). Other major
producers are: European Union (127.8), Russia (68.4), China (57.6),
Japan (31.2), Ukraine (21.7), India (15.5), Canada (14.9), Poland
(14.4), Kazakhstan (10.1), South Africa (8.5), Mexico (7.8), Australia
The most important consequences for agriculture would
stem from a reduction in soil moisture due to higher rates of
transpiration from plants and of evaporation from soil surfaces exposed
to higher temperature. Increases in CO2 in the atmosphere can enhance
plant growth in a number of ways: It can increase the rate of
photosynthesis, leading to greater leaf expansion and a larger canopy
and it can also reduce water losses from plants. Research suggests that
for many species a doubling of CO2 will lead to a 10-15% increase in dry
matter production, providing all other factors remain constant. For
wheat and barley, yield increases of as much as 40% have been suggested.
Majority of plants fall into C3 and C4 groups, according to their method
of assimilating C atoms. C3 plants (such as wheat, barley, rice and
potatoes) responded vigorously to CO2 enhancement. Similarly, C4 plants
(including maize, sorghum, millet and sugarcane) do not. Water is
continuously lost from plants through the process of transpiration.
Water loss due to transpiration, is unavoidable, so that at some point,
most plants will suffer from water stress, when evaporative demands are
greater than water supply. Under such conditions, plants began to wilt,
causing the stomata to close. This restricts water loss, but also limits
CO2 assimilation and thereby plant growth and yield. Higher levels of
atmospheric CO2 will lead to increased efficiency of water use by
reducing transpiration rates.
Except for nuclear war or a collision with an
asteroid, no force has more potential to damage our planets web of life
than air pollution. There is no such thing as normal weather on the
earth. A decade ago, the idea that the planet was warming up as a result
of human activity was largely theoretical. We knew that since the
Industrial Revolution began in the 18th century, factories and power
plants and automobiles and farms have been loading the atmosphere with
heat-trapping gases, including carbon dioxide and methane. A report
issued by the United Nations sponsored Intergovernmental Panel on
'Climate Change' makes plain, the trend towards a warmer world has
Glaciers including the legendary snows of Kilimanjaro
(Africa) are disappearing from mountain tops around the globe. Coral
reefs are dying off as the seas get too warm for comfort. Drought is the
norm of parts of Asia and Africa. El Nino events, which trigger
devastating weather in the eastern Pacific, are most frequent. The
Arctic permafrost is starting to melt. Lakes and rivers in colder areas
are freezing later and thawing earlier each year. Plants and animals are
shifting their ranges poleward and to higher altitudes, and migration
patterns for animals as diverse as polar bears, butterflies and beluga
whales are being disrupted.
MAKING THE CASE THAT OUR CLIMATE IS CHANGING:
From melting glaciers to rising
oceans, the signs are everywhere. Global warming can't be blamcd for any
particular heat wave, drought or deluge, but scientists say a hotter
world will make such extreme weather more frequent-and deadly.
THINNING ICE: Antarctica
— home to these Adelie penguins, is heating up. The annual melt
seasson has increased up to three weeks in 20 years.
Mount Kilimanjaro — has lost 75% of its icecap
since 1912. The ice on Africa's tallest peak could vanish entirely
within 15 years.
Lake Baikal — in eastern Siberia now freezes
for the winter 11 days later than it did a century ago.
Montana — will lose all the glaciers in Glacier
National Park by 2070, if their retreat continues at the current rate.
Venezuelan — mountain tops had six glaciers in
1972. Today only 2 remain.
HOTTER TIMES: Temperatures
sizzled — from Kansas to New England last May, surprising residents
like this Delaware bay with an unusually early heat wave.
Crops withered — and Dallas temperatures topped
38oC for 29 days straight in a Texas hot spell that struck during the
summer of 1998.
India's worst — heat shock in 50 years killed
more than 2,500 people in May 1998.
Cherry Blossoms — in Washington bloom seven
days earlier in the spring than they did in 1970.
Wild weather: Heavy rains — late last year in
England and Wales made for Britain's wettest three-month period on
Fires — due to dry conditions and
record-breaking heat consumed 20% of Samo Island, Greece, last July.
Floods — along the Ohio River in March 1997,
caused 30 deaths and at least $500 million loss in property damage.
Hurricane floyd — brought floods and 210 km/h
winds through the U.S. Atlantic seaboard in September 1999, killing 77
people and leaving thousands homeless. Recently in the month of
September,2004 most of the area in Grenada, Haiti, Cuba, Florida ,
Bhamas, Jamica etc were badly affected by Hurricane Ivan. This brought
devastation of human lives and properties.
Pacific Salmon — populations
fell sharply in 1997 and 1998, when local ocean temperatures rose 3oC.
Polar bears — in Hudson Bay are having fewer
cubs, possibly as a result of earlier spring ice breakup.
Coral reefs — suffer from the loss of algae
that colour and nourish them. The process, called bleaching, is caused
by warmer oceans.
Diseases — like dengue fever are expanding
their reach northward in the U.S.
Butterflies — are relocating to higher
latitudes. The Edith's Checkerspot butterfly of western North America
has moved about 95 km north in 100 years.
Faced with these hard facts, scientists no longer
doubt that change in atmosphere is happening, and almost nobody
questions the fact that humans are at least partly responsible. Already,
humans have increased the concentration of carbon dioxide, the most
abundant heat-trapping gas in the atmosphere, to 30% above
pre-industrial levels-and each year the rate of increase gets faster,
and thus temperatures will keep going up faster each year, and by 2100,
reported by experts that the average temperatures will increase between
1.4oC and 5.8oC — more than 50 per cent higher than predictions of
just a half-decade ago. Even at low end, the changes could be
problematic enough, with storms getting more frequent and intense,
drought more pronounced, coastal areas ever more severely eroded by
rising seas, rainfall scarcer on agricultural land and ecosystems thrown
out of balance. Important agricultural regions in coastal low lands are
threatened by flooding, erosion and salt extrusion. Although, the small,
low-lying is land states are particularly at risk and vulnerable to sea
level rise. But, if the rise is significantly larger, the result could
be disastrous. With seas rising as much as 1 meter (or 3.28 feet),
enormous areas of densely populated land — the Nile Delta, the
Maldives, Bangladesh, coastal Florida and much of Louisiana, would
become uninhabitable. Through such situation prevailing, the agriculture
would be thrown into turmoil.
In Bangladesh, the deeper inundation in the interior
floodplain may lead to a reduction in the areas suitable for cultivating
the dominant strain of paddy rice and necessitate a shift to a lower
yielding variety. It is to be noted that most of land area of the 1,190
small islands constituting the Republic of the Maldives is less than two
meters above sea level. The locations of these small islands are at the
total risk of tidal waves, because, if the phenomenon of tidal waves or
current occur, they will inundate these small islands and thus uprooting
their population. Hundreds of millions of people would have to migrate
out of unlivable regions. Public health could be suffered. Rising seas
would contaminate water supplies with salt. Salt-water intrusion may
also become a problem. As sea level rises, salt water will penetrate
further into estuaries and intrude inland into fresh water and aquifers.
This is already a problem in some small island states. Salt-water
intrusion will also have serious effects on agriculture, reducing the
viability and yields of some crops. Many Pacific islands are dependent
on root crops form a principal part of their diet and crops such as
pulaka and taro are grown in shallow pits, which risk salt
contamination. Salt-water intrusion is not a threat only to small
Saltwater intrusion will also have serious effects on
agriculture, reducing the viability and yields of some crops. Many
Pacific islands are dependent on root crops, form a principal part of
their diet and crops such as taro and pulaka are grown in shallow pits,
which risk salt contamination. Saltwater intrusion is not a threat only
to small islands. In Holland for example, it is already a problem in
polder areas, which are below sea level flashing and rinsing of the
canals with fresh water is necessary, but in dry summers, crop drainage
is unavoidable due to insufficient supplies of fresh water. Saltwater
intrusion means that some crops may have to be abandoned or alternative
varieties may be cultivated. Drainage may also be impeded as sea level
rises resulting in loss of yield or ultimately a change in land — use
of agricultural area. More frequent hot spells could lead to a rise in
heat-related deaths. Warmer temperatures could widen the range of
disease-carrying rodents and bugs such as mosquitoes and ticks,
increasing the incidence of dengue fever, malaria, lyme disease and
other afflictions. Humans will have a hard enough time adjusting,
especially in poorer countries, but for wildlife, the changes could be
devastating. Hundred of millions of people would have to migrate out of
SULPHUR DIOXIDE (SO2):
Since the beginning of this century,
sulphur dioxide from industrial plants has been recognized as an air
pollutant, and as a source of injury to plants. Sulphur dioxide is a
global pollutant, but is more important as a local pollutant since the
mean residence time in the atmosphere is quite short. Its concentration
near big cities is usually between 0.01 and 0.15 ppm by volume, as
against 0.0005 ppm in clean air. Sulphur dioxide particles reflect
sunlight and without this shield, temperatures should go up faster.
Depending on the amount present, leaves may be partially injured or
killed, the symptoms of injury being specific and different from those
produced by other pollutants. The specificity of the damage is confirmed
by the increased sulphur content of the leaves. There is apparently no
decrease in growth or in the photosynthetic rate on concentrations, that
fail to injure the leaf. Alfalfa for instance, grew and photosynthesized
normally when exposed to 0.1 to 0.2 ppm continuously for 45 days. When
fumigated for 4 hrs on 5 successive days with 0.43 to 0.46 ppm, there
were only tracts of leaf injury, and photosynthetic activity was
slightly lowered (to 86-93 % of normal).
The SO2 stress clearly produces a plastic
(irreversible) strain, but no elastic (reversible) strain. Rape and
barley leaves were injured on exposed to 20 ppm SO2, the injury
increasing with the time exposed. An environmental condition that
favours stomatal opening, increases the absorption of SO2 and,
therefore, the injury. On the other hand, 1 ppm of SO2 may itself
increase the degree of stomatal opening throughout the day and night.
PHOTOCHEMICAL OR OXIDANT SMOG: This
kind of gas stress is mainly due to two substances ozone (O3) and
peroxyacetyl nitrate (PAN), although other injurious substances may also
be present. In some respects, the actions of these two substances, are
directly opposite to the action of SO2. They are oxidizing substances
while SO2 is a reducing substance. They injure the lower surface of the
leaf while SO2 injures the upper. Both O3 and PAN may inhibit plant
growth, as well as increase the respiratory rate and decrease the rate
of photosynthesis. Thus, unlike SO2, they can induce both elastic and
plastic strains and can produce both direct and indirect injury. The
effects of O3 are essentially confined to fully expanded leaf tissue,
while PAN is most toxic to younger expanding tissue.
ACID RAIN PHENOMENON: Acid
rain is normally considered to be a by-product of modern atmospheric
pollution. The atmospheric pollution is composed of nitrogen — N
(78%), oxygen — O2 (21%) with the remaining 1% comprises, Ar, CO2, Ne,
He, CH4, Kr, H2, CO, Xe, O3, oxides of S and N and water vapours. These
compounds provided a better understanding of acid rains, produced by
sulphur compounds, the "green effect" and warming of the
atmosphere due to an increase in atmospheric CO2 levels a result of a
worldwide increase the burning of fossil fuels, coal, natural gas and
petroleum oil. These has been a continuous increase in the levels of CO2
in the upper atmosphere resulting in elevated temperatures. It is
estimated that there has an increase of 20% in the CO2 content of the
atmosphere raising the level from 28 parts per million prior to 1900 to
the current level of 380 parts per million. Even in a pure,
uncontaminated world, however, it is likely that the rainfall would be
acidic. Carbonic acid (H2CO3) is formed when carbon dioxide (CO2) is
absorbed by atmospheric water. Nitric acid (HNO3) is created during
thunderstorms and sulphuric acid (H2SO4) is formed from the sulphur
dioxide (SO2) released during volcanic eruptions and forest fires or
from the sulphur (S) emitted by phytoplankton during their seasonal
bloom period. All of these are natural processes, which contribute to
make normal rain acid in the atmosphere.
Current concern over acid rain is not with the
naturally produced variety, but rather with that which results form
modern industrial activity and the acid gases it produces. Considerable
amounts of sulphur dioxide are released into the atmosphere as a
by-product of metal smelting, particularly when non-ferrous ores are
involved. The burning of coal and oil to provide energy for space
heating or to fuel thermal electric power stations also produce sulphur
dioxide. The continuing growth of transportation systems using the
internal combustion engine contributes to acid rain through the release
of oxides of nitrogen (NOx) into the atmosphere. The main sources of
acid rain are to be found in the industrialized areas of the northern
hemisphere. North-eastern North America, Britain and Western Europe have
received most attention, although their output of sulphur dioxide has
been declining since the mid-1970's. Levels of oxides of nitrogen have
not yet experienced significant decline and continue to rise in some
areas. The emission of acid gases from Eastern Europe and the republics
of the former USSR-Russia, Ukraine and Kazakhstan remains high. In Asia,
Japanese industries emit large quantities of sulphur dioxide, while the
industrial areas of China are also major contributors. Acid emissions
remain limited outside of the major industrial nations, but concern has
been expressed over growing levels of air pollution, often associated
with urban automobile exhaust emissions, which may already have provided
a base for acid rain in some Third World countries.
Once the acid gases have been released into the
atmosphere, they are at the mercy of prevailing circulation patterns.
With almost all of the areas currently producing large amounts of acidic
pollution located within the mid-latitude westerly wind belt, emissions
are normally carried eastwards, or perhaps north-eastwards, often for
several hundred kilometers before being redeposit. In this way,
pollutants originating in the US Midwest cause acid rain in Ontario,
Quebec and the New England states. Emissions from the smelters and power
stations of the English Midlands and the Ruhr contribute to the acidity
of precipitation in Scandinavia, and acidity in the Artic originates as
far as 8000 km away to the south in North America and Eurasia. Thus, the
problem of acid rain transcends national boundaries, introducing
political overtones to the problem and creating the need for
international cooperation if a solution is to be found.
The impact of acid rain on the environment was first
recognized in the lakes and rivers of these areas. Reduced pH values
which indicate the rising acidity were accompanied by low levels of
calcium (Ca) and magnesium (Mg), elevated sulphate concentrations and an
increased surface water acidity had adverse effects on fish. In some
cases, the acidity was sufficiently high that mature fish died, but,
more commonly, fish populations began to decline because of the effects
of the increasing acidity on reproduction. Damage to the eggs during
spawning and the inability of the young fry to survive the higher
acidity, particularly during the spring flush, ensured that the older
fish were not replaced as they died. As a result, fish populations in
many rivers and lakes in eastern North America, Britain and Scandinavia
have declined noticeably in the last two to three decades and hundreds
of lakes are now completely devoid of fish and water-borne animals.
There is growing evidence that those areas in which the water bodies
have already succumbed to acidification must also face the effects of
increasing acid rain stress on their forests and soils. The threat is
not universally recognized, however, and there remains a great deal of
controversy over the amount of damage directly attributable to acid
rain. Reduction in forest growth in Sweden, physical damage to trees in
West Germany, and the death of sugar maples in Quebec and Vermont have
all been blamed on the increased acidity of the precipitation in these
areas. Many of the impacts, such as the thinning of annual growth rates,
reduction in biomass and damage to fine root systems, are only apparent
after detailed examination, but others are more directly obvious and
have been described as dieback. This involves the gradual wasting of the
tree inwards from the outermost tips of its branches. The process is
cumulative over several years until the trees dies. The symptoms of
dieback have been recognized in the maple groves and red spruce forests
of north-eastern North America, and across fifteen countries and some
70,000 km of forest in Europe.
The present concern over acid rain is concentrated
mainly on its effect on the natural environment, but acid rain also
contributes to deterioration in the built environment: It attacks
limestone and marble used as building stone, for example. The faceless
statues and crumbling cornices of the world's famous historical palaces,
castles, abbeys, churches, monuments and cathedrals, from the Parthenon
in Greece to the Taj Mehal in India, attest to its power. By attacking
the fabric of these buildings it not only causes physical and economic
damage, but threatens the world's cultural heritage. Acid rain in the
form of aerosols or attached to smoke particles can cause respiratory
problems in humans, as was the case with the infamous London Smog of
1952 and 1962, and caused about 4000 and 700 human deaths, respectively.
There is no evidence that wet deposition is directly damaging to human
health, although in its ability to mobilize metals, from lead (Pb) or
copper (Cu) pipes, for example, it may have important indirect effects.
In Sweden, for instance, some 15,000 lakes have become too acidic to
support sensitive species of animals and plants. It was concluded that
acid rain phenomenon is uncontrollable, because it is a long existing
problem due to industrialization processes all over the world. However,
it needs precaution through human efforts and endeavors.
THINNING OF OZONE LAYER: The
'ozone scare' is a comparatively recent event, but it has gained
worldwide significance owing to its impact on our ecology. Ozone (O3) is
a triatomic form of oxygen. It has three oxygen atoms instead of the
normal two. High concentrations of ozone in the stratosphere are known
as ozone layer, which extends from 15 to 55 kilometers above the earth's
surface. The stratospheric layer contains 90% of atmosphere. Ozone gas
specially the ozone layer is well known nowadays to every one for its
interference to mankind. We know, O3 molecules in the higher altitude of
atmosphere (Stratosphere) absorbs the solar radiation in the ultraviolet
region and prevent them from penetrating earth's surface. In the early
part of this century, the basic photochemical mechanism by which O3 is
maintained in the stratosphere. The role of high concentration of ozone
in the stratosphere is vital as much as it acts as a very effective
filter for absorbing ultra violet rays, which are an integral component
of sunlight. In stratosphere, it acts as a shielding layer to protect us
from the effects of ultra violet rays. Without adequate population of
ozone, there would be an increase in the intensity of ultra violet rays
falling on the surface of the earth resulting in very serious health
hazard to humans in the form of skin cancer. At levels as low as 15 ppm,
it causes headaches, eye irritations coughing chest discomfort.
High concentration of ozone in the trososphere has
been reported to have caused reduction in crop yields by nearly 20-45%
depending on the relative humidity, concentration of ozone and duration
of exposure of the crops to the ozone gas. According to an estimate,
exposure of plants to ozone levels of 0.05 to 0.07 ppm in the
trososphere for 7 hours per day during one season, has caused crop loss
amounting to 5.0 billion dollars in US alone. On an International Scale,
the grain yield losses on account of elevated levels of ozone layer may
run into several billion dollars each year. Destruction of ozone layer
will increase the temperature of the earth. Rise in temperature will
cause damage to the crop production, as the growing of food grain crops
mainly depend on temperature. Thus, increases in temperature of the
planet, has the potential of changing the overall pattern of food
More recently, it has been discovered that
heterogeneous reactions on ice particles can also play an important role
by facilitating the catalytic destruction of O3 by chlorine. These
reactions are now recognized as responsible for the "Ozone
hole" observed during the spring over Antarctica. Day to day use of
Chlorofluorohydrocarbon in different machinery has also been causing
gradual depletion of ozone layer in the stratosphere. Here, we need much
precautions either not to use or to limit the use of this compound so
that ozone layer in the stratosphere is not depleted and we can keep our
earth surface free from penetrating harmful ultraviolet radiation.
Earth is an important, but a tiny component of the
whole universe, with homo sapiens being the most dominant part in it.
Our ecology is surrounded by troposphere. Ozone level in the troposphere
is still sufficiently large to pose a threat to many forms of plant and
animals. Ozone acts as a shielding layer, which protects planet earth
from the harmful effects of the ultraviolet (UV) radiation coming from
the sun. Without adequate population of ozone, there would be an
increase in the intensity of ultra violet rays falling on the surface of
the earth resulting in very serious health hazard to humans in the form
of skin cancer. At levels as low as 15 ppm, it causes headaches, eye
irritations, coughing, chest discomfort. Excessive depletion of ozone
layer due to release of man made chemicals such as chloroflurocarbons
(CFCs), halogens, carbon tetrachloride (CTC) and methyl bromide cause
thinning of ozone layer, which is called ozone hole. The hole is found
over Antarctic and Artic. The size of Ozone Hole, over Antarctic was
double the size of Europe, i.e. 25 million square kilometers in
Ozone allows more ultraviolet radiation to reach the
earth. Increased concentrations of ultraviolet radiation due to ozone
depletion can cause skin cancer, cataract and effect marine life,
plants, materials and different ecosystems. In fact, the ultraviolet
radiation is damaging to almost all of life. In view of the scientific
evidence that man made chemicals such as CFCs, halogen, carbon
tetrachloride and methyl bromide are tremendously destroying the ozone
layer, the international community has decided to phase out the
production and large scale use of these chemicals by signing the Vienna
Convection in 1985 and subsequently the Montreal Protocol in 1987. There
are 172 countries, signatory to the Convection. Stratospheric ozone
blocks ultraviolet light, where all of it is to be brought down to sea
level, the ozone would form a layer only three millimeters thick. In the
1970's it was attacked without restraint by CFC's manufactured at a rate
of nearly a million tons a year as refrigerants, aerosol propellants,
industrial solvents and foam-blowing agents. Rising slowly into the
stratosphere sooner or later, for instance from dumped and rusting
refrigerators, CFC's are broken down by sunlight. Their chlorine then
attacks the ozone by catalysis, so that just one chlorine atom can
destroy tens of thousands of ozone molecules. Largely because of CFC's,
the stratospheric chlorine is now about five times more than before, and
increasing continuously. The globe's average stratospheric ozone level
is thought to have declined by between 4 and 8 per cent. The losses are
particularly marked in Antarctica, where each October of the year sees
the appearance of a 'hole', its area sometimes equaling that of the
United States: ozone is reduced by about 60 per cent overall and by 95
per cent at the center. In the year 2005, there would be very little
ozone in the hole, if present trends being continued. A second, less
transparent hole — ozone levels reduced by 10 per cent or more — now
opens over the Artic at intervals, stretching southwards over much of
Europe and North America.
The threat from CFC's was first explained in the
early 1970's, before discovery of the Antarctic hole. As usual with
pollution crises, the evidence was at first doubted. When the hole was
found it was suggested that seasonal winds were blowing the ozone away.
The Montreal Protocol of 1987, signed at first by twenty-seven
countries, the Protocol called for a 50 per cent cut in the manufacture
of CFC's and halons (which are the other main ozone-destroyers) by 1991.
Later becoming convinced of the inadequacy of this, the signatories
joined by more than fifty further countries, called for phasing out the
use of these chemicals by the end of the century. CFCs and halogens are
far from being the only threats to stratospheric ozone. With their
vapour trails, aircraft cause about a tenth of the ozone depletion, and
could cause much more after the anticipated growth in high-altitude
flights. (In 1990, Britain and France were cheerfully proposing joint
development of a new fleet of supersonic high-altitude aircraft despite
the earlier outcry of environmentalists against similar plans in the
United States.) Nitrogen oxides produced by, for instance, through the
use of nitrogenous fertilizers, destroy may be of another dearth of the
ozone. Methyl bromide, a crop fumigant, destroys perhaps as much again.
Other contributors include methyl chloride: as mentioned earlier, this
is generated copiously when forests, shrubs and grasslands are cleared
by burning. It has been claimed that by ejecting hydrochloric acid, and
volcanoes, send more chlorine to the stratosphere than humans, but this
has been disproved, practically all of the acid is washed out by the
rains accompanying eruptions, and in any case the recent big eruption of
Mount Pinatubo ejected a mere fifty thousand tons of it, an amount
negligible by comparison with the CFCs emitted in the same period. Yet
volcanic emissions, together with industrial pollutants, do help clouds
to form in the stratosphere, these then initiating reactions which sped
up the ravages of the chlorine which humans have put there.
The direct consequences include an estimated
additional 200,000 expected deaths from skin cancer in the United States
alone or (the Environmental Protection Agency has calculated) over
3000,000 by the year 2100, if ozone depletion continues unabated. There
will be many more cases of blindness (100,000 more for each 1 per cent
decline in stratospheric ozone, according to a United Nations panel), a
weakening of the human immune system, and premature aging. Still, the
worst consequences could be indirect ones. Light in the ultraviolet-B
waveband harms living organisms of all main types, on land and in water.
It attacks not only plants, including many trees, but also the
nitrogen-fixing bacteria on which crops rely unless heavily fertilized.
Above all, it may be a grave threat to many zooplankton and
phytoplanktons species. Zooplankton and phytoplankton are at the base of
the oceanic food chains. Phytoplankton are crucial for taking carbon
dioxide from the atmosphere: they remove more of this greenhouse gas
than all other factors combined together.
Overpopulation is often defined as the condition of
having more people than can live on earth in comfort, happiness, and
health and still leave the planet a fit place for future generations. To
most environmentalists, the data suggest that the planet is already
overpopulated. Because of differing concepts of carrying capacity,
however, experts differ widely over what level of population is
considered too high. Some projects that if everyone existed at a minimum
survival level, the earth could support 20 to 48 billion people. This
existence would require that everyone exist only on a diet of grain,
cultivation all arable land, and mining much of the earth's crust of a
depth of 1.6 kilometers. Other analysts believe the earth could support
7 to 12 billion people at a decent standard of living by distributing
the world's land and food supply more equitably and shifting from less
abundant resources (such as lead, tin, uranium, oil, and natural gas) to
more abundant resources (such as aluminum, glass, and various forms of
solar energy). Others opposed to population regulation feel that all
people should have the freedom to have as many children as they want. To
some, population regulation is a violation of their deep religious
beliefs. To others, it is an intrusion into their personal privacy and
freedom. To minorities, population regulation is sometimes seen as a
form of genocide to keep their numbers and power from rising. Proponents
of population regulation point to the fact that we are not providing
adequate basic necessities for one out of five people on Earth today who
don't have the opportunity to be a net economic gain for their country.
They see people overpopulation in MDCs (more developed countries) as
threats to Earth's life support systems for us and other species.
Recently, the Population Crisis Committee compiled a
human suffering index for each of 130 countries based on ten measures of
human welfare. They found a high correlation between the level of human
suffering and the rate of population increase in countries. The 30
countries falling in the extreme human-suffering range — all in Africa
and Asia — averaged a high annual rate of population increase of 2.8%.
The 44 countries with a high human suffering rate — all in Africa,
Asia, and Latin America — also had an average annual population
increase of 2.8%. With the increase in the population on the earth,
there are environmental problems and these problems create things, which
may cause the depletion of ozone layers.
HOW TO WARD OFF DISASTER:
Storing carbon — The atmosphere is not the only
place CO2 an go. With a little ingenuity, it can be wrung out of the air
and set aside for sakekeeping.
Planting trees — They draw CO2 from the air and
give of oxygen. One hectare of forest can sponge up 13.6 tons of CO2 per
year. To purify the atmosphere, tree plantation campaigns should be
initiated against and over again with regular intervals, for tree
plantation campaigns are the steps in the right direction.
Organic and no till agriculture - decaying
organic material in the soil is rich in carbon. Limiting tilling mixing
with oxygen and forming CO2, thus preventing the production of 2.7 tons
of the gas per hectare per year.
Sequestration — greenhouse gases captured from
smokestacks could be injected into abandoned oil and gas wells.
Carbonate rocks — theoretically, CO2 could be
pumped into calcium-based minerals that would bind with the gas and trap
Alternate energy — There are plenty of ways to
generate energy that produce no greenhouse emissions at all.
Wind power — Around the world, windmill use has
been growing 30% a year, now replacing the work of 15 coal-fired power
plants. Europe is the leader, with 70% of all wind power.
Solar power — cells that convert the energy
from sunlight into electricity are a modest, $2.2 billion global
business. Their price is dropping, however, making them more attractive.
Nuclear power — despite well-publicized
problems, nuclear plants still supply about 20% of the power in the US.
Waste and safety issues remain, but the Bush Administration thinks the
technology has a future.
Fuel cells — by combining oxygen and hydrogen,
fuel cells produce electricity, giving off only water. used by the space
programme, they could in a few years be widely emplyed to power
buildings and electric cars.
Conservation — People can use the most
energy-efficient technology already available and make wiser lifestyle
Retrofitting — weatherizing buildings and using
energy-saving lighting and appliances can limit greenhouse emissions.
Decentralized power — localized systems such as
gas cycle turbines can be twice as efficient as getting power from a
Limit sprawl — zoning restrictions can slow
over development. Mass transit and telecommuting can ease traffic jams.
Fuel economy — new SUVs average 8 km/L, 29%
less than the typical car. Will higher gas prices make smaller models
Beyond carbon dioxide — Another important
greenhouse gas is methane, or natural gas. Some simple techniques can
keep it in check too.
Belching cows — cattle let out prodigious
amounts of methane. Already available feeds can reduce the gaseousness,
if more farmers learn to use them.
Rice — flooded paddies produce marshes, which
in turn put out methane. Flooding fields less often and changing
fertilizing methods can limit the release of gas.
Leaky pipelines - natural gas that leaks out of
pipelines flows into the air instead of homes. Plugging holes solves the
PREVENTION OF DAMAGING EFFECTS OF AIR POLLUTION:
In many countries in the world, steps
are being taken to stop the damage to our environment from air
pollution. Scientific groups study the damaging effects on plant, animal
and human life. Legislative bodies write laws to control emissions.
Educators in schools and universities teach students, beginning at very
young ages, about the effects of air pollution. The first step to
solving air pollution is assessment. Researches have investigated
outdoor air pollution and have developed standards for measuring the
type and amount of some serious air pollutants. Scientists must them
determine how much exposure to pollutants is harmful. Once exposure
levels have been set, steps can be undertaken to reduce exposure to air
pollution. These can be accomplished by regulation of man-made pollution
through legislation. Many countries have set controls on pollution
emissions for transportation vehicles and industry. This is usually done
to through a variety of coordinating agencies, which monitor the air and
the environment. Prevention is another key to controlling air pollution.
The regulatory agencies mentioned above play an essential role in
reducing and preventing air pollution in the environment. Adequate
ventilation is also a key to controlling exposure to indoor air
pollution. Home and work environments should be monitored for adequate
air flow and proper exhaust systems installed. One of the most dangerous
air pollutants in cigarette's smoke. Restricting smoking is an important
key to a healthier environment. Legislation to control smoking is in
effect in some locations, but personal exposure should be monitored and
limited wherever possible. Only through the efforts of scientists,
business leader, legislators, and individuals can we reduce the amount
of air pollution on the planet. It is our national responsibility to
make Pakistan a better place to live. We must strive towards abating
existing pollution and upgrading environmental situation. This challenge
must be met by all of us in order to assure that a healthy environment
will exist for ourselves and our children.
Although, the global warming is a man-made problem,
but still there are many ways to decrease the warming phenomenon of the
earth and the environment. In this connection, it is pointed out that
CO2 is the main gas, which increases environment pollution to much
extent. However, one can reduce its concentration through adaptation of
modern technology. It is not an individual problem, primarily collective
behaviour of the citizens are responsible for creating this pollution,
we should remember the saying of Our Prophet Hazrat Muhammad (peace be
upon him), that cleaning is half faith. But in fact, we citizens have
totally forgotten the saying of our Holy Prophet Muhammad (PBUH), and
this is one reason of downfall and uncertainly in the environment. We
should always fear Almighty Allah, who is Omnipotent, Omnipresent and
Omniscient and we must obey His order for our well beings. In this way,
our many worldly problems may be solved by the order of Almighty Allah.