MEV 011: Unit 03 - Environmental Issues
UNIT 3 -
ENVIRONMENTAL ISSUES
3.1
Introduction
Many global
and local environmental problems had been identified by the United Nations
Environment Programme (UNEP) that poses a big challenge for national and
international organizations. For example, ozone layer depletion, photochemical
pollution in the air, desertification, water pollution, microplastics, soil
erosion and, municipal and industrial wastewater, acid rain events, population
growth and urbanization, deforestation and biodiversity loss, climate change
are some environmental issues that threaten our natural resources and human
health.
This unit
deals with environmental issues at local, regional, and global levels and
rising environmental problems like global warming, climate change, ozone
depletion, and acid rain. The students would be able to learn about major
environmental issues as well as pollution problems. After studying this unit,
they will understand water scarcity, degradation of natural resources, and the
reasons responsible for them, like deforestation and soil erosion. The social
problems like urban sprawl, traffic congestion, and socio-economic status are
also discussed in this unit.
3.2
Objectives
After
reading this unit, you should be able to:
•
identify environmental issues at local, regional, and
global levels;
•
discuss rising environmental problems like global
warming, climate change, ozone depletion, and acid rain;
•
discuss water scarcity, degradation of natural
resources, and the reasons responsible for them, like deforestation and soil
erosion; and
•
describe social problems like urban sprawl, traffic
congestion etc.
3.3
Global, Regional and Local Environmental Issues
Global environmental
issues are the environmental problems that affect the whole world,
and the co-operation and participation of all countries are required to
overcome these issues. For example, global warming, climate change, ozone
depletion, and biodiversity conservation are such kind of global environmental
issues.
National
issues are the problems of a country that have to be addressed by
the nation itself.
1. Land use
pattern and degradation of soil: Agriculture is the major economy
of India and provides a push to the GDP growth rate. However, due to soil
degradation, the agricultural share in GDP is declining in the country. The
main reasons behind soil degradation are extensive agriculture and excessive
use of fertilizers and pesticides in the agricultural fields.
2. Water crisis: It is
predicted that about 3.5 billion people will face the problem of water crisis
by the year 2025. This problem is more pronounced in India because of
unsustainable water management systems (World Bank, 2005).
3. Air
pollution: In India, the problem of air pollution persists in urban as
well as rural areas. Nitrogen Oxide (NOx), Suspended Particulate Matter (SPM),
Carbon Monoxide (CO), Sulphur Dioxide (SO2), Carbon Dioxide (CO2) are the major
pollutants observed.
4. Waste
disposal: An increasing population and urbanization lead to the
production of a huge amount of municipal and hazardous waste. The management of
waste is a big task in front of the Indian government. There are many types of
waste, such as physical (paper, rags, plastic, glasses, metals, etc.), chemical
waste, and other biological substances.
Local
environmental issues include those problems which affect a particular
local area. According to the Ministry of Information and Broadcasting (2004),
the local environmental problems common in India are:
•
Deforestation
•
Pollution
•
Desertification
•
Degradation of common property
•
Resources like pastures, villageponds, and tanks,
wetlands, etc.
•
Freshwater and marine ecosystems
3.4
Degradation of Natural Resources
Natural
resource degradation refers to the loss of the environment and biodiversity in
an area. Nowadays, degradation occurs rapidly, and environmental resources are
not getting much time to regenerate themselves. The main reason behind this
degradation is the increasing demands of the rising population
3.4.1
Factors Responsible for the Depletion of Natural Resource
1.
Overpopulation and over-exploitation: The
population of the world is about 7 billion and is increasing continuously. To
fulfill the needs of such a huge number of people, natural resources are
over-exploited. Resources are required to support industrialization and
urbanization. As a result, it disturbs the environment and reduces its
regenerative capacity.
2.
Poor farming: Our farming practices also affect
soil quality. For example, poor irrigation and poor management of soil along
with heavy equipment disturb the soil structure. Moreover, the excessive use of
pesticides and herbicides kills many beneficial microbes that help maintain
soil nutrients.
3.
Deforestation: From 1990 to 2016, the net loss of
forest cover was reported as 1.3 million km2 (World Bank, 2016).
Forests are cleared mainly for agricultural land to fulfill the needs of the
growing population.
4.
Pollution: Increasing population and
lifestyle has added many pollutants to the environment such as harmful gases,
plastic, sewage, and many toxic chemicals contaminating our air, land, water, and
soil.
3.4.2
Effects of Resource Degradation
The
depletion of natural resources by human beings can cause many drastic impacts
on the environment and wildlife. Some of these are discussed below:
1. Depletion
of water resources: The poor irrigation practices, as well as pollution,
will cause water shortage, which further leads to drought and food insecurity.
2. Forest
loss: About 7.3 million hectares of forest cover are destroyed
each year (National Geographic Society, 2016). Previous studies indicate that
deforestation has also increased the amount of greenhouse gases in the
atmosphere.
3. Species
Extinction: Due to over-exploitation of resources and forest
degradation, many useful and rare species of plants and animals will get
extinct.
4. Depletion
of mineral resources: To complete the needs of a growing population, many
useful minerals like copper, zinc, and phosphorus will get depleted due to
over-exploitation.
3.4.3
Solutions to Control Resource Degradation
Our
resources are required for development as well as to fulfill the basic needs. Therefore,
some steps need to be taken to stop the degradation of our resources.
1. Reducing
deforestation: Some initiatives should be taken to conserve the forest and
wildlife habitats. For example, REDD (Reducing Emissions from Deforestation and
Forest Degradation) formulated by the World Bank is aimed to check
deforestation.
2. Use of
alternate resources: We should rely more on renewable resources such as
wind power and solar energy to minimize the pressure on nonrenewable resources.
3. Reducing
consumption of minerals: As minerals cannot be replenished very fast in nature
so their use should be minimized, and over-exploitation should be reduced.
4. Awareness: People
should know about the depletion of our natural resources, and it could be done
through awareness programs. The public should be encouraged to reduce their use
and dependency on resources and conservation of resources.
3.5
Pollution of Air, Water and Soil
Pollution
is any undesirable change in the physical, chemical, and biological properties
of air, water, or soil that adversely affect the health of plants and animals.
Pollutants are substances that cause pollution and are added to the environment
through human activities. These pollutants can accumulate in water, soil, and
air and negatively affects their quality.
3.5.1
Air Pollution
The foreign
substances that adversely affect air quality are known as air pollutants. Some
of the air pollutants are:
•
oxides of carbon (CO and CO2)
•
oxides of sulphur (SO2 and SO3)
•
oxides of nitrogen (NO, NO2 and N2O)
•
volatile organic compounds (VOCs) such as hydrocarbons
(propane, methane, etc.), mainly released from the burning of fuels
•
chlorofluorocarbons
•
suspended particulate matter (PM10 and PM2.5)
including dust, smoke, soot
•
hazardous pollutants like carbon tetrachloride and
benzene
•
radioactive substances
•
other microscopic droplets
Corrective
actions to control air pollution
•
Use of unleaded petrol to prevent the release of lead
in the air.
•
Special filters to be adopted by the industries and
factories to reduce gaseous emissions.
•
Alternative energy sources (hydropower and wind
energy) should be preferred to minimize the use of fossil fuels.
•
Strict laws to prevent the release of CFCs and
nitrogen oxides into the air
•
Electric vehicles should be used more to reduce the
emissions of CO2 and CO into the atmosphere.
•
Public transport systems should be made more efficient
to reduce traffic congestion.
3.5.2
Water Pollution
The
pollution caused by the excess concentration of some physical, chemical, or biological
substances alters the quality of water and makes it unfit for drinking and other
purposes.
Sources of water pollution:
•
Biological pollutants are mainly microbes like
bacteria, viruses, and protozoa, which cause water-borne diseases. They can reach
to surface and groundwater and cause major infections like typhoid, cholera,
hepatitis, etc. Environmental Issues
•
Chemical pollutants include fertilizers, pesticides,
and heavy metals (lead, mercury, cadmium, chromium, etc.)
•
Persistent organic pollutants (POPs) are the toxic
chemicals released from pesticides and other industrial processes. For example,
DDT, Polychlorinated biphenyls (PCBs) and aldrin, etc.
Corrective
actions to control water pollution
•
Community education to teach them about the recycling
of substances.
•
Provision of containers to recycle materials such as
paper and glass.
•
Enforcement of large fines for the illegal dumping
into rivers.
•
Proper removal of sewage from settlement by the
municipality.
•
Strict laws to prevent the dumping of wastes into
seas, rivers, dams, and streams.
•
Large penalties and strict laws for oil companies when
oil tankers sink, leak, or spill oil.
•
Encourage people to use organic fertilizers and
manure.
•
Encourage farmers to adopt integrated pest management.
3.5.3
Soil Pollution
The
presence of some harmful particles in the soil, which reduces its fertility, is
known as soil pollution. Some kinds of solid and liquid waste and toxic
chemicals affect soil quality and percolate up to groundwater.
Sources of soil pollution
•
Industrial and chemical waste
•
Municipal and solid waste
•
Open defecation
•
Leakage from storage containers
•
Open dumping
•
Insecticides such organophosphates and carbamates etc.
•
Fungicides like Capton and Sovran etc.
Corrective
actions to reduce soil pollution
•
Education and awareness among people to follow the
principle of reducing, reuse and recycle
•
Enforcement of legal actions and strict fines for
prevention of dumping in unauthorized areas.
•
Afforestation programs and use of indigenous trees.
•
Crop rotation in fields by farmers.
•
Provision of settlements with proper waste management.
•
Provision of dustbins in towns and cities by local
government
•
Formation of action committees to clean up polluted
areas.
3.6
Persistent Organic Pollutants
POPs are
the chemicals that can persist in the environment for longer (many years) and
magnify and accumulate in the organisms, and causes adverse health impacts on
human health. One can get exposed to these chemicals by eating contaminated
food, breathing in polluted air, and other exposed areas or accidents. They are
easily found in items like surfactants and flame retardants, added to improve
their characteristics.
3.6.1
Characteristics of POPs
•
Stays intact for longer periods
•
Get widely distributed in the environment through air,
water, and soil
•
Can travel to far distances, away from original
resources
•
Not soluble in water
•
Readily absorbed in fatty tissues and can get
magnified up to 70,000 times
•
Found in higher concentration at the top level of the
food chain
•
Toxic to wildlife and humans
For
example, organochlorine pesticides like DDT, polycyclic aromatic hydrocarbons
(PAHs), organometallic compounds like tributyltin (TBT), chemicals from
industries such as PCBs and other industrial by-products like dibenzofurans
(PCDF), and polychlorinated dibenzo-p-dioxins (PCDD) mostly referred to as
‘dioxins’
3.7
Water Scarcity
Water
covers about 70% of the earth’s surface. However, the freshwater is only 3%, and
two-third is present in the frozen form that is unavailable for our use.
Water
scarcity occurs when water is not available enough to meet the demands due to physical
or shortage of water or infrastructure failure to meet the water supply for people’s
regular water demands. Scarcity of water is an issue that has affected every
continent of the world. The main reason behind this scarcity is overuse and
wastage of water.
Water is
enough to sustain seven billion people on planet earth. However, it is unevenly
distributed, and a lot of water gets wasted, overexploited, and not managed
sustainably.
3.7.1
Causes of Water Scarcity
There are
many factors responsible for water scarcity in the world. Some important causes
of water scarcity are discussed below:
•
Pollution: The use of pesticides and
fertilizers in the field, as well as the discharge of wastewater from the
industries, pollutes the water bodies. Sometimes the pollution also reaches the
groundwater and makes it unfit for various uses.
•
Agriculture: Around 70% of the world’s
freshwater is used up in agriculture, and 60% of it get wasted due to
inefficient application and inappropriate irrigation system and cultivation of
thirsty crops. It creates pressure on our water resources, and the river,
lakes, and underground aquifers are getting dried.
•
Population growth: The human population has
grown twice in the last 50 years. This fast-growing population, along with
industrialization and urbanization, has created stress on water resources.
Nowadays, 41% of the population lives in water-stressed river basins globally.
Actions to
be taken
Individual
countries have to take immediate steps to avoid critical water stress in the
near future. Water needs to be treated as a scarce resource. All the countries
should follow integrated water resources management by managing the available
water resources according to the number of people sustainably.
3.8
Soil Erosion and Land Degradation
Soil is an
essential component of land, and it takes thousands of years for its formation.
The top layer of soil is equipped with many nutrients for crop growth and is
also at a higher risk of wind and water erosion. When this top fertile layer is
removed due to any agent, it is known as soil erosion. Currently, the global
rate of soil erosion is higher than its formation.
Soil
erosion is a major problem in regions with a higher population, agricultural
land, and urbanization. The watersheds of India, Indonesia, the Philippines, and
many more have the highest risk of soil erosion. The erosion of soil hinders
plant growth, affects agricultural production, recreation, and water quality.
It occurs naturally on land and is a key reason for land degradation.
3.8.1
Factors Responsible for Soil Degradation
Soil
erosion occurs when soil is exposed to high winds or raindrops. The other
sources of erosion are discussed below:
1. Rainfall: Heavy
rainfalls disperses the material of soil and carry it along with runoff. It
carries away silt, organic matter of soil, and finer particles also and
sometimes large particles are also affected depending on the severity of
rainfall.
2. Agricultural
activities: Unsustainable agriculture and intensive farming affect
Environmental Issues soil structure and organic matter content, making it more
vulnerable to erosion. For example, the tillage of lands breaks the soil
structure and contributes to soil erosion.
3. Vegetation
cover: The land areas with less natural vegetation cover are more
susceptible to soil erosion as flora protects soil structure.
4. Wind: High
blowing winds facilitate erosion, especially when it is loose in structure. The
sandy or lighter soils are more affected as they can be easily blown away.
5. The land’s
slope: The land with a higher slope is more vulnerable to rain erosion
as water moves faster down the hill, and the water percolation rate is also
very low.
3.8.2
Impacts of Soil Erosion
The process
of soil erosion causes a lot of land degradation and other impacts, which are
discussed below:
1. Affects
people’s livelihood: About 52% of the agricultural land is severely
affected by soil erosion due to removing trees from the landscape and
increasing food insecurity.
2. Climate
mitigation: The annual sequestration rate of CO2 by the world’s forests
is about 2.4 billion tonnes. The destruction of forests emits more CO2 into the
air and annual emission of 4.3–5.5 GtCO2eq/yr. Hence conservation of soil and forests is essential
to mitigate climate change.
3. Biodiversity
loss: More than 80% of global terrestrial biodiversity is present in
the forests. The survival of many species is threatened due to forest
degradation and erosion.
4. Economic
loss: The economic loss faced by the world due to soil erosion is
around eight billion dollars. It is due to reduced fertility of the soil, less
crop production, and overuse of water. For example, in Indonesia, soil erosion
is a reason for 2 percent loss in the agricultural gross domestic product
(GDP).
3.8.3 Solutions to
Prevent Soil Erosion
1. Good
agriculture practices: Some soil friendly practices should be followed in
agriculture, such as:
•
Terrace farming in hilly areas to prevent water and
soil loss
•
Intercropping system with plantation of two crops
together, for example,
•
soybean or maize crop between oil-palm trees
•
Alternate growth of shallow-rooted and deep-rooted
crops to improve soil
•
structure
•
Agroforestry system
•
Application of organic manure to improve nutrients in
the soil
2. Sustainable
land management practices with incentives: The methods to prevent soil
erosion should be adopted by farmers, and they should be supported financially
by the government and banks. The approximate cost of anti-erosion methods is
about 500 dollars per hectare, higher for a small farmer.
3. Rehabilitation
and prevention: The land which is already damaged should be
rehabilitated, and preventive measures should be adopted to stop soil erosion.
3.9
Deforestation
Deforestation
is converting forested land to non-forest use, such as agricultural land and
for construction purposes. It leads to the forests’ degradation, and they lose
their capacity to provide essential goods and services.
Deforestation
and the degradation of the forests are the biggest threat nowadays. Since the
1960s, more than half of the tropical forests have been destroyed globally and
affected the livelihood of about 1.6 billion people.
3.9.1
Causes of Deforestation
The main
reason behind deforestation is expanding and extensive agriculture with poorly
panned infrastructure and unsustainable practices. Moreover, illegal logging is
responsible for major forest degradation. Deforestation has alarmingly
devastated the tropical rain forests, and these are home to a lot of
biodiversity in the world. For example, in the Amazon rainforest, in the last
50 years, about 17% of the forest area has been lost due to forest conversion
for cattle ranching.
Another
major cause of deforestation is forest fires. The fires are a natural element,
but when they are at the wrong place and at the wrong time, they can cause huge
destruction. Millions of acres of forested land are degraded by forest fires
annually. These fires destroy the forests, threaten biodiversity, open the
forest for invasive species, and affect soil fertility.
3.9.2 Impacts of
Deforestation
•
Increased greenhouse gas emissions (GHGs): The
forests act as carbon sinks and mitigate climate change. The tropical forests
can sequester 228 to 247 gigatons carbon, which equals seven times the annual
anthropogenic emissions. Although deforestation and degradation of forests are
alone responsible for 15% emissions of GHGs.
•
Disruption in the water cycle: The trees
maintain a balance between land and atmosphere. Due to deforestation, the
precipitation and water cycles become unregulated and disturbed.
•
Soil erosion: Large trees hold the soil firmly,
and after deforestation, the soil easily gets exposed and eroded. The fertility
of soil also gets reduced due to erosion.
•
Affects livelihoods of people: About 750
million lives in and around forests, and around 1.25 billion people in the
world are dependent on the forest for their shelter, food, water, and
livelihood. Deforestation affects these people with devastating consequences on
their lives.
3.9.3
Solutions to Reduce Deforestation - Many solutions are available to
control and minimize deforestation as described here:
•
Conservation agriculture: The
expansion of agriculture should be performed responsibly, along with the
conservation of forests. The organizations and governments should remain
committed to forest conservation along with agriculture.
•
Alternate and sustainable energy sources: Humans are
relying on forests for fuel for thousands of years ago. To reduce our reliance
on the forest, we should go for energy from waste, scraps, and residues.
•
Creation and management of conservation areas: Many forests
are declared protected areas, but they are not managed properly. The funds can
be collected from the public and private sectors to conserve these natural
resources.
•
Forest landscape restoration (FLR): The FLR
can come out as an important solution for reversing the impacts of forest
degradation and deforestation. It will also help regain the social, climatic,
ecological, and economic benefits from the forests.
FLR
includes multiple programs like erosion control, agroforestry, and regeneration
of the natural forest. It also monitors the possible causes responsible for
forest loss. It also provides knowledge about sustainable agricultural methods
to the farming communities living in and nearby forest areas.
3.10
Emergence of Air, Water and Soil-borne Diseases
3.10.1
Airborne Diseases
Airborne
diseases are those that can infect a person only by breathing or inhaling some
pollutants or particles. The infection can spread through sneezing, cough, or
talking. Some bacteria and viruses can stay in the air and on surfaces for many
hours. Sometimes, they contact an infected person or from droplets in the air,
such as Coronavirus disease-19 (COVID-19). The other common examples of
air-borne illnesses are the common cold, influenza, mumps, measles, chickenpox,
whooping cough, diphtheria, etc.
Symptoms of
airborne diseases
Each
disease has its particular symptoms. However, the major symptoms among which
one or more is common in airborne diseases are sneezing, congestion, running
nose, coughing, swollen glands, sore throat, fever, loss of appetite and fatigue
etc.
Treatment for common airborne
diseases: Some common treatment methods can be applicable for airborne
diseases. These are:
·
Plenty of fluids intake and rest
·
Antiviral drugs in case of common flu
·
Use of antibiotics and hospitalization if needed
·
Special care on detection of a specific illness
3.10.2
Waterborne Diseases
These
diseases are caused by various micro-organisms present in water or drinking
contaminated water such as diarrhea, cholera, typhoid, hepatitis, dysentery,
meningitis, or other gastrointestinal problems. The water can get contaminated
through various sources like industrial effluents, household waste, human and
animal waste, untreated sewage, and other chemical effluents. The water can also
be contaminated with bacteria like E. coli and many viruses such as hepatitis.
An outbreak
of disease can occur mostly after severe rainfall or flood as they boost the
growth of bacteria and viruses. Climate change and extreme weather events also
support the spread of many microbes. The disease can spread from any water
source. However, its surveillance and diagnosis are required to control disease
spread.
Symptoms: Some
common symptoms related to the waterborne disease are diarrhea and vomiting,
sometimes skin, ear, eye, and respiratory infections are also associated
depending on the specific disease.
Prevention
of waterborne diseases: Some precautionary measures can prevent the spread of
waterborne illnesses. These are discussed below:
·
Water should be purified at the household level to
make it potable
·
Water should be clean and dirt-free, visibly
·
Where the risk of infection is high, bathing water
should be used by adding some antiseptic liquid.
·
Hand hygiene should be followed while eating, cooking,
and using toilets
·
Food should be washed thoroughly
·
Vaccinations should be followed for diseases such as
polio, typhoid, and hepatitis A, etc.
3.10.3
Soil-borne Diseases
The
organisms responsible for soil-borne diseases can be found in gardens,
agricultural fields, and warm areas where the climate is favourable for their
growth. The organisms live in the soil and infect human beings as their host.
These diseases sometimes are infectious, and one person can get infected by
another person. Some examples of soil-borne diseases include amoebiasis,
ascariasis, hookworm, enterobiasis, Q fever, lime disease, giardiasis,
salmonellosis, shigellosis, tetanus, etc.
Common
symptoms: The cause of infection can be direct ingestion of
contaminated food from soil, direct inoculation, or inhalation. The symptoms of
soil-borne infections are wounds, skin problems, gastrointestinal infections,
and respiratory tract diseases. For example, tetanus, botulism, and anthrax. Some
fungal infections from the soil are life-threatening, especially in people with
a weak immunity.
Prevention and treatment of
soil-borne infections: Some preventive and treatment measures can minimize
the spread of soil-borne diseases. These include:
·
Prompt diagnosis of the disease
·
Intensive care and support to patients
·
Application of antitoxin and antibiotic therapies
·
Investigation about the source of infection to prevent
its further spread
·
Public health measures in disease-prone areas, like
after a flood or heavy rainfall and other disasters.
3.11
Global Warming Gases
Greenhouse
gases (GHGs) or global warming gases absorb heat in the atmosphere and trap the
solar radiations, which causes warming of the earth. The major GHGs are
Carbon-dioxide (CO2), methane (CH4), nitrous oxide (N2O), and some fluorinated
gases like chlorofluorocarbons (CFCs), Sulfur hexafluoride, and
hydrochlorofluorocarbons (HCFCs).
·
Carbon-dioxide: The sources of CO2 in the
atmosphere are from the open burning of solid waste and fossil fuels along with
trees other biological and agricultural waste.
·
Methane: CH4 is naturally released from the
decomposition of organic waste in landfills, from livestock, and during the
production of fossil fuels like coal, oil, and natural gas.
·
Nitrous oxide: This gas is emitted through
industrial and agricultural activities like excess use of fertilizers, burning
of fossil fuels, and wastewater treatment.
·
Fluorinated gases are mainly emitted from
industrial sources as they are used as coolants and propellants.
According
to USEPA (2020) report, the total emissions of GHGs in 2018 were 6,677 Million
Metric Tons of CO2 equivalent. Two main properties determine the power of gas
to cause the greenhouse effect. These are:
•
Global warming potential (GWP): Various
GHGs have different heattrapping capacities known as GWP. It measures the
radiative impact of each molecule of gas over a specified time. For example,
N2O is 264 times more potent than carbon dioxide for a 100-year timescale.
•
Atmospheric lifetime: It
measures the lifetime of gas in the atmosphere before removal through any
chemical reaction.
A
gas with more GWP and more life span in the atmosphere will cause more earth warming.
Table below depicts the GWP and atmospheric life span of major GHGs.
|
GHG |
Chemical formula |
GWP (100-year time horizon) |
Atmospheric Lifetime (in years) |
|
Carbon Dioxide |
CO2 |
1 |
100 |
|
Methane |
CH4 |
25 |
12 |
|
Nitrous Oxide |
N2O |
298 |
114 |
|
Chlorofluorocarbon-12
(CFC-12) |
CCl2F2 |
10,900 |
100 |
3.12 Climate Change
Climate
change is the rising issue of the present time. It addresses the complex shifts
in the weather of planet earth and climate systems. It includes global warming
and other extreme weather events, rising sea levels, extinction of species and
shift in wildlife populations, habitat destruction, and many other impacts.
These shifts in weather threaten food production and the rising sea level
increases the risk of flooding.
The earth’s
temperature is rising nearly twice the rate as it was 50 years ago. The GHGs
emitted by human activities are mainly blamed for this continuous warming of
the earth. Although GHGs are essential as they keep the earth liveable by
stopping some radiations from reflecting back. However, due to rapid industrialization,
intensive agriculture, and deforestation, the concentration of these GHGs has
risen to record levels in the last three million years. Hence, we need drastic
action now to combat climate change in the present and future.
3.13
Ozone Depletion
3.13.1
Ozone
Ozone with
chemical formula O3 is a colorless and active gas. It is the present
nearsurface of earth. It can cause rubber cracking, damage to the lungs, and
affects plant life also. However, in the stratosphere (15-30 km from earth’s
surface), ozone forms a protective covering and prevents the harmful
ultraviolet (UV)-B radiations from entering the earth’s atmosphere. The
thickness of the ozone layer is measured through Dobson’s Unit (DU).
3.13.2
Ozone Hole
Some
chemical reactions are causing rapid and severe destruction of ozone in the
southern polar region, and the main reactants are chlorine and bromine from the
past few decades. That depleted part of ozone is known as the ozone hole. In
1974, two scientists from the University of California had first detected the
threat to the ozone layer from CFCs.
3.13.3
Ozone-depleting Substance (ODS)
The
substances which release ozone on exposure to UV light in the stratosphere are
known as ODS. Chlorine-releasing ODS includes CFCs, HCFCs, methyl chloroform,
etc., whereas methyl bromide and halons release bromine. ODS is very stable and
cannot be easily dissolved by rain. These ODS substances are mainly used as
propellants, refrigerators, fire suppressors and foam insulators, etc.
Some
natural processes like volcanic eruptions also affect ozone concentration in
the stratosphere as they can release some aerosols, which increases chlorine’s
effectiveness in destroying ozone molecules.
3.13.4
Health Impacts of Ozone Depletion
The
depletion of ozone will increase the harmful UV-B radiations on earth, which
can cause skin cancer, immune deficiency disorders, and eye cataracts in
humans. It can alter plant growth and can affect the food chain and ecosystems.
3.13.5
Montreal Protocol
In 1987,
the Montreal Protocol was a landmark agreement signed by 197 countries to phase
out the ozone-depleting substances that is CFCs. After more than 30 years of
Montreal protocol, NASA scientists have found the recovery of ozone in the
Antarctic region for the first time.
A 20
percent decline is observed in the depletion of ozone since 2005. The UN has
projected that it would heal completely by the 2030s in the Northern
Hemisphere, by 2050s in Southern Hemisphere, and by 2060s in the Polar Regions.
3.14
Acid Rain
It is rain
with low pH due to contamination with acids like sulphuric acid (H2 SO4 ) and
nitric acid (HNO3 ). The major source of these acids is emissions of sulphur
and nitrous oxide from fossil fuels’ combustion, increasing their concentration
in the atmosphere. The vehicular exhaust also releases oxides of nitrogen into
the air. The pH of acid rain can range from 5.0 to 5.5 and sometimes 4 in
highly industrialized areas.
Deposition
of acid is classified into two categories: a) wet deposition like acid rain,
snow, and fog b) dry deposition like smoke, dust, and deposition as a particulate
matter.
The oxides
of nitrogen and sulphur can travel a long way through winds before coming in
contact with water vapours to form acid rain. Hence if sulphur and nitrogen
oxides are emitted fromurban industrial areas, the acid rain can fall in some
nearby rural areas.
3.14.1
Impacts
Acid rain
can decrease the pH of aquatic ecosystems. It causes foliar injury,
discoloration and reduces plant growth. It also reduces pollen germination and
fruit formation in plants. Vital nutrients in the soil get decreased due to
acid rain. Dry deposition can affect the heart and lungs in humans. Acid rain
also affects buildings and monuments by causing discoloration and marble
cracking.
3.14.2
Control of Acid Rain
Acid rain
can be controlled by minimum emissions of sulphur and nitrous oxides into the
atmosphere. The industries and factories should reduce their emissions, and
alternative fuels should be used in place of fossil fuels. Moreover, we can
minimize energy use by conserving it and using energy-efficient appliances,
vehicle maintenance, car-pooling, etc.
3.15
Biodiversity Loss
Biodiversity
is the variety of different species present on the earth. The species of plants
and animals are disappearing rapidly, mainly due to anthropogenic activities
like pollution, land use patterns, and climate change. This is known as
biodiversity loss. According to a UN (2019) report, one millionspecies out of
an estimated eight million are threatened with extinction.
Biodiversity
is very important for our planet. It has many values, such as:
·
It provides food, pharmaceuticals, and fuel
·
Forests act as carbon sinks and reduce global warming
·
Pollination occurs due to biodiversity
·
It helps in ecosystem regulation
·
Many optional values are provided due to the variety
of plants and animals
·
Our cultural and social values are also related to
biodiversity
Hence, we
need to protect our biodiversity as it has great importance. The reasons responsible
for biodiversity loss are:
·
Deforestation
·
Urbanization
·
Intensive agriculture
·
Hunting
·
Over-exploitation
·
Climate change
·
Pollution
·
Alien or invasive species
3.16
Electrical and Electronic Waste
Electrical
waste or E-waste includes discarded electronic appliances such as the keyboard,
monitors, motherboards, mobile phones, laptops, chargers, headphones,
televisions, and air conditioners, etc. According to a report of Global E-Waste
Monitor 2017, India generates around two million tonnes of E-waste per year,
and India’s ranking is at 5th among countries producing e-waste, after the US,
China, Japan, and Germany. As per the report of UN (2019), only 20% of global
e-waste is recycled. E-waste is composed of many kinds of materials, which are
briefly mentioned in table below.
|
Material |
Percentage in E-waste |
|
Iron and steel |
50% |
|
Non-ferrous metal |
13% |
|
Plastic |
21% |
|
Mercury, arsenic. Lead
etc. |
Traces |
In the recent past, the use of electrical and electronic
equipment (EEE) has grown. However, their life span is becoming shorter day by
day. The disposal of E-waste is a critical issue in the 21st century. Most of
the developing countries lack the infrastructure needed for proper disposal and
recycling of E-waste. Many disorders are linked with E-waste, such as cancer,
respiratory and neurological disorders, and congenital disabilities.
Moreover, a
well-established system is not available for collecting, separation, storage,
transportation, and disposal of e-waste. Also, E-waste has a complex nature and
hence is somewhat complicated in handling and disposal. In addition to this, no
effective enforcement of laws and regulations is implemented to E-waste
disposal and management.
3.17
Urban Sprawl
Urban sprawl
is referred to as another term for urbanization. It is defined as the migration
or movement of people from populated or crowded towns towards low-density areas
or rural lands. It results in the spreading of a town or city into more and
more suburbs over rural areas.
3.17.1
Characteristics of a Sprawl
There are some common characteristics for a sprawl,
mentioned below:
·
Availability of a large lot of land for single-family
dwellings
·
Large distances are created among dwellings, and they
depend on private automobiles for short trip distances also
·
Sprawls have dispersed development or leapfrog
development patterns, and people are located on lands adjacent to one another
·
Community distinctiveness declines in urban sprawl
·
People’s desire for more residential amenities leading
to urban sprawl
3.17.2
Impacts of an Urban Sprawl
·
It causes more energy use and pollution
·
Dispersion of communities to long distances
·
Destruction and fragmentation of wildlife habitats
·
Traffic congestion
3.18
Traffic Congestion
The traffic
congestion results from the increased number of traffic on roads and its
consequences are long travel times and higher emissions which affects air quality.
In other words, the higher number of cars, trucks, and buses on roads and a
greater number of pedestrians on sidewalks describes the scene of congestion.
Traffic
congestion can be of many types depending on the reason for congestion. These
are described below:
1. Environment: If the
weather is rainy or foggy, it results in halted traffic on roads. Sometimes
extreme snowstorms and other disasters can lead to prolong traffic on roads
2. Mechanical: If any
vehicle is slipped on-road or has any accident, it can cause traffic
congestion. Broken roads and unmaintained vehicles can also stop traffic in the
long run. Some mechanical fallings of the building or other accidents such as
landslides can cause traffic to stop. Sometimes the traffic control devices and
toll taxes also cause congestion of traffic.
3. Human
causes: A drowsy or drunken driver can be very dangerous not only
for the traffic but also for the lives of people. Sometimes an untrained driver
can lead to a traffic halt.
4. Infrastructure: Some
traffic problems are caused by inadequate infrastructure, which is although a
human-made cause. Some potholes cause slowdown of the traffic, and some
bottleneck roads also lead to traffic problems
The other
causes responsible for traffic congestion include increasing population and
urbanization. Due to this, people demand their personalized vehicles for
movements, and its outcomes are traffic congestion.
Some steps that can be taken to
control traffic congestion are:
·
Reforms in Urban planning and urban development
policies
·
Promotion of public transports
·
Intelligent transport systems such as Bus Rapid
Transit (BRT) System
3.19
Socio-economic Problems
The
socio-economic factors influence a person’s economic activities, such as
education, food, and employment. Socio-economic problems include lack of
education, scarcity of food, unemployment, cultural discrimination, corruption,
etc.
Lower
socio-economic status is associated with many health problems such as cancer,
arthritis, low birthweight, and hypertension. Moreover, it increases mortality
rates also, and more disparities are found in middle adulthood or the age of 45-65
years.
3.19.1
Components of Socio-economic Status
1. Education: The
earning potential of a person and his future opportunities are dependent
directly on his education status. It helps in getting good social behaviour,
better health, and good income also.
2. Income: A good
income helps make good health and nutrition, better lifestyle including
housing, schooling, and other recreational activities.
3. Occupation: It is
believed that an employed person would have better health than an unemployed
one as long-term unemployment increases job insecurity and anxiety.
3.19.2
Environmental Exposure and Socio-economic Status
People with
lower socio-economic status are more prone to work in a worse environment, like
more polluted and unhygienic conditions. People in the low poverty line have
their house locations in industrial areas, near highways, or toxic waste sites
because of cheaper land availability. They also experience more noise and
crowding. Higher noise levels sometimes increase hypertension in adults and
poor memory in children. Chronic stress due to overcrowded housing and long
working hours are also consequences of lower socioeconomic status.
3.20
Let Us Sum Up
This unit
has discussed major global environmental issues such as climate change, global
warming, ozone depletion, and regional and local issues like pollution, forest
degradation, and water scarcity. This knowledge helps us understand various
causes and impacts of different environmental problems and their solutions and
contribute to environmental conservation.
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