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2010

Independent University

Bangladesh

Global Warming andClimate Change

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Introduction to Environmental Science (ENV. 101)

PREPARED BY:

Atiqur Rahman 0930173

Gazi Zonayet Hossain 0930120

Kazi Mustafizur Rahman 0930161

Purna Saha 1020689

SUBMITTED TO:

Dr. Shahana Afrose Chowdhury

Assistant professor, SESM.

Date of Submission: 12th April 2010.

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Table Of Content Page

1.1 What is global warming? IV

1.2 What is green house effect? IV

1.3 The green house gases V

1.4 What is the impact of global warming on environment? VI

1.5 What causes global warming? VII

2.1 What is climate? X

2.2 Global warming and climate change? XI

3.1 Threat to Bangladesh. XVII

4.1 Lets save the world. XXI

5.0 References and Division of Work. XXII

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1.1 What is global warming?

Global warming is simply when the earth heats up (the temperature rises). It happens when

greenhouse gases (carbon dioxide, water vapor, nitrous oxide, and methane) trap heat and light

from the sun in the earths atmosphere, which increases the atmospheric temperature. The earths

mean temperature has risen by about 0.6 degrees Celsius in the 20th century. Investigations and

other research predict that the world temperature would increase by 3 to 5 degrees Celsius by the

year 2100. The main reason behind this rapid change in global temperatures is due to human

activities which have led to an enormous emission of carbon dioxide and other harmful green

house gases. There are also some natural causes but almost 100% of the observed temperature

increase has been due to the overwhelming concentrations of the green house gases in the

atmosphere.

1.2 What is green house effect?

The greenhouse effect is caused by an atmosphere containing gases that absorb and emit infraredradiation. Greenhouse gases trap heat within the surface-troposphere system, causing heating at

the surface of the planet or moon. This mechanism is fundamentally different from that of an

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actual greenhouse, which works by isolating warm air inside the structure so that heat is not lost

by convection. The greenhouse effect was discovered by Joseph Fourier in 1824, first reliably

experimented on by John Tyndall in 1858, and first reported quantitatively by Svante Arrheniusin 1896. The black body temperature of the Earth is 5.5 C. Since the Earth's surface reflects

about 28% of incoming sunlight, in the absence of the greenhouse effect the planet's mean

temperature would be far lower - about -18 or -19 C instead of the much higher current meantemperature, about 14 C.

Global warming, a recent warming of the Earth's surface and lower atmosphere, is believed to be

the result of an "enhanced greenhouse effect" mostly due to human-produced increases in

atmospheric gases. This human induced part is referred to as anthropogenic global warming

(AGW).

1.3 The green house gases

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The contribution to the greenhouse effect by a gas is affected by both the characteristics of the

gas and its abundance. The gases mentioned below are simply the major gases that influence

green house effect and thermal radiation and each gas can be classified in a broader sense. For

example the chlorofluorocarbons which include carbon, chlorine, and fluorine, produced as a

volatile derivative of methane and ethane. A common subclass is the

hydrochlorofluorocarbons (HCFCs), which contain hydrogen, as well.

water vapor

carbon dioxide

methane

nitrous oxide

sulfur oxides

chlorofluorocarbon

1.4 What is the impact of global warming on environment?

Global warming is affecting many parts of the world. Global warming makes the sea level to

rise and the consequence is many low lands under water. This is a big problem for many of the

living organisms on those lands. The water covers the plants and causes some of them to die.

When they die, the animals lose a source of food, along with their habitat. Although animals

have a better ability to adapt to what happens than plants do, they may die also. When the plantsand animals die, people lose two sources of food, plant food and animal food. They may also

lose their homes. As a result, they would also have to leave the area or die. This would be called

a break in the food chain, or a chain reaction, one thing happening that leads to another and so

on.

The oceans are affected by global warming in other ways, as well. Many things that are

happening to the ocean are linked to global warming. One thing that is happening is warm

water, caused from global warming, is harming and killing algae in the ocean.

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Fig: Rise in sea level through the last century

Algae are a producer that you can see floating on the top of the water. (A producer is something

that makes food for other animals through photosynthesis, like grass.) These floating green algae

are food to many consumers in the ocean. (A consumer is something that eats the producers.)

One kind of a consumer is small fish. There are many others like crabs, some whales, and many

other animals. Fewer algae are a problem because there is less food for us and many animals in

the sea.

Global warming is also destroying many huge forests. The pollution that causes global warming

is linked to acid rain. Acid rain gradually destroys almost everything it touches. Global

warming is also causing many more fires that wipe out whole forests. This happens because

global warming can make the earth very hot. In forests, some plants and trees leaves can be so

dry that they catch on fire. Moreover due to this acid rain the land is becoming barren and as a

result degradation is very prone to take place.

1.5 What causes global warming?

Many things cause global warming. One thing that causes global warming is electrical pollution.

Electricity causes pollution in many ways, some worse than others. In most cases, fossil fuels

are burnt to create electricity. Fossil fuels are made of dead plants and animals. Some examples

of fossil fuels are oil and petroleum. Many pollutants (chemicals that pollute the air, water, and

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land) are sent into the air when fossil fuels are burned. Some of these chemicals are called

greenhouse gasses such as carbon dioxide, sulfur dioxide, etc.

We use these sources of energy much more than the sources that give off less pollution.

Petroleum, one of the sources of energy, is used a lot. It is used for transportation, making

electricity, and making many other things. Some other examples are using electrical appliances

such as televisions, refrigerators, air conditioners and other purposeful and recreational

instruments.

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When you do these things, you are causing more greenhouse gasses to be sent into the air.

If you think of how many times a

day you switch on your air conditioners, its a lot. You even have to add in how many other

people do these things! That turns out to be a lot of pollutants going into the air a day because of

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people like us using electricity. The least amount of electricity you use, the better you take care

of the environment.

When we throw our garbage away, the garbage goes to landfills. Landfills

are those big hills that you go by on an expressway that stink. They are full

of garbage. The garbage is then sometimes burned. This sends an enormous

amount of greenhouse gasses into the air and makes global warming worse.

Another thing that makes global warming worse is when people cut down

trees. Trees and other plants collect carbon dioxide (CO2), which is a greenhouse gas. Carbon

dioxide is the air that our body lets out when we breathe. With fewer trees, it is harder for people

to breathe because there is more CO2 in the air, and we dont breathe CO2, we breathe oxygen.

Plants collect the CO2 that we breathe out, and they give back oxygen that we breathe in. With

fewer trees and other plants, such as algae, there is less air for us, and more greenhouse gases are

sent into the air. This means that it is very important to protect our trees to stop the greenhouseeffect, and also so we can breathe and live. This gas, CO2, collects light and heat (radiant

energy), produced by the sun, and this makes the earth warmer. During the last century this

global warming had an adverse effect on the earths climate. This rapid climatic change is

affecting all the living organisms and nature in a very unusual way and heading the earth towards

a disrupted living place.

2.1 What is climate?

Climate is the condition of the atmosphere at a particular location over a long period of time,

generally 30 years. Climate is the sum of atmospheric elements and their variations: solar

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radiation, temperature, humidity, clouds and precipitation, atmospheric pressure, and wind. To

the nonspecialist, climate means expected or habitual weather at a particular place and time of

year.

The climate of a location is affected by its latitude, terrain, altitude, ice or snow cover, as well as

nearby water bodies and their currents. Climates can be classified according to the average andtypical ranges of different variables, most commonly temperature and precipitation. Climate is

commonly defined as the weather averaged but the difference between climate and weather is

usefully summarized by the popular phrase "Climate is what you expect, weather is what youget." Climate has been classified by scientists from the ancient times in different ways according

to locations, area, icecaps, forest, fountains and other meteorological factors.

2.2 Global warming and climate change?

Global warming has been a big issue over the last decade and lots of world conferences have

been held and affected nations have raised their voice against this. Though many controversies

exist, let us explore the facts and scientific discoveries, how global warming has influenced

climate change and why the world nations are now so concerned about this change.The biggest climatic change our earth is having is the melting down of snow glaciers and ice

caps due to increase in global temperature. As a result many low land areas would be submerged

by water leaving many people homeless and other plant and animal species towards extinction.

Degradation of rainforests would emerge due to the change in precipitation rate and invasivespecies are manifesting majority of which are threat to the existing species.

Temperature increase is also changing the wind pressure in different zones which are affecting

the irrigation and blooming season. As a result early or delayed yield leads to an unsecured food

supply for the world.

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There are many plant and animal species which would move towards extinction if the trend

continues such as polar bear, penguin etc. They would be homeless and human race would be

deprived of the benefits they could have extracted from them.

Fig. I: A comparison of the snow glaciers in Canada from 1917 to 2005

These changes are all due to manmade activities and this disruption could have a disastrous

effect on the food chain and human existence on this earth in the next 100 years.

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Fig. II: Changes of Mount Hood Oregon from 1984 to 2002

There are also some natural reasons apart from all human activities behind the change of the

climate as mentioned below but global warming is also influencing these factors to occur

rapidly and making the earth inhospitable.

Variations in the Earth's orbital characteristics.

Atmospheric carbon dioxide variations.

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Volcanic eruptions

Variations in solar output.

Variations in the earths orbital characteristics.

Ignoring all the theories on the climate change due to the earths orbital characteristics letsexplore how green house effect or in the sense global warming affecting the orbital

characteristics. Solar radiation is related to the change of orbital position of the earth over time.

When green house effect is getting serious, it means that the solar radiation on the earth surfaceis also varying rapidly and as a result it has an impact on the plates above the earths core leading

to earth quakes and other natural disasters.

Atmospheric carbon dioxide variations.

Over the years it has been observed that there is a connection between the concentration of

carbon dioxide and the global temperature. It is one of the more important gases responsible for

the greenhouse effect. Certain atmospheric gases like carbon dioxide, water vapor, and methane

gas can alter the energy balance of the earth by absorbing the long wave radiation emitted from

the earths surface thus building up the warm temperature. The net result of this process and the

re-emission of long wave back to the Earth's surface increases the quantity of heat energy in the

Earth's climatic system. Without the greenhouse effect, the average global temperature of the

Earth would be a cold -18 Celsius rather than the present 15 Celsius.

Over the past three centuries carbon dioxide emission has increased immensely due to human

activities such as the burning of fossil fuels, deforestation, and overpopulation and so on. This

change in the atmospheric carbon dioxide concentration is another major cause of climate

change. The carbon dioxide concentration in the atmosphere over the past years is shown below.

Moreover ocean acidification has also increased since carbon dioxide disolves in water making the sea

environment hostile and inhosptable for the ocean species.

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Fig-III: Carbon dioxide concentration.

Volcanic eruptions.

Volcanic eruption is another major cause of climate change and the emission of sulphur dioxide

into the atmosphere results in a short term cooling of the globes temperature. This is the only

coolant effect on the earths climate. At first it was thought that the dust emitted into the

atmosphere from large volcanic eruptions was responsible for the cooling by partially blocking

the transmission ofsolar radiation to the Earth's surface. However, measurements indicate that

most of the dust thrown in the atmosphere returned to the Earth's surface within six months.

Recent stratospheric data suggests that large explosive volcanic eruptions also eject large

quantities ofsulfur dioxide gas which remains in the atmosphere for as long as three years.Atmospheric chemists have determined that the ejected sulfur dioxide gas reacts with water

vapor commonly found in the stratosphere to form a dense optically bright haze layer that

reduces the atmospheric transmission of some of the Sun's incoming radiation.

http://www.physicalgeography.net/physgeoglos/s.html#solar_radiationhttp://www.physicalgeography.net/physgeoglos/s.html#stratopherehttp://www.physicalgeography.net/physgeoglos/s.html#sulfur_dioxidehttp://www.physicalgeography.net/physgeoglos/s.html#solar_radiationhttp://www.physicalgeography.net/physgeoglos/s.html#stratopherehttp://www.physicalgeography.net/physgeoglos/s.html#sulfur_dioxide

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Fig-IV: Ash column generated by the eruption of Mount Pinatubo on June 12, 1991.

The strongest eruption of Mount Pinatubo occurred three days later on June 15, 1991.

(Source: US Geological Survey).

Variations in the solar output.

Many scientists thought that suns radiation varied only by a fraction of a percent over many

years and it has no such impact over the earths climate. But recently the satellite

measurements and showed a different picture. Measurements made during the early 1980sshowed a decrease of 0.1 percent in the total amount of solar energy reaching the Earth over

just an 18 month time period. If this trend were to extend over several decades, it could

influence global climate. Numerical climatic models predict that a change in solar output ofonly 1 percent per century would alter the Earth's average temperature by between 0.5 to 1.0

Celsius. The only unlimited source of energy for the earth is sun and any changes in its

output will result in changes in the reception of insolation and the generation of heat energy

which drives the climate system. Greenhouse gases has a great impact on this variation sincewater vapor, smoke and particulate matters reacts to create smog, which prevents the flow of

sunlight on to the earth surface. This means lesser sunlight, lesser activity of the plants, lesser

absorption of carbon dioxide gas and lesser oxygen for us.

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3.1 Threat to Bangladesh.

Bangladesh is most vulnerable to several natural disasters and every year natural calamities upsetpeople's lives in some parts of the country. The tropical location and geographical setting of

Bangladesh makes the country vulnerable to natural disasters. The mountains and hills borderingalmost three-fourths of the country, along with the funnel shaped Bay of Bengal in the south,

have made the country a meeting place of life-giving monsoon rains, but also subjected it to the

catastrophic ravages of natural disasters. Its physiography and river morphology where the

mighty Brahmaputra, Ganges, Meghna and many rivers criss-cross to form a vast delta ofalluvial plains that are barely above the sea level, making it prone to flooding from waterways

swollen by rain, snowmelt from the Himalayas, and increased infiltration by the ocean, largely

contribute to recurring disasters.

A combination of geography and demography puts it among the countries that specialists predictwill be hardest hit as the earth heats up although its own carbon footprint is small. The root cause

of most of its global warming problems lies in the heavily industrialized world. Yet, as sea levels

rise only a little Bangladesh will pay a heavy price.

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Bangladesh, a densely crowded and developing small nation, contributes only a minuscule

amount to the greenhouse gases slowly smothering the planet. But the projected climate changeis likely to affect its millions of already vulnerable people. Nearly 150 million people, the

equivalent of about half the US population, live packed in an area slightly smaller than the

American State of Iowa and over 15 million of them are concentrated into the overcrowded

capital city of Dhaka. Many of them have abandoned their homes in the countryside relocating toDhaka to seek an elusive better life. Most are not successful in their quest for improved living

standards and a brighter future and live in low lying parts of the city subject to flooding and

diseases.

The main source of the majority of the people of this nation is agriculture. But an infinitesimal

rise in the sea level would submerge hundreds of acres of cultivable land as shown in the figure

below.

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All of Dhaka and most of Bangladesh lies within a mostly flat alluvial plain and many areas are

just a few feet above sea level. Violent storms regularly sweep in from the Bay of Bengal towreck havoc upon the land and inhabitants. Warmer weather and rising oceans are sending

seawater surging up Bangladesh's rivers in greater volume and frequency than ever before,

specialists say, overflowing and seeping into the soil and the water supplies of thousands of

people. Heat waves, floods, storms, cyclones, land-sliding, fires and droughts cause increaseddeaths and harm to lives and properties. On an average, river erosion takes away about 19,000

acres of land and more than one million people are directly or indirectly affected by river-bank

erosion every year in Bangladesh. Millions of people are projected to be at risk from coastalflooding due to sea level rises.

As a low lying tropical country Bangladesh is on the front line of the consequences of global

warming. Already the storms are becoming more violent. Recent heavy rainfall and many deaths

in Chittagong due to land sliding are also prior notice for alarming future. People along theshoreline have noticed a rise in the sea level. Many have already been forced to move several

times to higher ground. The planting of crops has been affected. Most crops do not fare well as

salt water moves into the water table. World Bank reported in 2001 sea level rising about 3

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mm/year in the Bay of Bengal. It warned of loss of Bengal tigers in the Sundarbans, world's

largest mangrove heritage, and threats to hundreds of its flora and fauna. The one meter sea level

rise will inundate 15 to 20 percent of Bangladesh. This means predicted sea level rise, at a ratethat is increasing, will not only affect millions of people but will also flood out much rice

production. The World Bank warned of a decline of rice crop up to 30 percent with predicted sea

level rise.

If there is an increase in temperature of 6 C, the maximum predicted by the IPCC, then thegreater flow of water through Bangladesh's three great rivers will inevitably lead to between 20

and 40 per cent more flooding. On the southern coast, erosion driven in part by accelerating

glacier melt and unusually intense rains will cause relentless sufferings to millions of people. Inthe dry northwest of the country, droughts are getting more severe. If the sea rises by a foot,

which some researchers say could happen by 2040, the resulting damage would set back

Bangladesh's progress by 30 years and up to 12 percent of the population would be madehomeless. And if sea level rises by 3 feet by the turn of the century, as some scientists predict, a

fifth of the country will disappear. As many as 30 million people would become refugees in their

own land, many of them subsistence farmers with nothing to subsist on any longer. It will result

in more density of population. If it happens, tomorrow's poverty will be far worse than today's.Bangladesh does not have preparations for the fallout of global warming as well as any capacity

or planning to go through a real challenge under climate change, biodiversity, and desertification.

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More over the climatic change has led to the changes in agricultural seasons and the monsoon

weather which the farmers are totally unaware of and they are being affected the most rising the

poverty level of such a poor nation one step high.

4.1 Lets save the world.

Globalization and industrialization is prevalent in almost every part of this world and we cannot

resist this to save the earth since it is another source of leading a prosperous and sustainable life.

The earth is feeding us, giving us room to have the joy of life, so obviously we have someresponsibilities to take care of this earth as well. The world nations must unite together to solve

the problem of global warming leaving the selfish acts. Developed nations are the biggest

contributors to global warming and emission of green house gases. They have to curb down theiruses of fossil fuels, radioactive and nuclear researches which have never done anything good to

mankind. They have to be concerned now or never about global warming and climate changes

issues and the future of the tiny nations like, Maldives, Bangladesh, and Indonesia etc.

Deforestation and extraction of natural resources for their immensely growing industrial sectorsand luxury purposes must be checked to have a sustainable life for all, present and the future

generations.

The global issues must be solved globally but what we can do personally to save the environmentand surrounding. Lets vow from now that we will use our resources efficiently and extract fullbenefit. We shall reuse, recycle and ultimate reduce the anti-environmental products. We shall

Not litter our surrounding.

Not turn on our lights when it is not needed.

Not turn the water taps and showers open while brushing or not in use.

Use more and more electricity efficient bulbs.

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Own cars that are fuel efficient and drive properly.

Avoid using products that are not biodegradable.

Reduce the use of disposable products and try to reuse them.

Be the volunteers to keep the environment clean.

Not waste our resources for decorative purposes rather go for alternatives.

Plant more and more trees to promote a green environment.

Expectations would never be met if you are unsatisfied with what you

have. Today you are living peacefully but tomorrow you may not.

Wake up from the dream, stay by my side, save the green and live the

world.

Thank You

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5.0 References:

1. www.physicalgeography.net

2. www.wikipedia.com (WIKIPEDIA the free encyclopedia)

3. www.discovery.com

4. www.channel.nationalgeographic.com

5. Google images and articles.

Division of works (According to the table of content)

Gazi Zonayet Hossain (1.1-1.5)

Kazi Mustafizur Rahman (2.1-2.1, 5.0)

Atiqur Rahman (3.1)

Purna Saha (4.1)

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