ppt on Climate Change

7/28/2019 ppt on Climate Change

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Dr. Ariful Bari Chowdhury

Lecturer, NSU

Climate Change and Its

Impact on human heal th


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Introduction to Climate science, ozone

layer depletion and climate change

Impacts of climate change

Human mitigation and adaptation

Climate change and Bangladesh

Kyoto Protocol


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Is this Possible?


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Atmosphere

The atmosphere is the thin layer of gases that

envelops Earth.

The atmosphere is composed of gas moleculesheld close to Earth's surface by a balance

between gravitation and thermal movement of

air molecules (90% of the weight of the

atmosphere is in the first 12 km above the

surface of theEarth).


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Atmosphere Composition

Major gases in the atmosphere are nitrogen(78%), oxygen (21%), argon (0.9%), and carbondioxide (0.03%).

The atmosphere also contains trace amounts ofnumerous elements and compounds, includingmethane, ozone, hydrogen sulfide, carbonmonoxide, oxides of nitrogen and sulfur,hydrocarbons, chlorofluorocarbons (CFCs), andvarious particulates or aerosols (small particles).

Water vapor is also present in the lower fewkilometers of atmosphere.


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Structure of the Atmosphere

Read the text from your book


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Atmospheric Processes Atmospheric pressure is the weight of overlying

atmosphere (air) per unit area; it decreases as altitudeincreases because there is less weight from overlyingair. At sea level, atmospheric pressure is 10 N/m2(newtons per square meter), which is equivalent to 14.7lb/in2.

Water vapor: In the lower atmosphere, water vaporcontent varies from approximately 1% to 4% by volume.The amount of water vapor present in the atmosphere ata particular location depends on many factors

Saturation point or dew point:When air holds themaximum amount of water at a given conditions. Relative humidity is a measure of how close the air is

to saturation.


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Atmospheric Processes Atmospheric pressure is the weight of overlying

atmosphere (air) per unit area; it decreases as altitudeincreases because there is less weight from overlyingair. At sea level, atmospheric pressure is 10 N/m2(newtons per square meter), which is equivalent to 14.7lb/in2.

Water vapor: In the lower atmosphere, water vaporcontent varies from approximately 1% to 4% by volume.The amount of water vapor present in the atmosphere ata particular location depends on many factors

Saturation point or dew point:When air holds themaximum amount of water at a given conditions. Relative humidity is a measure of how close the air is

to saturation.


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Surface Wind Directions

This is what surface wind

directions look like

All of these features can be

explained by uneven heating

of the Earths surface


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The Latitudinal Belts


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Climate Climate refers to the representative or characteristic

atmospheric conditions for a region on Earth. The Earthsclimate is a complex system, derived from a combination ofnatural and human induced properties, results from an interplay of radiation from the sun,

the circulation of water in oceans,

the growth of trees and other plants,

changes in land use, and

changes in the combination of gases that form the atmosphere.

Knowing the climate, we can predict a great deal about whatkinds of life we will find in an area and what kinds could survivethere if introduced.

On a regional scale, air masses that cross oceans andcontinents can have a profound influence on seasonal patternsof precipitation and temperature.

On a local scale, climatic conditions can also vary considerablyand produce a local effect referred to as a microclimate.


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Ozone in Nature

Ozone is an important natural component ofthe stratosphere.

Ozone is concentrated in a layer 12-16 miles(20-25 km) above sea level.

It is formed when high-energy ultravioletradiation splits normal oxygen (O2).

Schematic representation of the formation of stratospheric ozone.

It shields the earth from UV ray


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Chlorofluorocarbons

Chlorofluorocarbons (CFCs) were developedin the 1920s as a new class of chemicals thatwere safe, non-flammable, stable, andnonreactive.

These chemicals were very useful for

industry. The CFCs were considered ideal for

Refrigeration and air-conditioning equipment

Nontoxic propellants for aerosol cans

Blowing agents for plastic foams

Solvents and cleaning agents in the electronicsindustry


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Chlorofluorocarbons and the

Ozone Layer The stability of CFCs in the lower atmosphere

permits them to diffuse up to the stratosphere.

In the stratosphere, ultraviolet radiation breaks downthe CFC molecules, releasing atomic chlorine.

The chlorine atoms react catalytically with ozone,converting it into normal O2 oxygen.

One chlorine atom may destroy between 10,000 to100,000 ozone molecules before being washed out ofthe atmosphere.

CFCs threaten the very existence of life on ourplanet.

ppt on Climate Change

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