Global Warming & Ozone Depletion

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Global Warming

Global warming :an average increase in the temperature of

the atmosphere near the Earth’s surface and in the troposphere, which can contribute to changes in global climate patterns

global warming, the gradual increase of the temperature of the earth's lower atmosphere as a result of the increase in greenhouse gases since the Industrial Revolution.

The temperature of the atmosphere near the earth's surface is warmed through a natural process called the greenhouse effect

It is generally accepted that this increase in the quantity of greenhouse gases is trapping more heat and increasing global temperatures, making a process that has been beneficial to life potentially disruptive and harmful.

CAUSES: Burning of fossil fuels (Coal/Crude oil)

Power plants generate electricity

Transportation-----fuels for transports (E.g. LPG, kerosene, fuel oil)

Industrial processes (E.g. manufacture of cement, steel, aluminium)

Other greenhouse gases emission

Agriculture Forestry Other land uses Waste management

What are greenhouse gases?

Greenhouse Gases – trap heat in the atmosphere- examples: CO2 (carbon dioxide), methane, water vapor

The “Greenhouse Effect”- When gases reflect heat

back toward the surface of the earth- Keeps the Earth warm

The Greenhouse Effect

1. High-energy, visible light waves go through the Earth’s atmosphere.

2. As they hit the earth, they lose energy. They are released as IR (infra-red).

3. Low-energy IR waves try to leave the Earth.

4. Some IR can’t escape through the layer of greenhouse gases.

5. This trapped IR warms the Earth.

Greenhouse gases in the atmosphere

↓

Some infrared radiation is trapped

↓

Greenhouse effect

Serious greenhouse effect

Global Warming

What kind of “human activity” can cause the greenhouse effect?

adding CO2 by the burning of fossil fuels

cutting down of forests.

nitrous oxide and methane pollution

Some projected, longer-term results of global warming include

melting of polar ice, with a resulting rise in sea level and coastal flooding;

disruption of drinking water supplies dependent on snow melts;

profound changes in agriculture due to climate change;

extinction of species as ecological niches disappear;

more frequent tropical storms; and an increased incidence of tropical diseases.

Factors contributing to gw:

Among factors that may be contributing to global warming are

the burning of coal and petroleum products (sources of carbon dioxide, methane, nitrous oxide, ozone);

deforestation, which increases the amount of carbon dioxide in the atmosphere;

methane gas released in animal waste;increased cattle production, which

contributes to deforestation, methane production, use of fossil fuels

Ozone Depletion

Ozone layer=naturally occurring protective shield in the stratosphere, 25 km+ into space

absorb harmful ultraviolet radiation from the sun

protects humans, plants, and animals

• The ozone layer- helpful layer of ozone above earth’s surface; acts like a global sunscreen.

• “Ozone Holes” are caused by chlorofluorocarbons (CFC’s) (they help UV light destroy ozone)

Ozone Depletion• Ozone

Gas : molecules of 3 Oxygen atoms.

• In 1987 an international agreement, the Montreal Protocol, was reached on reducing the production of ozone-depleting compounds. Revisions in 1992 called for an end to the production of the worst of such compounds by 1996, and CFC emissions dropped dramatically by 1993. Recovery of the ozone layer, however, is expected to take 50 to 100 years. Damage to the ozone layer can also be caused by sulfuric acid droplets produced by volcanic eruptions

Environmental and Human

Effects

Direct Temperature Effects

Increase in average temperature

More extreme heat waves during the summer; Less extreme cold spells

during the winter

Harmful to those with heart problems, asthma, the elderly, the very young

and the homeless

Extreme Events

• Extreme Events: • Heat waves; Cold waves; Storms; Floods

and Droughts Global warming

An increase in the frequency of extreme events

More event-related deaths, injuries, infectious diseases, and stress-related

disorders

• Extreme Events: • Heat waves; Cold waves; Storms; Floods

and Droughts Global warming

An increase in the frequency of extreme events

More event-related deaths, injuries, infectious diseases, and stress-related

disorders

Climate-sensitive diseases

• Increase the risk of some infectious diseases

– [particularly that appear in warm areas; are spread by mosquitoes and other insects]

– E.g. Malaria, dengue fever, yellow fever, encephalitis

• Algal blooms occur more frequently as temperatures warm (particularly in areas with polluted waters)

Diseases (e.g. cholera) accompanying algal blooms become more frequent

Air QualityAn increase in the

concentration of ground-level ozone

Damage lung tissue

Harmful for those with asthma and other chronic lung

diseases

Food supply

Rising temperatures and variable precipitation

Decrease the production of staple foods in many of the poorest

regions

Increasing risks of malnutrition

Population displacement

Rising sea levels

Increase the risk of coastal flooding

(Necessitate population displacement)

• More than half of the world's population now lives within 60km of the sea.

• Most vulnerable regions: Nile delta in Egypt, the Ganges-Brahmaputra delta in Bangladesh, many small islands, such as the Maldives, the Marshall Islands and Tuvalu.

UV Exposure

• Skin Cancer  – an abnormal growth of skin tissues.

• Premature aging– make the skin thick, wrinkled, and leathery  

• Cataracts – No longer have transparent lenses in their

eyes

UV Exposure

• Other Eye Damages– Skin cancer around the eyes– Degeneration of the yellow spot

• Suppression of Immunity  – Overexposure to UV radiation suppress

proper functioning of the body's immune system and natural defenses of skin

– UV-B radiation weakens the immune system increases the chance of infection and disease

GLOBAL WARMING SOLUTIONS:

Remove carbon from the atmosphere and store it in biomass or soil

Capture carbon and store it in underground geologic formations

Produce products that reduce greenhouse gases by serving as substitutes for fossil fuels

Use electric and heating efficiency strategies to reduce greenhouse gases and save money.

A short-term solution -wind and solar produce virtually no greenhouse gases as a byproduct of power production

Improved automobile mileage, reforestation projects, energy efficiency in construction,

and national support for mass transit are

among relatively simpler adjustments that could significantly lower production of greenhouse gases.

More aggressive adjustments include a gradual worldwide shift away from the use of fossil fuels,

the elimination of chlorofluorocarbons, and

the slowing of deforestation by restructuring the economies of developing nations.

Facts:

In 1992, at the United Nations Conference on Environment and Development, over 150 nations signed a binding declaration on the need to reduce global warming.

A UN Conference on Climate Change, held in Kyoto, Japan, in 1997 resulted in an international agreement to fight global warming, which called for reductions in emissions of greenhouse gases by industrialized nations.

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