green house gases

SUBHASH S2ND SEM ENVIRONMENTAL PLANNING

SCHOOL OF PLANNING AND ARCHITECTURE NEW DELHI

INTRODUCTIONThe greenhouse effect is the

rise in temperature that the

Earth experiences because

certain gases in the

atmosphere (water vapor,

carbon dioxide, nitrous oxide,

and methane, for example)

trap energy from the sun.

Incoming Radiation

Some trace gases are known as “greenhouse" gases

because they function like the glass in a greenhouse

Incoming radiation strikes the earth and some is

absorbed

This heats the earth and the earth reradiates in the

infrared portion of the spectrum

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Greenhouse Gas Properties

Greenhouse gases absorb infrared radiation that

corresponds to the vibrational and rotational energy

levels of their bondsNormally these gases have three or more atoms.

TYPES OF GREEN HOUSE GASESCARBON DIOXIDE

METHANE

NITROUS OXIDE

CHLOROFLUROCARBONS

These gases--together with water vapor--create the natural

greenhouse effect

They trap some of the sun's energy and keep the Earth warm

enough to sustain life

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Carbon dioxide

More than 80% of carbon dioxide emissions are caused by :

Burning fossil fuels in industries

Cutting down and burning trees

Thermal power plants and automobiles.

Deforestation accounts for about 20 percent of the carbon

dioxide increase from human activities

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Deforestation

Until 50 years ago most of the carbon dioxide from

deforestation was released from temperate zones

Now tropical deforestation is the largest source

Tropical forests are being burned and cut for

farming, mining and raising cattle

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Automobile Exhaust

Burning One Gallon of Gasoline Generates 22 Pounds of

Carbon Dioxide

When gasoline is burned, the carbon in it combines with

oxygen in the air to form carbon dioxide

Because the oxygen adds weight, the newly formed

carbon dioxide weighs more than the original unburned

fuel

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Cars and Population Increase

There are over 600 million motor vehicles in the

world today

If present trends continue, the number of cars on

Earth will double in the next 30 years

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Methane

Generated naturally by bacteria ,called methanogens which is

habitat in marshes, swamp and wet land soils

It also escapes from natural gas deposits

Methane gas escapes from garbage landfills and open dumps

It also leaks out during mining, extraction and transportation of

coal, oil and natural gas

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Adding Methane

Each year we add 350 to 500 million tons of methane to

the air mainly by: Raising livestock

Coal mining and drilling for oil and natural gas

Rice cultivation

Disposing of garbage in landfills

Burning forests and fields

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New Source of Methane

In 2006, research has shown that permafrost melting

in the arctic is releasing methane trapped in formerly

frozen sediments

Permafrost melting is the result of global warming

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Potential Source of Methane

A great deal of natural gas is trapped as a solid clathrate

complex

These methane clathrates are found in bands under the coastal

sediments offshore from continents in a number of areas

They represent a possibly large new source of energy

Utilization of this resource may resource in large releases of

methane

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Animals and Methane

Bacteria in the gut of cattle break down the food these

animals eat, converting some of it to methane gas

Cattle can belch up to a half-pound of methane a day

Sheep, goats, buffalo and camels also belch methane

Rapidly growing world population produces greater demand

for meat and dairy products

Number of cattle has doubled in the past 40 years

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Nitrous Oxide

Nitrous oxide is released naturally from oceans and by bacteria

in soils

Each year we add 7 to 13 million tons of nitrous oxide to the

atmosphere mainly by:

Using nitrogen-based fertilizers

Disposing of human and animal wastes

Automobile exhausts

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Chemical Fertilizers

Nitrogen-based fertilizer use has doubled in the past

15 years

Nitrogen fertilizers provide nutrients for crops

When these fertilizers break down in the soil, nitrous

oxide is released into the air

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Sewage

Human and animal wastes release nitrous oxide

Sewage treatment plants may be a major source of

this gas

More research is needed

Animal feed lots also contribute

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Fluorocarbons

Fluorocarbons come almost entirely from human activities

They are manufactured by humans for refrigeration and other uses

Some fluorocarbons, including chlorofluorocarbons (CFCs),CFC along with

chlorine and bromine containing compounds also involve in acceleration of

ozone hole formation .

It also result in increasing the amount of hydrogen peroxide in the

atmosphere and induce acid rain

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Effect of Greenhouse Gases

Chart shows how much

warming could be caused

by each of the gases that

human activities release

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A Global Problem

An increase in global temperature would bring changes to

the entire planet, and therefore to every nation

This makes it an international issue which needs

worldwide study and responses

Individual countries are each responsible for their own

greenhouse gas production

CONSEQUENCES OF GREEN HOUSE EFFECT Global warming.

Rise in sea level flooding low lying regions.

Increase in rainfall.

Disruption of whole ecosystem.

Soil will become infertile.

Plants wll be less in N2 susceptible to pests.

CONTROLING MEASURES Reducing the consumption of fossil fuels.

Afforestation.

Eco friendly alternative CFC.

CO2 pumped into underground.

Bioremediation

Sulphate aerosols

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