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Malik Ghulam Asghar
B.Sc. hons (Agronomy)
Bahauddin Zakariya University Multan
Environmental change is defined as a change or
disturbance of the environment caused by
human influences or natural ecological
Environmental change can include any number of
1. natural disasters
2. human interference
3. animal interaction.
There are many different factors that affect environment around the
1. Green House Effect
Sea Level Rise
2. Water Pollution
3. Soil Pollution
The greenhouse effect is a process by which thermal
radiation from a planetary surface is absorbed by
atmospheric greenhouse gases, and is re-radiated
in all directions.
Since part of this re-radiation is back towards the
surface and the lower atmosphere, it results in an
elevation of the average surface temperature
above what it would be in the absence of the
A gradual increase in the overall temperature of
the earth's atmosphere generally attributed to
the greenhouse effect caused by increased levels
of carbon dioxide, CFCs, and other pollutants.
Glaciers and ice shelves around the world are melting
The loss of large areas of ice on the surface could
accelerate global warming because less of the sun's
energy would be reflected away from Earth.
An immediate result of melting glaciers would be a rise in
Initially, the rise in sea level would only be an inch or two.
Even a modest rise in sea levels could cause flooding
problems for low-lying coastal areas.
However, if the West Antarctic Ice Sheet were to melt and
collapse into the sea, it would push sea levels up 10
meters (more than 32 feet), and many coastal areas
would completely disappear beneath the ocean
Acid Rain on the Forest Floor
How Acid Rain Harms Trees
How Acid Rain Affects Other Plants
A spring shower in the forest washes leaves and falls
through the trees to the forest floor below.
Some trickles over the ground and runs into streams,
rivers, or lakes, and some of the water soaks into the
That soil may neutralize some or all of the acidity of
the acid rainwater. This ability is called buffering
capacity, and without it, soils become more acidic.
Differences in soil buffering capacity are an
important reason why some areas that receive acid
rain show a lot of damage, while other areas that
receive about the same amount of acid rain do not
appear to be harmed at all.
Acid rain does not usually kill trees directly. Instead, it is more
likely to weaken trees by damaging their leaves, limiting the
nutrients available to them, or exposing them to toxic substances
slowly released from the soil.
At the same time, acid rain causes the release of substances that
are toxic to trees and plants, such as aluminum, into the soil.
Loss of soil nutrients and increase of toxic aluminum may be one
way that acid rain harms trees. Such substances also wash away
in the runoff and are carried into streams, rivers, and lakes.
Trees can be damaged by acid rain even if the soil is well
buffered. Forests in high mountain regions often are exposed to
greater amounts of acid than other forests because they tend to
be surrounded by acidic clouds and fog that are more acidic than
When leaves are frequently bathed in this acid fog, essential
nutrients in their leaves and needles are stripped away.
Acid rain can harm other plants in the same way
it harms trees.
Although damaged by other air pollutants such
as ground level ozone, food crops are not usually
seriously affected because farmers frequently
add fertilizers to the soil to replace nutrients that
have washed away.
They may also add crushed limestone to the soil.
Limestone is an alkaline material and increases
the ability of the soil to act as a buffer against
Acids have a corrosive effect on limestone or marble
buildings or sculptures. It is well established that
either wet or dry deposition of sulfur dioxide
significantly increases the rate of corrosion on
limestone, sandstone, and marble.
sulfur dioxide plus water makes sulfurous acid
SO2 + H2O --> H2SO3
sulfur trioxide plus water makes sulfuric acid
SO3 + H2O --> H2SO4
Climate change is expected to affect air quality
through several pathways, including production
and allergenicity of allergens and increase
regional concentrations of ozone, fine particles,
and dust. Some of these pollutants can directly
cause respiratory disease or exacerbate existing
conditions in susceptible populations, such as
children or the elderly.
Water pollution is the contamination of water
bodies(e.g. lakes, rivers, oceans, aquifers and gro
undwater).Water pollution occurs
when pollutants are directly or indirectly
discharged into water bodies without
adequate treatment to remove harmful
Sewage and Wastewater
Industrial water and water pollution
Nuclear waste – how it is produced
Underground storage leakages
Domestic households, industrial and agricultural
practices produce wastewater that can cause pollution of
many lakes and rivers.
Sewage is the term used for wastewater that often
contains faeces, urine and laundry waste.
There are billions of people on Earth, so treating sewage
is a big priority.
Sewage disposal is a major problem in developing
countries as many people in these areas don’t have access
to sanitary conditions and clean water.
Untreated sewage water in such areas can contaminate
the environment and cause diseases such as diarrhoea.
Sewage in developed countries is carried away from the
home quickly and hygienically through sewage pipes.
Dumping of litter in the sea can cause huge problems. Litter items
such as 6-pack ring packaging can get caught in marine animals and
may result in death. Different items take different lengths of time to
degrade in water:
Cardboard – Takes 2 weeks to degrade.
Newspaper – Takes 6 weeks to degrade.
Photodegradable packaging – Takes 6 weeks to degrade.
Foam – Takes 50 years to degrade.
Styrofoam – Takes 80 years to degrade.
Aluminium – Takes 200 years to degrade.
Plastic packaging – Takes 400 years to degrade.
Glass – It takes so long to degrade that we don’t know the exact time.
Industry is a huge source of water pollution, it produces
pollutants that are extremely harmful to people and the
Many industrial facilities use freshwater to carry away
waste from the plant and into rivers, lakes and oceans.
Pollutants from industrial sources include:
Nuclear waste is produced from industrial, medical and
scientific processes that use radioactive material. Nuclear
waste can have detrimental effects on marine habitats.
Nuclear waste comes from a number of sources:
Operations conducted by nuclear power stations produce
radioactive waste. Nuclear-fuel reprocessing plants in
northern Europe are the biggest sources of man-made
nuclear waste in the surrounding
ocean. Radioactive traces from these plants have been
found as far away as Greenland.
Mining and refining of uranium and thorium are also
causes of marine nuclear waste.
Waste is also produced in the nuclear fuel cycle which is
used in many industrial, medical and scientific processes.
Oceans are polluted by oil on a daily basis from oil spills,
routine shipping, run-offs and dumping.
Oil spills make up about 12% of the oil that enters the ocean.
The rest come from shipping travel, drains and dumping.
An oil spill from a tanker is a severe problem because there is
such a huge quantity of oil being spilt into one place.
Oil spills cause a very localised problem but can be
catastrophic to local marine wildlife such as fish, birds and sea
Oil cannot dissolve in water and forms a thick sludge in the
water. This suffocates fish, gets caught in the feathers of
marine birds stopping them from flying and blocks light from
photosynthetic aquatic plants.
A tank or piping network that has at least 10
percent of its volume underground is known as
an underground storage tank (UST). They often
store substances such as petroleum, that are
harmful to the surrounding environment should
it become contaminated. Many UST’s constructed
before 1980 are made from steel pipes that are
directly exposed to the environment. Over time
the steel corrodes and causes leakages, affecting
surrounding soil and groundwater.
Atmospheric deposition is the pollution of water
caused by air pollution.
In the atmosphere, water particles mix with carbon
dioxide sulphur dioxide and nitrogen oxides, this
forms a weak acid.
Air pollution means that water vapour absorbs more
of these gases and becomes even more acidic.
When it rains the water is polluted with these gases,
this is called acid rain.
When acid rain pollutes marine habitats such as
rivers and lakes, aquatic life is harmed.
An increase in water temperature can result in the death of
many aquatic organisms and disrupt many marine habitats.
For example, a rise in water temperatures causes coral
bleaching of reefs around the world. This is when the
coral expels the microorganisms of which it is dependent on.
This can result in great damage to coral reefs and
subsequently, all the marine life that depends on it.
The rise in the Earth’s water temperature is caused by global
Global warming is a process where the average global
temperature increases due to the greenhouse effect.
The burning of fossil fuel releases greenhouse gasses, such as
carbon dioxide, into the atmosphere.
This causes heat from the sun to get ‘trapped’ in the Earths
atmosphere and consequently the global temperature rises.
Eutrophication is when the environment becomes enriched with
nutrients. This can be a problem in marine habitats such as lakes as
it can cause algal blooms.
Fertilizers are often used in farming, sometimes these fertilisers run-
off into nearby water causing an increase in nutrient levels.
This causes phytoplankton to grow and reproduce more rapidly,
resulting in algal blooms.
This bloom of algae disrupts normal ecosystem functioning and
causes many problems.
The algae may use up all the oxygen in the water, leaving none for
other marine life. This results in the death of many aquatic organisms
such as fish, which need the oxygen in the water to live.
The bloom of algae may also block sunlight from photosynthetic
marine plants under the water surface.
Some algae even produce toxins that are harmful to higher forms of
life. This can cause problems along the food chain and affect any
animal that feeds on them.
Soil pollution is caused by the presence
of xenobiotic (human-made) chemicals or other
alteration in the natural soil environment. It is
typically caused by industrial activity,
agricultural chemicals, or improper disposal
of waste. The most common chemicals involved
are petroleum hydrocarbons, polynuclear
aromatic hydrocarbons (such as naphthalene
andbenzo (a) pyrene), solvents, pesticides, lead,
and other heavy metals. Contamination is
correlated with the degree of
industrialization and intensity of chemical usage
Soil pollution can be caused by the following
Genetically modified plants
Landfill and illegal dumping
Pesticides, herbicides and fertilizers
Mining and other industries
Oil and fuel dumping
Disposal of coal ash
Historical deposition of coal ash used for residential, commercial, and
industrial heating, as well as for industrial processes such as ore
smelting, were a common source of contamination in areas that were
industrialized before about 1960.
Coal naturally concentrates lead and zinc during its formation, as
well as other heavy metals to a lesser degree.
When the coal is burned, most of these metals become concentrated
in the ash (the principal exception being mercury).
Coal ash and slag may contain sufficient lead to qualify as a
"characteristic hazardous waste", defined in the USA as containing
more than 5 mg/L of extractable lead using the TCLP procedure.
In addition to lead, coal ash typically contains variable but significant
concentrations of polynuclear aromatic hydrocarbons (PAHs; e.g.,
benzo(a)anthracene, benzo(b)fluoranthene, benzo(k)fluoranthene,
benzo(a)pyrene, indeno(cd)pyrene, phenanthrene, anthracene, and
Treated sewage sludge, known in the industry as biosolids, has
become controversial as a fertilizer to the land. As it is the
byproduct of sewage treatment, it generally contains more
contaminants such as organisms, pesticides, and heavy metals
than other soil.
In the European Union, the Urban Waste Water Treatment
Directive allows sewage sludge to be sprayed onto land.
The volume is expected to double to 185,000 tons of dry solids
This has good agricultural properties due to the
high nitrogen and phosphate content.
In 1990/1991, 13% wet weight was sprayed onto 0.13% of the
land; however, this is expected to rise 15 fold by 2005.
Pesticide is a substance or mixture of substances used to kill a
A pesticide may be a chemical substance, biological agent (such as a
virus or bacteria), antimicrobial, disinfectant or device used against
any pest. Pests include insects, plant pathogens, weeds, mollusks,
birds, mammals, fish, nematodes (roundworms) and microbes that
compete with humans for food, destroy property, spread or are a
vector for disease or cause a nuisance.
Although there are benefits to the use of pesticides, there are also
drawbacks, such as potential toxicity to humans and other organisms.
Herbicides are used to kill weeds, especially on pavements and
One group derived from trinitrotoluene (2:4 D and 2:4:5 T) have the
impurity dioxin, which is very toxic and causes fatality even in low
Effect on Growth of Plants
Health effects due to Soil Pollution
The ecological balance of any system gets affected due to
the widespread contamination of the soil.
Most plants are unable to adapt when the chemistry of
the soil changes so radically in a short period of time.
Fungi and bacteria found in the soil that bind it together
begin to decline, which creates an additional problem of
The fertility slowly diminishes, making land unsuitable
for agriculture and any local vegetation to survive.
The soil pollution causes large tracts of land to become
hazardous to health.
Unlike deserts, which are suitable for its native
vegetation, such land cannot support most forms of life.
Contaminated or polluted soil directly affects human health
through direct contact with soil or via inhalation of soil
contaminants which have vaporized; potentially greater threats
are posed by the infiltration of soil contamination into
groundwater aquifers used for human consumption, sometimes
in areas apparently far removed from any apparent source of
above ground contamination.
Chronic exposure to chromium, lead and other metals,
petroleum, solvents, and many pesticide and herbicide
formulations can be carcinogenic, can cause congenital
disorders, or can cause other chronic health conditions.
Industrial or man-made concentrations of naturally occurring
substances, such as nitrate and ammonia associated with
livestock manure from agricultural operations, have also been
identified as health hazards in soil and groundwater.
Chronic exposure to benzene at sufficient concentrations is
known to be associated with higher incidence of leukemia.
Mercury and cyclodienes are known to induce higher incidences
of kidney damage, some irreversible.
PCBs and cyclodienes are linked to liver toxicity.
Organophosphates and carbomates can induce a chain of
responses leading to neuromuscular blockage.
Many chlorinated solvents induce liver changes, kidney changes
and depression of the central nervous system.
There is an entire spectrum of further health effects such as
headache, nausea, fatigue, eye irritation and skin rash for the
above cited and other chemicals.
At sufficient dosages a large number of soil contaminants can
cause death by exposure via direct contact, inhalation or
ingestion of contaminants in groundwater contaminated
Loss of habitat
Drives climate change
Deprives the forest
Speed and severity of global warming.
Deforestation has many negative effects on
the environment. The most dramatic impact
is a loss of habitat for millions of species.
Seventy percent of Earth’s land animals and
plants live in forests, and many cannot
survive the deforestation that destroys their
Deforestation also drives climate change.
Forest soils are moist, but without protection
from sun-blocking tree cover they quickly dry
out. Trees also help perpetuate the water
cycle by returning water vapor back into the
atmosphere. Without trees to fill these roles,
many former forest lands can quickly become
Removing trees deprives the forest of
portions of its canopy, which blocks the sun’s
rays during the day and holds in heat at night.
This disruption leads to more extreme
temperatures swings that can be harmful to
plants and animals.
Trees also play a critical role in absorbing the
greenhouse gases that fuel global warming.
Fewer forests means larger amounts of
greenhouse gases entering the atmosphere—
and increased speed and severity of global
A carbon sink is a natural or artificial reservoir that
accumulates and stores some carbon-containing
chemical compound for an indefinite period. The
process by which carbon sinks remove carbon
dioxide (CO2) from the atmosphere is known
as carbon sequestration.
Forests as a carbon sink are often overlooked as a major
source of carbon removal from the atmosphere, a process
known as carbon sequestration.
Conversely , deforestation, whether removal of forests by
logging or burning, has been a major contribution to
atmospheric carbon addition.
There are two main reasons for land use conversion
by deforestation; ranching and agriculture.
These conversions are done in an attempt to produce short
term economic benefit by forcing immediate environmental
Cattle ranching is one of the leading causes of deforestation.
Afforestation is the establishment of a
forest or stand of trees in an area where there
was no forest.
Reforestation is the reestablishment of
forest cover, either naturally (by natural
seeding, coppice, or root suckers) or artificially
(by direct seeding or planting).
Many governments and non-governmental
organizations directly engage in programs
of afforestation to create forests, increase carbon
capture and sequestration, and help to
anthropogenically improve biodiversity
In a natural forest or woodland, the trees are heterogeneous.
Owing to the sensitivity to over usage and slow growths, these
forests cannot be used continuously for commercial purposes
like wood products.
The process of planting trees in empty lands helps promote the
fast propagation of specific types of trees for the wood industry.
With the increasing demand for wood fuels and building
materials, this process helps to meet these demands without
cutting down the natural forests.
Afforestation ensures trees and plants that hold the soil in
these sensitive areas remain protected.
Many countries have introduced the practice of planting trees along
with agricultural crops in croplands. The benefits of this practice,
which is called agroforestry, are:
It provides a supply of timber, fruit, and fodder for cattle apart
from crop production
It prevents soil erosion
It enables better retention of water
It shields crops from excessive wind and sun damage
In terms of the environmental benefits, planting trees is always
beneficial whether it takes place in a barren land or is used as a
method to regenerate a depleted forest.
Trees help check atmospheric carbon dioxide; large scale
afforestation can curb the problems caused due to burning of
fossil fuels, industrialization and so forth.