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Bismark OkaikweiBismark OkaikweiUniversität BremenUniversität Bremen
9/01/089/01/08
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ContentsContents
• Brief history on greenhouse effect• The basic mechanism• What are greenhouse gases?• What makes them greenhouse gases?• How do we make greenhouse gases?• Enhanced greenhouse effect and climate change • Alternative energy• Summary
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Brief history on greenhouse effectBrief history on greenhouse effect
• It was discovered by Joseph Fourier in 1824
• But it was first investigated quantitatively by Svante Arrhenius in 1896
• He claimed that fossil fuel combustion may
eventually result in enhanced global warming
• He found that the average surface temperature of the earth is about 15ºC because of the infrared absorption capacity of water vapor and carbon dioxide
• Arrhenius suggested that a doubling of carbon dioxide concentration would lead to a 5ºC temperature rise
Joseph Fourier Svante Arrhenius
Source: www.famoussceientists.com
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The basic mechanismThe basic mechanism
• Natural gases in the earth`s atmosphere reduce the amount of heat escaping the earth into the atmosphere
• Intensity of infrared radiation increases with increasing temperature
• Average earth‘s temperature is 15ºC
Source: http://www.environment.sa.gov.au/sustainability/images/greenh
ouse_effect.jpg
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What are greenhouse gases?What are greenhouse gases?
• Water vapour (H2O)
• Carbon dioxide (CO2): The amount in the atmosphere is about 30% higher now than 200 years ago. It is the biggest contributor to the enhanced greenhouse effect (about 70%).
• Methane (CH4): The amount in the atmosphere is about 145% higher now than 200 years ago. It is the second biggest contributor to the enhanced greenhouse effect (20%).
• Nitrous Oxide (N2O): Its amount in the atmosphere is about 15% higher now than 200 years ago.
• Halocarbons: These greenhouse gases have been reduced since the phasing out of chlorofluorocarbons (CFCs) to protect the ozone layer.
• Ozone (O3)
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What makes them greenhouse gases?What makes them greenhouse gases?
• They can vibrate in the infrared region because of their symmetry and these vibrations create transient charge separation
• With such dipole moment,they can absorb and emit infrared radiation
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How do we make greenhouse gases?How do we make greenhouse gases?
• Burning of fossil fuels for energy (for electricity and fuel for transport) generates the most greenhouse gases
• Removing and burning vegetation since plants serve as greenhouse gas "sinks“
• Farming (animals particularly cattle and sheep produce methane and some fertilizers produce nitrous oxide)
• Waste breakdown
• Industry (cement and aluminium production)
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Enhaced greenhouse effect and Enhaced greenhouse effect and
climate changeclimate change • Melting of polar ice and oceanic expansion.This results in flooding of coastal
areas,swamps,wetlands and river deltas
• Increase in number and severity of tropical storms and cyclones
• Evaporation of water supplies causing drinking water scarcity
• Flooding and erosion of agricultural plots.This damages crops and soils and decreases harvest
• More extreme weather,causing hotter and drier summer and colder winters
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Alternative energyAlternative energy
• Solar power
• Wind power
• Water power
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Alternative energyAlternative energy
• Solar power (energy from the sun): new photovoltaic cells filled with silicon,however are able to take the sun‘s energy and transform it into electricity
Source: www.daviddarling.info
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Alternative energyAlternative energy
• Wind power (windmills): the power of the wind can be used to create electricity through large,wind-powered windmills called turbines
Source: www.powerhousetv.com
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Alternative energyAlternative energy
• Water power: two main ways to use water to create electricity are hydro-electricity which relies on vast volumes of water flowing down pipes and spining giant turbines and then tidal changes and waves
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SummarySummary
• The greenhouse effect describes how natural gases in the earth‘s atmosphere reduce the amount of heat escaping from the earth into the atmosphere
• The greenhouse gases are water vapor, carbon dioxide, nitrous oxide, CFCs,ozone and methane
• These gases are produced from the burning of fossil fuels, removing and burning vegetation, farming, waste breakdown and industry
• Enhanced greenhouse effect causes global warming
• Alternative energy include solar, wind and water power
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Thank you for your attentionThank you for your attention
Happy New Year to you all!!!