GLOBAL WARMING:

Causes, Impacts and Remedial Measures

Presented by

Dr. P. K. Patil

Head & Associate Professor, Geography,

JET‟s Zulal Bhilajirao Patil College, Dhule

Year Population (Crore)

1 AD 10

1600 AD 40

1750 AD 80

1950 AD 250

1987 AD 500

2015 AD 750

Population Growth

Interference of Man in the Environment

•Interference of man in the environment is increasing day by day.

•The changing relationships of man with the natural environment

from prehistoric to modern periods may be divided into four stages:

1) Period of hunting and food gathering•Hunting of animals was the first step of man in the exploitation of

natural resources.

•He learned to cook animal flesh before eating.

•The discovery of fire and invention of tools and weapons made the

man capable of exploiting natural resources from the forest.

•The first destruction of environment started with clearing or

burning of forests.

•However, due to mobile tendency of early man, there was least

interference with the environment in terms of its destruction.

2) Period of Animal Domestication and Pastoralism:

•With the march of time early man learned to domesticate animals

•Man used to burn forest to create home for the animals.

•Group or community life started. Their way of life was nomadic.

•During this period man could not change the natural

state of environment, because the population was

limited and changes were within limits of self regulatory

mechanism.

3) Period of Plant Domestication and Agriculture:

•Domestication of plants for food was a hallmark in the development of

human skill.

•It initiated primitive type of agriculture and settlements.

•The emergence of human civilization and farming practices changed

the existing friendly relationship between man and his environment.

•Continuous improvement in farming practices resulted into gradual

increase in human population and domestic animals.

More and more virgin forest lands were cleared in order to increase

the agricultural land.

•With the march of time man developed his own environment known as

„the cultural environment‟ by building houses, roads, railway routes,

bridges, etc.

Due to technological development the physical and

social man changed to economic man.

But no serious damage was done to the natural

environment and the nature was still supreme and master.

4) Period of Science, Technology and Industrialization:

•Due to science and technology development, the industrial

revolution started in late nineteenth century (since 1860).

In the modern period, man started reckless and rapid exploitation of

natural resources for industrial expansion and urban growth.

•To increase the area under agriculture as well as for other

commercial purposes, the forests and grasslands have been

destroyed on a large scale by man.

•Over utilization of resources and release of several

pollutants into the nature have created several

environmental problems such as ecological imbalance,

environmental pollution, depletion of ozone, and global

warming.

In the modern period the relationship between man and

environment has become hostile.

Environmental Problems

• Degradation of Resources

• Environmental Pollution – Air, Land, Water, Noise etc

• Ecological Imbalance

• Extinction of certain species of flora and fauna

• Ozone Depletion

• Global Warming and Climate Change

Anthropogenic Factors Responsible for Global Warming and

Other Environmental Problems

1. Ever Increasing Human Population

2. Urbanization

3. Agriculture

4. Overgrazing

5. Deforestation

6. Industries

7. Mining

8. Modernization

9. Transportation (Auto vehicles)

10.Power Generation

11.Wars

Global Warming Question?

“Global warming is referred to as the process of

increase in average temperature of the earth‟s

surface and atmosphere”.

It is one of the most serious global environmental

problems faced by the world community.

The average global air temperature near the

Earth's surface increased 0.74 ± 0.18 °C (1.33 ± 0.32

°F) during the last 100 years period.

An increase of one degree Celsius makes the Earth

warmer now than it has been for at least a thousand

years. Out of the 20 warmest years on record, 19

have occurred since 1980.

What is Global Warming?

Atmosphere: An envelop of air surrounding to the earth is

called atmosphere

Composition of Atmosphere

The atmosphere is composed of three elements, i.e.

gases, water vapour and dust particles.

1) Gases:About 99 percent of the volume of atmosphere is

occupied by different gases.Table: Principal Gases of Dry Air of Lower Atmosphere

Sr.

No.

Constituent Percent by

Volume

1

2

3

4

5

Nitrogen (N2)

Oxygen (O2)

Argon (Ar)

Carbon Dioxide (CO2)

Ne, He, CH4, Kr, H2, Xe, O3 etc.

78.08

20.95

0.93

0.03

0.01

Total 100.00

2) Water Vapour

•W.V. is highly variable constituent of atmosphere. It is added into the

atmosphere by evaporation process.

•The proportion of water vapour varies from 0.02 percent by volume in

dry climate to about 4 percent in the humid climate.

•The proportion of W.V. also decreases with altitude. It is almost absent

above 20 km.

•The water vapour plays an important role in environment.

•The heat is transferred from earth‟s surface to atmosphere through

water vapour and is also stored in it. This is called as latent heat.

•It is able to absorb heat and acts as an insulating blanket. Thus, it

prevents the rapid loss of heat from the earth.

•It absorbs not only the long wave radiation, but also a part of incoming

solar radiation.

3) Solid Particles (Particulates)

The lower atmosphere contains innumerable microscopic

solid particles, called as particulates. They are of two types:

i) Organic particles: Tiny seeds, pollen grains, bacteria, etc.

ii) Inorganic particles: Rock particles, salt, smoke etc.

•Particulates and gaseous molecules deflect some of the

incoming sunrays and thus, diffuse light in all directions.

•The sky appears blue due to selective scattering of S.R.

•The red colour at the time of sunrise and sunset as well as

the occurrence of twilight is due to scattering of solar

radiation by dust particles.

•The hygroscopic particulates are useful for the formation

of water drops, clouds and various forms of condensation

and precipitation.

Structure of Atmosphere

• On the basis of chemical composition and physical properties,

the atmosphere can be divided into different layers as:

A) Homosphere

• Chemical composition is highly uniform in terms of proportion of

gases.

• Extended from the earth surface to 80 km elevation.

• On the basis of temperature changes, it can be divided into three

layers:

i) Troposphere:

• The lowermost layer of the atmosphere.

• Average height - 12 km.

• Contains 75 percent of the gaseous mass of atmosphere and

most of the water vapour and particulates.

• Temperature decreases with increasing height at the rate of 6.40

C per km (Normal Lapse Rate).

• The weather phenomena like clouds, fog, frost, dew, rainfall,

snowfall, lightning etc. occur only in the troposphere.

ii) Stratosphere:

•Extended from tropopause to 50 km elevation.

•Divided into 2 sub layers i.e., Lower & Upper Stratosphere.

•Lower Stratosphere (up to 20 km elevation) is isothermal in nature.

•Upper Stratosphere (20 to 50 km elevation): Air temperature

increases gradually with increasing height.

•Temperature increases due to absorption of ultra violet radiation by

ozone.

•It contains much of the atmospheric ozone, and hence it is also

called as ozonosphere.

•The ozone absorbs much of the ultra violet rays coming from the

sun and thus, protects the earth surface from intensive heat.

iii) Mesosphere:•Extended from 50 to 80 km elevation.

•In this zone, temperature again decreases with increasing height.

•At the uppermost limit of mesosphere, the temperature is about

minus 80 degree C.

B) Heterosphere:

• Chemical composition of the atmosphere is not uniform.

•Extended from 80 km to 10,000 km elevation.

•It consist of four distinct layers of gases.

a) Nitrogen Layer: 80 to 200 km.

b) Oxygen Layer: 200 to 1100 km.

c) Helium Layer: 1100 km to 3500 km.

d) Hydrogen Layer: 3500 km to 10000 km.

•The heterosphere is also called as thermosphere, because in this

zone temperature continuously increases with increasing height.

•At the top of thermosphere (at 10,000 km elevation) the temperature

is about 5500 0 C.

•This layer is further divided into two sub layers i.e.

a) Ionosphere – 80 to 640 km

b) Exosphere. – above 640 km

Insolation (Incoming Solar Radiation)

•The Sun is the single major source of heat to the earth and its

atmosphere.

•The earth receives about 99.95 percent of the energy from the Sun and

only 0.05 percent of the energy from other sources.

•Solar energy plays an important role in controlling our weather and

climate.

•The sun is the gaseous mass. Chief components of the sun are

hydrogen (H2) and helium (He).

•In the interior parts of the sun, hydrogen is continuously converted into

helium by the process of nuclear fusion. In this process tremendous

heat is continuously generated.

•This heat is transported to the outer surface of the sun through the

process of convection and conduction.

•In the interior parts of the sun, temperature is about 5,00,000 0 C, while

at the surface of the sun, it is about 6,000 0 C.

•Due to continuous supply of heat, the surface of the sun

emits the energy to all directions in the form of

electromagnetic waves, called as electromagnetic radiation

or solar radiation.

•It travels at the speed of 2,96,000 km per second and

requires 8 minutes and 20 seconds to reach up to the earth.

•The amount of solar energy received by the earth and its

atmosphere is called as „Incoming Solar Radiation‟ or

„Insolation‟.

•Out of the total solar radiation, only two billionth part (1 /

2,000, 000, 000) reaches up to the earth.

•It is equivalent to 230 lakh million horse power. It is sufficient

to create all the atmospheric and biological processes.

• The Sun gives out energy in the form of electromagnetic waves that

varies in length.

• The straight distance between two successive crests OR trough is

called as wavelength ().

• It is expressed in the units of meter, cm, mm, micron (1 micron or

micrometer (µ) = 0.0001 cm) and angstrom (1 A 0 = 10-7 cm).

• The electromagnetic waves come in the form of electromagnetic

spectrum. It consists of gamma () rays ( = less than 0.03 A0 ), X

rays ( = 0.03 A0 to 100 A0 ), ultraviolet rays ( = 0.1 to 0.4 µ), visible

rays ( = 0.4 to 0.7 µ), infrared rays ( = 0.7 to 300 µ), microwaves ( =

0.03 cm to 100 cm) and radio waves ( = above 100 cm).

• In the electromagnetic spectrum, about 9 percent solar radiation is

in the form of ultraviolet rays, 41 percent in the form of visible rays

and 45 percent in the form of infrared rays. Thus, about 95 percent

energy is transmitted in the form of ultraviolet rays, visible rays and

infrared rays.

Heat Balance of the Earth & Atmosphere

Causes of Global Warming:

Main Causes

i) Emission of Greenhouse Gases

ii) Ozone Depletion

iii) Deforestation

Other human activities

burning of agricultural residues

burning of biomass for fuel needs

unhealthy maintenance of animals

industrial emission

Transportation, etc. also leading to global warming.

Greenhouse Effect

Source: Intergovernmental Panel on Climate Change

240 Watt per m3

343 Watt per m3

103 Watt per m3

Greenhouse Gases

• Carbon dioxide (CO2)

• Methane (CH4)

• Nitrous oxide (N2O)

• Hydrofluorocarbons (HFCs)

• Perfluorocarbons (PFCs)

• Sulphur hexafluoride (SF6)

Water vapour is also considered a greenhouse

gas.

Source: Kyoto Protocol- Annexure A

Natural

Manmade

Name of the

Gas

Prop. Before

Ind. Revolution

Proportion At

Present

Annual Growth

Rate

Carbon

dioxide

280 ppm 380 ppm 1.4 ppm

Methane 0.75 ppb 165 ppb 17 ppb

CFC 0 400 ppt 19 ppt

Nitrous

Oxide

280ppb 305 ppb 0.6 ppt

Proportion of Greenhouse Gases Before Industrial Revolution

and at Present Period

Rising levels of greenhouse gases

Source: Stern Review

Carbon Emission Data

0

1

2

3

4

5

6

World USA OECD Asia

Per Capita Carbon Emissions

DEPLITION OF OZONE

Where is the ozone layer?

• The ozone layer is a

protective layer of gas

molecules located

within the stratosphere.

• Ozone gas also exists

in the troposphere and

at ground level, but

most is located within

the stratospheric layer.

The Ozone Layer is in the Stratosphere

Why is it important to life on

Earth?• On a daily basis, the sun radiates its energy toward

Earth. One form of this energy is UltraViolet radiation, also known as UV rays.

• UV rays are relatively high energy waves that provide Earth with the warmth it needs to support life as we know it.

Source: NASA

•Ozone protects living

organisms by absorbing

harmful ultraviolet radiation

(UVB) from the sun.

• The ozone layer absorbs 97–

99% of the Sun's medium-

frequency ultraviolet light ,

which potentially damages

exposed life forms on Earth.

•The ozone layer is being

destroyed by CFCs and other

substances.

• Ozone depletion progressing

globally except in the tropical

zone.

The ozone layer

www.epcc.pref.osaka.jp/apec/ eng/earth/ozone_layer_depletion/susumu.html

Ultra-Violet Radiation

• UV rays penetrate

the Earth’s

atmosphere at 3

slightly different

wavelengths called

UV-A, UV-B, and

UV-C rays.

So, why is the ozone layer

important to life on Earth?

• The stratospheric ozone

layer completely stops

the penetration of UV-C

rays and eliminates

most of the UV-B rays.

• Therefore, the ozone

layer protects life on

Earth from the harmful

effects of solar radiation

on a daily basis.

Source: NASA

“Ozone-depleting substances" (ODS)

• Certain chemicals (such as chlorofluorocarbons, hydro-

chlorofluorocarbons and halons) are recognized as ozone-

depleting substances (ODS) because they breakdown in the

stratosphere and release chlorine or bromine, which destroy the

stratospheric ozone layer.

• Most ODS are also greenhouse gases.

• Ozone-depleting substances are generally used as refrigerants,

foam blowing agents, solvents, aerosol spray propellants, fire

extinguishing agents and chemical reactants etc.

Chlorofluorocarbons (CFC’s)

Advantages

• Nontoxic/Non-reactive

• Nonflammable

• Low Boiling Point

• Not Water Soluble

Uses

• Refrigerant gases

• Propellant for aerosol

cans

• Blowing agent to

make styrofoam

• Solvents

• CFCs

– What are CFCs? What are they used for?

– CFCs are chlorofluorocarbons; they are small molecules

that contain chlorine, fluorine and carbon atoms. Usually

there are only 1-2 carbon atoms.

– CFCs are sometimes called Freons (that was their trade

name for DuPont)

– CFCs are referred to by a number. The most common

CFCs are: CFC-11, CFC-12, CFC-113 (formulas on the

next page)

– HCFCs are CFCs that contain hydrogen. This makes them

more reactive to the OH radical, decreasing their

tropospheric lifetime. That means that, on a pound-per-

pound basis, HCFCs (“soft CFCs”) destroy less

stratospheric ozone than CFCs (“hard CFCs”) because a

smaller fraction of HCFCs “survive” to reach the

stratosphere

Methyl Chloride

Chloride

Hydro Chloride

Methyl Chloride

O3 O3

CF

C

CF

C

• Ozone is converted to oxygen

• leaving the chlorine atom free

• resulting in a reduced level of ozone

• in 1985 evidence of a large "ozone hole" was

discovered above the continent of Antarctica during

the springtime.

two molecules of ozone are replaced by

three of molecular oxygen, leaving the

chlorine free to repeat the process:

CL O3 CLO O2+ R +

ClO O Cl O2+ R +

The “Ozone Hole”• What is the “ozone hole?” When did it first appear? How does it

form?

The ozone hole is the region

over Antarctica with total

ozone 220 Dobson Units or

lower. (The avg total column

ozone in the atmosphere is

about 300 DU.)

Ozone hole in Sept 2005. Source: NASA

Deforestation

Greenhouse Gas (GHG): Carbon Dioxide, Methane

Global GHG Emissions: 20 percent

Deforestation and forest degradation are responsible for at least 20 percent of

greenhouse gas emissions. The damage is two-fold: the world's capacity to

absorb CO 2 is reduced, while large amounts of stored carbon and methane are

released into the atmosphere. (Photo: Reuters)

Other Causes of Global WarmingTransportation

Greenhouse Gas (GHG): Carbon Dioxide (Global GHG Emissions: 13 percent)

Between 600 and 700 million cars, trucks, and buses worldwide produce about

about 13 percent of global man-made greenhouse gas emissions, according to

the UN. Passenger cars produce about on average 125 grams of CO2 per

passenger-kilometer, only 5 grams less than airplanes but nearly three times as

much as trains. (Photo: Reuters)

Warming

Road Transport

Air Pollution caused by emissions from factories

Greenhouse Gas (GHG): Carbon Dioxide, Methane

Global GHG Emissions: 6.3 percent

An oil platform stands in the Norwegian sector of the North Sea.

Extracting and refining oil and natural gas requires huge amounts of

energy while it also releases climate-warming methane gas from

underground into the air. According to the World Resources Institute,

oil and natural gas production is responsible for 6.3 percent of man-

made greenhouse gas emissions. (Photo: Reuters)

Oil & Gas Production

Greenhouse Gas (GHG): Nitrous Oxide

Global GHG Emissions: 6 percent

Bags containing ammonium nitrate fertilizer are stored in a warehouse in

Sydney. Modern agriculture relies heavily on fertilizers and pesticides,

which are manufactured from crude oil and natural gas and which release

nitrous oxide into the air, contributing to global warming. Nitrous oxide is

300 times more potent than carbon dioxide as a warming agent. The

World Resources Institute estimates that farming is responsible for 6

percent of global man-made greenhouse gas emissions. (Photo: Reuters)

Fertilizers

Greenhouse Gas (GHG): Methane

Global GHG Emissions: 5.1 percent

A cow in Argentina has its methane emissions collected in a plastic tank.

Argentine scientists say cows could be generating thirty percent of Argentina‟s

greenhouse gas emissions. Almost half of all global methane emissions comes

from belching livestock, mainly cows but also pigs, goats and sheep. Methane is

twenty times more potent as a greenhouse gas than carbon dioxide. (Photo:

Reuters)

Livestock

Greenhouse Gas (GHG): Carbon Dioxide

Global GHG Emissions: 4 percent

A laborer walks over newly made pipes at a cement plant in Yingtan,

China. There is huge demand for cement tanks to a global construction

boom. Cement production is very energy intensive, requiring first the

quarrying of limestone and then processing of that limestone at very high

temperatures. The carbon dioxide emitted by cement factories around the

world accounts for nearly 4 per cent of global greenhouse gas emissions,

according to the World Resources Institute. (Photo: Reuters)

Cement Production

Greenhouse Gas (GHG): Carbon Dioxide, Water Vapor, Nitrous Oxide,

Aerosols

Global GHG Emissions: 3.5 percent

A jet airliner leaves condensation trails. The trails are formed by soot and

water vapor from the plane‟s engines. The Intergovernmental Panel on

Climate Change (IPCC) estimates that aircraft emissions of water vapor,

nitrous oxides, aerosols and CO2 could be 2 to 4 times stronger than

emissions of CO2 alone. Aviation is responsible for 3.5 percent of man-

made global warming, says the IPCC, and it is the fastest growing source

of greenhouse gases. (Photo: Reuters)

Aviation

Most Global Warming Is Going Into

The Oceans

CLIMATE CHANGE

• Changes are natural property of the Earth System.

• But changes in last 150 years can not be compared with

any previous change

• We are in new geological era.

• At present we are in interglacial period.

• Industrial Revolution Started in 1860

• In the modern period climate has changed frequently.

Rise in sea level:

Sea levels have risen by 10 - 25 cm.

Due to global warming the permanent ice covers of the

Arctic and Antarctic regions are melting and would cause

flooding of rivers which meet to oceans. It resulted into rise

in sea level at considerable extent. It is also estimated that

the sea level will be increased by 1.5 to 5 meter at the end

of 21st century. Consequently, coastal areas will be flooded

and settlements will be submerged and agricultural fields

may be destroyed.

Change in rainfall patterns:

Rainfall patterns are changing around the world.

Research shows the global water cycle is intensifying with

a warming climate, which means wet areas are likely to get

wetter and dry regions are likely to be drier in response to

climate change.

Increase in extreme weather events:

Extreme weather events include heat waves, bushfires,

tropical cyclones, cold snaps, extreme rainfall and

droughts. There is increasing evidence that the frequency

and intensity of many extreme weather events are

changing.

Adverse effects of on human health:

Warmer temperatures could increase the concentrations of

unhealthy air and water pollutants. Changes in temperature,

precipitation patterns, and extreme events could enhance

the spread of some diseases.

Due to increase in temperature, few tropical and subtropical

diseases such as malaria, cholera, plague, dengue, fever,

yellow fever etc. will be gradually spread towards polar

areas.

Effects on livestock and other animals:

Climate change may increase the prevalence of parasites and

diseases that affect livestock. The earlier onset of spring and

warmer winters could allow some parasites and pathogens to

survive more easily. In areas with increased rainfall,

moisture-reliant pathogens could thrive.

Due to warming of sea water there will be decrease in

zooplanktons which are the main sources of penguin feeding.

It would cause their deaths from starvation.

Adverse effects on ecosystems:

Due to global warming and climate change, natural

ecosystems will be disrupted.

Adverse impact on agricultural Production:

Due to global warming, the agricultural production will be

decreased and human population will be displaced.

Observed changes

•Since the mid-1800s, the average global temperature increased by

about 0.74 degrees C, impacting the entire world. For example, during

the 20th century

• global mean sea level rose by 10 to 20 cm,

• the overall volume of glaciers in Switzerland decreased by 2/3

• Arctic ice thickness in late summer and early autumn decreased by

about 40%, and

• Mount Kenya lost 92% of its ice mass while Mount Kilimanjaro lost

82%.

Other significant observed changes include:

• a 40-60% decrease in total available water in the large catchment

basins of Niger, Lake Chad and Senegal,

• the retreat of 70% of sandy shorelines, and

• a northward movement of some 100 km of Alaska‟s boreal forest

for every 1 degree C rise in temperature.

What changes might we expect in the future?•Computer models predict an average global temperature increase of 1.4 to

5.8 degrees C by the year 2100. Predicted impacts associated with such a

temperature increase include:

• a further rise in global mean sea level of 9 to 88 cm,

• more precipitation in temperate regions and Southeast Asia, associated with

a higher probability of floods,

• less precipitation in Central Asia, the Mediterranean region, Africa, parts of

Australia and New Zealand, associated with a greater probability of droughts,

• more frequent and powerful extreme climatic events, such as heat waves,

storms, and hurricanes,

• an expanded range of some dangerous “vector-borne diseases”, such as

malaria, and

• further warming of the Arctic and Antarctic, leading to more sea-ice

disappearance.

Why act now?

Climate change is already a reality. Even if all anthropogenic emissions were

to stop now, changes would continue into the future. We must, therefore,

increase climate change mitigation and adaptation efforts.

The Arctic has been heating up, and studies show that

is happening at two to three times the global average.

This rising temperature in the Arctic has served to

reduce the region‟s floating ice layer by more than 20%.

And as you would expect, when the reflective ice and

snow layer is stripped away, it leaves a dark blue sea.

Mount Kilimanjaro

(Tanzania_Africa) is

estimated to have lost 82% of

its ice mass during the

20th century.

Top picture February 17,1993;

Bottom picture February 21,

2000.

Iceberg detail in and around Crystal Sound near the Antarctic Circle on the

Antarctic Peninsula during the summer months More icebergs are being

created as global warming is causing the breakup ice Sheets

Remedial Measures to Prevent Global WarmingControl the exponential growth of population.

Adopt sustainable development policy.

Reduce and eliminate greenhouse gases emission.

Rational use of natural resources

Avoid over utilization of natural resources.

Adopt conservation policy in each field.

Reduce the production and consumption of CFC‟s to save the ozone

layer.

Development of non-conventional & pollution free energy resources.

Bio-fuels (ex.ethanol) should be used for automobiles.

Better management of transportation system.

Use of bicycles should be increased.

As forests are great natural sink of carbon dioxide, large scale

afforestation and reforestation should be taken up . (Plantation).

Sustainable farming and agro-forestry should be practiced.

Hands Surrounding to Earth

THANK YOU