ATMOSPHERE

LAYER OF GASES ENGULFING THE PLANET EARTH

05/31/12 2

The biosphere is that layer of earth that supports life.

Floors of the ocean to the tops of the highest mountains.

All together, it is about 20 kilometres thick.

However most organisms live in a very narrow range.

05/31/12 3

Deep below the ocean life is rare because the pressure is too high for most organisms.

Few organisms live high upon the tallest mountains, because the oxygen is too thin and temperatures are too cold.

Most life on the earth exists between 500 meters below the surface of the ocean and about 6 kilometres above sea level.

05/31/12 4

Within the biosphere, organisms live in a wide variety of environments.

The biosphere provides all organisms with the materials they need to live.

For example, we live on the lithosphere, but breathe the air of the atmosphere and drink the water of the hydrosphere.

05/31/12 5

Weather is the condition of the atmosphere at a particular place and time measured in terms of wind, temperature, humidity, atmospheric pressure, cloudiness, and precipitation (rain, snow, etc.).

At most places, weather can change from hour-to-hour, day-to-day and season-to-season.

05/31/12 6

Climate is the average pattern of weather in a place.

For example:Thar Desert has a “warm climate” which means temperatures are generally higher in summer, there is limited rainfall, and humidity is typically low.

05/31/12 7

Climate has a big influence on plants and animals in the natural environment, on oceans, and on human activities, such as agriculture, water supplies, and heating and cooling.

The effects of climate change depend upon how much change there is?

How fast it occurs, and how easily the world can adapt to the new conditions.

05/31/12 8

Effects of climate change on people would change a lot from place-to-place.

Economically developed societies, like those in North America, Europe and Japan, could use technology to reduce direct impacts.

For example, they might develop new crop varieties, construct new water systems, and limit coastal development.

Some northern countries, such as Canada and Russia, might even benefit from longer growing seasons and lower heating bills if the climate becomes warmer.

05/31/12 9

In contrast, economically less developed societies, like those in parts of Africa, Asia, and South America depend much more directly on climate, and could be hit much harder by sudden or large changes.

Places like coastal Bangladesh and low-lying islands, could be flooded by storms or rising sea level.

Droughts in Africa might become more serious.

05/31/12 10

Developing countries have far fewer resources for adapting to such changes.

They may not be able to afford large projects such as sea walls.

Farmers may have difficulty adopting new agricultural practices.

The resulting social tensions could lead to more political unrest, large-scale migrations, and serious international problems such as terrorism and wars.

05/31/12 11

When scientists look at the past they find the natural environment has often adapted to climate changes that have occurred gradually over many thousands of years.

However, they also find instances in which changes have occurred rapidly, brought about by events such as sudden shifts in ocean currents.

These rapid changes have often caused widespread species extinctions and the collapse of natural ecosystems.

05/31/12 12

Changes in insect pests: Climate change can affect the number and kinds of pests

It can also affect them by changing the mix of plant varieties and their nutrient content.

This can influence plant survival, food chains, and the spread of disease.

Mangrove swamps: Mangrove swamps are important breeding grounds for many animals that live in water.

Increased ocean flooding may damage these areas by changing the supply of nutrients and the amount of salt.

05/31/12 13

Abatement: To abate means to slow or stop.

Abatement strategies aim to reduce the emissions of carbon dioxide and other gases that can cause climate change.

They include improving energy efficiency, so that we burn less fuel, and using sources of energy that emit no greenhouse gases, such as solar or nuclear power.

05/31/12 14

Adaptation: Under this strategy people find ways to live successfully with the changed climate.

For example, land use may change. Aqueducts can be built to bring water into newly dry areas.

Coastal populations can be protected from rising sea level by building dikes and sea walls, by relocating populations inland, and by protecting fresh-water supplies from salt-water intrusion.

05/31/12 15

Most Effective Actions Since most of our energy comes from oil, coal and gas, actions that reduce energy use will reduce the emissions of carbon dioxide. For example:

When you buy a car, choose one that gets good mileage.

05/31/12 16

Insulate and weatherise your home or apartment.

Carpool or drive less. Replace old, worn-out appliances (e.g., refrigerators, heat pumps) with the most efficient new models.

If the average citizen undertakes all of these actions, they can reduce their carbon dioxide emissions by about 25%.

05/31/12 17

Turn off lights and appliances when not needed.

Plant trees. Recycle. If the average citizen undertakes all of these actions, they can reduce their carbon dioxide emissions by about 3%, which equals just over half a ton of carbon dioxide per year.

05/31/12 18

Become informed and help your family and friends to learn about climate change.

Actively support the government policies that are most appropriate.

05/31/12 19

Improve energy efficiency: More efficient cars, appliances, and industrial

systems use less energy, which means that less fuel is burned and less carbon dioxide is emitted.

Substantial energy efficiency improvements can be obtained by replacing individual devices.

In the longer run, even larger savings may be possible through structural changes, such as being able to work closer to home or redesigning the way houses and cities are built.

05/31/12 20

Develop and use energy sources that emit little or no carbon dioxide:

Hydropower, solar power and windmills, as well as other "renewable energy" sources, emit no carbon dioxide.

Neither does nuclear power. Burning natural gas emits less carbon dioxide

than burning coal or oil. In the future, hydrogen, which emits no carbon

dioxide when it is burned, may become a practical fuel.

Ways of capturing and storing carbon dioxide might also be developed.

05/31/12 21

Improve forest and agricultural management practices:

Trees remove carbon dioxide from the atmosphere and store it in wood.

Methane produced by some agricultural activities, such as raising cattle, landfills and rice farming, can be reduced.

05/31/12 22

Reduce the impacts of climate change: New varieties of crops can be developed to grow in changed climates.

Aqueducts can carry water to regions affected by drought.

Coastal settlements and water supplies can be protected from rising sea level with dikes and sea walls.

Coastal ecosystems, especially wetlands, are harder to protect.

05/31/12 23

Government regulation: Government can require desired behaviors (e.g., force auto companies to build more efficient cars).

An advantage of regulation is that it specifies the desired outcomes and can force action.

However, regulation can be inflexible and discourage innovation.

05/31/12 24

Prices and markets: Higher prices for fossil fuels encourage people to save energy by promoting energy efficient devices and behavior (e.g., expensive gas prompts companies to make and people to buy more fuel efficient cars).

An advantage of using prices is that they present a constant incentive to innovate.

However, using prices can have undesirable side effects, such as imposing a relatively larger burden on the poor.

05/31/12 25

Information and education: People often do not know how to improve efficiency or reduce emissions.

Government can provide them with the information they need to make better choices.

Research and development: Government and industry can support research to demonstrate and improve existing technology, and to develop new technologies that use less energy or emit no carbon dioxide.

For example: refrigerators that use less electricity, cheap solar water heaters, and inexpensive solar/hydrogen technology).

05/31/12 26

The atmosphere covers the entire globe and climate affects everyone.

If abatement strategies are to be effective they will require international cooperation.

Until now, developed countries have been the major sources of emissions.

In the future, large developing countries, such as China, will be an increasingly important source of emissions.

05/31/12 27

These countries argue that if the world must reduce emissions of carbon dioxide and other greenhouse gases, the U.S., Europe, and Japan should reduce the most.

For years, they argue, these developed countries have been the largest emitters and they have already enjoyed the associated benefits of economic development.

While this is true, developing countries could also help by doing more to control population growth.

05/31/12 28

Rate at which the composition of the atmosphere is altered through human actions has accelerated in recent decades.

The level of CO2, CH4, N2O, O3, CFC’s, and other greenhouse gases released by human industrial, agricultural and forestry activities are building up in the troposphere.

There is strong scientific consensus that if current trends continue, the build up of these gases is likely to cause significant warming of the global climate.

Some warming may already be inevitable because of past emissions.

05/31/12 29

S. No.

Gas Pre industrial

1996 Present Annual Rate of Increase (Percent)

1 CO2 275 ppm 346 ppm 1.4 ppm (0.4)

2 CH4 0.75 ppm 1.65 ppm 17 ppb (1.0)

3 CFC’s-11 0.00 400 ppt 19 ppt (5.0)

4 CFC’s-12 0.00 230 ppt 11 ppt (5.0)

5 N2O 280 ppb 305 ppt 0.6 ppb (0.2)

6 O3 Unknown 35 ppb Unknown

05/31/12 30

The effects of a climate change resulting in global warming over the half century are likely to include:

A rise in sea level of perhaps 30 cm Changes in winds Changes in ocean currents

05/31/12 31

Melting of polar ice caps & the frequency of storms

Variations in the range of disease – bearing organisms and other impacts on public health

Alterations in precipitation patterns that will affect water availability and agriculture

Changes in wetlands, forests and other natural ecosystems, possibly leading to the increased extinction of plant and animal species

05/31/12 32

The carbon dioxide has received the most attention.

The studies indicate that the contribution of major greenhouse gases is:

Carbon dioxide ----------- > 50 % Chlorofluorocarbons ----------- > 20 % Methane ----------- > 16 % Tropospheric Ozone ----------- > 08 % Nitrous Oxide ----------- > 06 %

05/31/12 33

1. Equatorial Zone0o – 10o North – South Latitude: Diurnal Variation in temperature is greater than seasonal.

2. Tropical Zone10o – 30o North – South: Clear Season, rains in summer season.

3. Sub – Tropical ZonePole ward 30o North – South: Rainfall very low, temperature very high in summer.

05/31/12 34

4. Transitional ZoneAround 40o: In summer it belongs to high-

pressure zone and in winter it receives cyclonic rains.

5. TEMPERATURE ZONES Warm Temperate Zone Typical Temperate Zone Cold Temperate Zone Arctic Climate Zone

05/31/12 35

Tropical Ever Green Rain Forests Tropical moist and dry Deciduous

Forests (Australia, Africa) Sub – Tropical deserts & Semi

deserts (North America, Chile, Peru, Arabian

states, Indian and Iranian desert)

05/31/12 36

Warm temperature wet Ever Green Forests (East Asia, New Zealand)

Deciduous Forests of Temperate Zone (North America, Central Europe, East Asia)

Conifer Zone (North America, Eurasia)

Tundra Zone (Pole in Arctic Climate Zone, tip of South America)

05/31/12 37