GREEN HOUSE EFFECT

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*TOPIC 5. GLOBAL CLIMATE CHANGE

Essential Questions

Definitions Learning outcomes

A. How has global climate changed in the last 150 years?

B. Is climate change natural or human induced?

C. What is greenhouse effect and how does it work?

D. What is the enhanced greenhouse effect?

E. How do human activities lead to climate change?

- Climate has changed in the past through entirely natural causes.

- Human activities are impacting the climate system through increasing the amount of greenhouse gases in the atmosphere

- Explain natural causes contributing to climate change

- Explain the greenhouse effect

- Explain how various human activities have led to an increase in greenhouse gases which contribute to the enhanced greenhouse effect.

Global Warming

*Increase in global temperatures over a long period of time

Global Cooling

*Decrease in global temperatures over a long period of time

*Global Temperature changes

*5A. How has global climate changed in the last 150 years?

- Significant increases between 0.3 C and 0.6 C.

- Mean global temperatures rose faster between 1980 and 2000

*5B. Is climate change natural or human induced?

Natural factors

Variations in solar output

Volcanic eruptions

Human factors(Green house effect)

Burning fossil fuels

Deforestation

Changing land use

Agriculture

Industries

UrbanizationBecause Darren Can Always Iron Uniform

1. Variations in solar outputSun emits differing amounts of solar radiation due to changes in magnetic field

High temperaturesBecause more sunspots found Sunspots = Higher solar activity

Low temperaturesLesser sunspots foundLower solar activity

*Explain natural causes contributing to climate change

2. Volcanic eruptions

*Explain natural causes contributing to climate change

Large amount of CO2, water vapour, sulphur dioxide, dust and ash released

Results in global dimmingGradual reduction of amount of sunlight reaching the earth’s surface

Eg Mt Pinatubo in 1991Lowers temperatures for 2 years

Temporary effects on earth’s climate

http://www.youtube.com/watch?v=2QENyRWdImY

*5C. What is greenhouse effect and how does it work?5D. What is the enhanced greenhouse effect?

•Glass panels lets in light but keeps heat from escaping.

•So plants can grow with the trapped heat from the sun.

•Glass panels lets in light but keeps heat from escaping.

•So plants can grow with the trapped heat from the sun.

*Greenhouse (Cold countries)

Greenhouse effect Enhanced greenhouse effect

Definition

Natural process to trap heat

Human activities- Rapid increase in amount of greenhouse gases

Effects

Positive- Warm the earth’s

surface

Negative- Rise in global temperatures

Illustratio

n

Heat that reaches earth

Heat that are reflected back by earth & atmosphere

Heat is trapped by GH gases

Heat given out from the earth

Greenhouse gases in the atmosphere

Solar radiation from the Sun to Earth

•Greenhouse gases in atmosphere = Glass panel

•Traps heat naturally to keep Earth warm and livable

•Greenhouse gases in atmosphere = Glass panel

•Traps heat naturally to keep Earth warm and livable

Yellow layer = Extra Greenhouse Gases / Air pollutantsYellow layer = Extra Greenhouse Gases / Air pollutants

*EnhancedGreenhouseEffect

*5E. How do human activities lead to climate change?

1. Burning fossil fuels

*Fossil fuels = oil, coal and natural gas

*Burning fossil fuels produces large amount of energy

*Energy to be used for: Industries, transportation, domestic and commercial activities eg Electricity

*Contributes to carbon dioxide (results in ENHANCED greenhouse effect)

2. Deforestation

*Loss of forests due to removal or clearance of trees

*Reasons: Paper, building materials, mining, animal grazing, planting crops, infrastructure

*Results in lesser trees to absorb Carbon dioxide in the atmosphere

3. Changing land useA)Agricultur

e

-Cultivate land to produce crops and raise livestock

Produces:

-Carbon dioxide

-Nitrous Oxide

-Methane

3. Changing land use

B) Industries

-Production of goods and services eg Manufacturing

- Emission of Carbon dioxide

3. Changing land useC) Urbanisation

-Increasing number of people living in urban areas (Cities and towns)

-Fossil fuels burnt in domestic uses and transport

*Homework 5

1.Explain natural causes contributing to climate change. [2]

2.Explain the enhanced greenhouse effect. [3]

3.Explain how various human activities have led to an increase in greenhouse gases which contribute to the enhanced greenhouse effect.[3]