ENVIRONMENT &
ECOLOGY (UNIT 4)
As per Latest AKTU Syllabus
GLOBAL WARMING
▪ Global warming refers to the long-term increase in Earth’s average surface temperature due to
human activities, particularly the emission of greenhouse gases from burning fossil fuels,
deforestation, and various industrial processes.
▪ This phenomenon is primarily driven by the enhanced greenhouse effect, where gases like carbon
dioxide (CO2), methane (CH4), nitrous oxide (N2O), and water vapor trap heat in the Earth’s
atmosphere, preventing it from escaping into space.
▪ Since the late 19th century, the global average temperature has risen by approximately 1.1°C.
▪ This warming trend has accelerated over the past century, largely due to the increased burning of
fossil fuels such as coal, oil, and natural gas.
▪ These activities release significant amounts of CO2 and other greenhouse gases, which accumulate
in the atmosphere and enhance the natural greenhouse effect.
▪ Causes of Global Warming
1. Greenhouse Gases: The primary cause of
global warming is the increase in greenhouse
gases like carbon dioxide (CO2), methane
(CH4), and nitrous oxide (N2O). These gases
trap heat in the atmosphere, creating a
“greenhouse effect” that leads to warming.
2. Fossil Fuels: Burning fossil fuels such as coal,
oil, and natural gas for energy and
transportation releases significant amounts
of CO2.
3. Deforestation: Trees absorb CO2, and cutting
them down reduces the planet’s capacity to
absorb this gas, increasing its concentration
in the atmosphere.
4. Industrial Processes: Certain industrial
activities release greenhouse gases and other
pollutants that contribute to global warming.
Effects of Global Warming
1.Rising Temperatures: The global average temperature has increased by about 1.1°C since the late 19th century. This rise in
temperature affects weather patterns, leading to more frequent and severe heatwaves.
2. Melting Ice Caps and Glaciers: Higher temperatures cause polar ice caps and glaciers to melt, contributing to rising sea
levels.
3. Sea Level Rise: Melting ice and the thermal expansion of seawater as it warms lead to rising sea levels, which can cause
coastal flooding and erosion.
3. Extreme Weather Events: Global warming is linked to an increase in the frequency and intensity of extreme weather
events such as hurricanes, droughts, and heavy rainfall.
4. Impact on Ecosystems: Changes in temperature and precipitation patterns affect ecosystems and biodiversity. Some
species may struggle to survive, while others may thrive, leading to shifts in ecosystems.
5. Human Health: Increased temperatures can lead to heat-related illnesses and deaths. Changes in climate can also affect
the spread of diseases and impact food and water supplies.
Solutions to Global Warming
1.Reducing Emissions: Cutting down on the emission of greenhouse gases is crucial. This can be achieved by
transitioning to renewable energy sources like solar, wind, and hydroelectric power.
2.Energy Efficiency: Improving energy efficiency in homes, buildings, and transportation can reduce the amount of
energy needed and, consequently, the emissions produced.
3.Reforestation and Afforestation: Planting trees and restoring forests can help absorb CO2 from the atmosphere.
4.Sustainable Practices: Adopting sustainable agricultural and industrial practices can reduce emissions and
environmental impact.
5.International Agreements: Global cooperation through agreements like the Paris Agreement aims to limit global
warming to well below 2°C above pre-industrial levels.
Global warming is a critical issue that requires immediate and sustained action. By understanding its causes, effects, and
potential solutions, we can work towards mitigating its impact and ensuring a sustainable future for the planet.
GREENHOUSE EFFECT
▪ The greenhouse effect is a natural process that warms the Earth’s surface. When the Sun’s energy
reaches the Earth, some of it is reflected back to space and the rest is absorbed, warming the
planet. The Earth then emits heat in the form of infrared radiation. Greenhouse gases in the
atmosphere, such as carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O), and water vapor,
trap some of this heat, preventing it from escaping back into space. This trapped heat helps to
maintain the Earth’s temperature at a level suitable for life.
▪ How the Greenhouse Effect Works
1. Solar Radiation: The Sun emits energy that travels through space and reaches the Earth. This energy
includes visible light, ultraviolet light, and infrared radiation.
2. Absorption and Reflection: About 30% of the incoming solar radiation is reflected back into space
by clouds, atmospheric particles, and bright ground surfaces like ice and snow. The remaining 70% is
absorbed by the Earth’s surface, warming it.
3. Infrared Radiation: The warmed Earth emits energy in the form of infrared radiation. This radiation
travels back towards space.
4. Trapping Heat: Greenhouse gases in the atmosphere absorb and re-emit infrared radiation. This
process traps heat in the atmosphere, warming the Earth.
Importance of the Greenhouse Effect
The greenhouse effect is essential for life on Earth. Without it, the planet’s average temperature would be
about -18°C (0°F), making it too cold for most forms of life. The natural greenhouse effect keeps the Earth’s
average temperature at a comfortable 15°C (59°F).
Human Impact on the Greenhouse Effect
Human activities, particularly since the Industrial Revolution, have significantly increased the
concentration of greenhouse gases in the atmosphere. This enhancement of the greenhouse effect is the
primary driver of recent global warming. Key human activities contributing to this increase include:
1.Burning Fossil Fuels: The combustion of coal, oil, and natural gas for energy and transportation releases
large amounts of CO2 and other greenhouse gases.
2.Deforestation: Cutting down trees reduces the Earth’s capacity to absorb CO2, increasing its
concentration in the atmosphere.
3.Agriculture: Agricultural practices, including livestock farming, release methane and nitrous oxide.
4.Industrial Processes: Certain industrial activities release greenhouse gases and other pollutants.
Consequences of an Enhanced Greenhouse Effect
1.Global Warming: The increase in greenhouse gases leads to a rise in Earth’s average temperature, known as global
warming.
2.Climate Change: Global warming contributes to broader changes in climate patterns, including more frequent and
severe weather events such as hurricanes, droughts, and heavy rainfall.
3.Melting Ice Caps and Glaciers: Higher temperatures cause polar ice caps and glaciers to melt, contributing to sea level
rise.
4.Rising Sea Levels: Melting ice and the thermal expansion of seawater as it warms lead to rising sea levels, which can
cause coastal flooding and erosion.
5.Impact on Ecosystems: Changes in temperature and precipitation patterns affect ecosystems and biodiversity. Some
species may struggle to survive, while others may thrive, leading to shifts in ecosystems.
6.Human Health: Increased temperatures can lead to heat-related illnesses and deaths. Changes in climate can also
affect the spread of diseases and impact food and water supplies.
Mitigating the Enhanced Greenhouse Effect
1.Reducing Emissions: Cutting down on the emission of greenhouse gases is crucial. This can be achieved by
transitioning to renewable energy sources like solar, wind, and hydroelectric power.
2.Energy Efficiency: Improving energy efficiency in homes, buildings, and transportation can reduce the amount of
energy needed and, consequently, the emissions produced.
3.Reforestation and Afforestation: Planting trees and restoring forests can help absorb CO2 from the atmosphere.
4.Sustainable Practices: Adopting sustainable agricultural and industrial practices can reduce emissions and
environmental impact.
5.International Agreements: Global cooperation through agreements like the Paris Agreement aims to limit global
warming to well below 2°C above pre-industrial levels.
The greenhouse effect is a natural and essential process that warms the Earth. However, human activities have
enhanced this effect, leading to global warming and climate change. Understanding the greenhouse effect and its
impacts is crucial for developing strategies to mitigate climate change and protect the planet for future generations.
CLIMATE CHANGE
“Climate change” means a change of climate which is attributed directly or indirectly to human activity
that alters the composition of the global atmosphere and which is in addition to natural climate
variability observed over comparable time periods. However, when today people talk about ‘climate
change’, they mean the changes in climate over the last 100 years which is caused predominantly by
human activity.
The phrase ‘climate change’ represents a change in the long-term weather patterns. Climate change is
not a change of weather in a particular day; it is the cumulative change of long term weather pattern i.e.
changes in climate.
For example, it’s possible that a winter day in Jammu, could be sunny and mild, but the average
weather, the climate, tells us that Jammu’s winters will mainly be cold and include snow and rain. The
change in the pattern of Jammu’s winters from the normal winter pattern represents an epitome of
climate change. Climate change is the measurable effects of the continual warming trend.
Climate change is usually measured in major shifts in temperature, rainfall, snow, and wind patterns
lasting decades or more. Humans are creating climate change by burning large amounts of fossil fuels
(coal, oil, natural gas), deforestation (when forests are cut down or burned, they can no longer store
carbon, and the carbon is released to the atmosphere).
POPULATION GROWTH
A group of individuals of the same species living in the same area is called a population.
The measurement of the size of a population change over time is called the population growth rate,
and it depends upon the population size, birth rate, and death rate.
As long as there are enough resources available, there will be an increase in the number of
individuals in a population over time, or a positive growth rate.
However, most populations cannot continue to grow forever because they will eventually run out of
water, food, sunlight, space, or other resources.
As these resources begin to run out, the population growth will start to slow down. When the growth
rate of a population decreases as the number of individuals increases, this is called logistic
population growth.
If we look at a graph of a
population undergoing logistic
population growth, it will have
a characteristic S-shaped
curve.
The population grows in size
slowly when there are only a
few individuals. Then the
population grows faster when
there are more individuals.
Finally, having lots of
individuals in the population
causes growth to slow because
resources are limited.
In logistic growth, a population
will continue to grow until it
reaches carrying capacity,
which is the maximum number
of individuals the environment
can support.
Population Growth Rate
The population growth rate is a measure of how quickly the number of individuals in a population increases over a
specific period, typically expressed as a percentage of the initial population. This rate can be positive, indicating a
population increase, or negative, indicating a population decrease.
Automobile Pollution: Environmental Impacts of Transportation
While transportation activities enhance mobility for passengers and freight, they also contribute significantly to
environmental degradation. The transportation sector is a major source of various pollutants, leading to multiple
environmental impacts. These impacts include:
1.Climate Change: The transport industry emits millions of tons of gases annually, including lead (Pb), carbon monoxide
(CO), carbon dioxide (CO₂; not a pollutant), methane (CH₄), nitrogen oxides (NOₓ), nitrous oxide (N₂O),
chlorofluorocarbons (CFCs), perfluorocarbons (PFCs), sulfur hexafluoride (SF₆), benzene, volatile organic compounds
(BTX), heavy metals (zinc, chrome, copper, cadmium), and particulate matter (ash, dust).
2. Air Quality: Emissions from vehicles, marine engines, locomotives, and aircraft release gases and particulate matter
that degrade air quality, posing health risks such as cancer, cardiovascular, respiratory, and neurological diseases.
3. Noise Pollution: Irregular and chaotic sounds from transportation sources can be harmful to hearing and overall well-
being. Prolonged exposure to noise levels above 75dB can severely impact hearing and physical and psychological health.
4. Water Quality: Transportation activities can contaminate water bodies through the release of fuel, chemicals, and
hazardous particulates from vehicles and terminal operations, affecting rivers, lakes, wetlands, and oceans.
5. Soil Quality: Transportation impacts soil through erosion and contamination. The use of heavy metals and chemicals
can degrade soil quality, affecting agriculture and ecosystems.
6. Biodiversity Loss: Infrastructure like roads and railways can fragment habitats, creating barriers for wildlife and leading
to biodiversity loss and ecosystem disruption.
7. Energy Consumption: The transportation sector is a major consumer of fossil fuels, contributing to the depletion of
natural resources and increasing greenhouse gas emissions.
8. Urban Sprawl: The expansion of transportation networks often leads to urban sprawl, increasing land consumption
and reducing green spaces, which can harm natural habitats and elevate pollution levels in cities.
9. Waste Generation: The production, maintenance, and disposal of vehicles generate significant waste, including
hazardous materials, which can contaminate soil and water if not properly managed.
Paddy Straw Burning: Definition and Overview
Definition: Paddy straw burning refers to the practice of setting fire to the leftover stalks and straw of paddy (rice)
plants after the grains have been harvested. This method is commonly used by farmers to quickly clear their fields
for the next planting season.
Causes:
1.Short Time Frame: Farmers have a limited window between the harvesting of paddy and the sowing of the next
crop, usually wheat. This short period compels them to quickly clear the fields by burning the straw.
2.Economic Constraints: The cost of alternative methods for managing paddy straw, such as using machinery or
converting it into biofuel, can be prohibitive for many farmers.
3.Lack of Awareness: Many farmers are not fully aware of the environmental and health impacts of straw burning
or the benefits of alternative practices.
4.Labor Shortage: There is often a scarcity of labor available for manual removal of straw, making burning a more
convenient option.
Impacts:
1.Air Pollution: Burning paddy straw releases significant amounts of pollutants, including particulate matter (PM),
carbon monoxide (CO), carbon dioxide (CO₂), nitrogen oxides (NOₓ), and sulfur dioxide (SO₂). For instance, burning
one ton of paddy straw can release 3 kg of particulate matter, 60 kg of CO, 1,460 kg of CO₂, 199 kg of ash, and 2 kg
of SO₂.
2.Health Hazards: The pollutants released can cause severe health issues, including respiratory problems,
cardiovascular diseases, and cancer. Vulnerable groups such as children, the elderly, and pregnant women are
particularly at risk.
3.Soil Degradation: Burning straw can lead to the loss of essential nutrients in the soil, such as nitrogen,
phosphorus, and potassium. It also reduces soil organic carbon, affecting soil fertility and structure.
4.Climate Change: The release of greenhouse gases (GHGs) like CO₂ and methane (CH₄) from straw burning
contributes to global warming and climate change.
5.Water Quality: The ash and residues from burning can contaminate water bodies, affecting aquatic life and water
quality.
Mitigation Measures:
1.Alternative Uses: Paddy straw can be used for producing bioenergy, compost, and as animal fodder.
2.Technological Solutions: Machines like the Happy Seeder can sow seeds without removing the straw, reducing the
need for burning.
3.Government Policies: Implementing stricter regulations and providing incentives for farmers to adopt sustainable
practices can help reduce straw burning.
4.Awareness Campaigns: Educating farmers about the adverse effects of straw burning and the benefits of
alternative methods can encourage more sustainable practices.
