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GLOBAL WARMING
Global WarmingGlobal Warming• an average increase in an average increase in
the temperature of the the temperature of the atmosphere near the atmosphere near the EarthEarth’’s surface and in the s surface and in the troposphere1, which can troposphere1, which can contribute to contribute to changes in changes in global climate global climate patternspatterns
Causes Causes • Burning of fossil fuels (Coal/Crude oil)Burning of fossil fuels (Coal/Crude oil)
– Power plantsPower plants generate electricity generate electricity
– Transportation-----fuels for transports (E.g. Transportation-----fuels for transports (E.g. LPG,LPG,
kerosene, fuel oil)kerosene, fuel oil)
– Industrial processes (E.g. manufacture of Industrial processes (E.g. manufacture of cement, steel, aluminium)cement, steel, aluminium)
CausesCauses
• Other greenhouse Other greenhouse gases emissiongases emission
– AgricultureAgriculture– ForestryForestry– Other land usesOther land uses– Waste managementWaste management
Besides carbon dioxide,
other gases such as
methane,
chlorofluorocarbons, nitrogen
oxides and ozone also
contribute to the greenhouse
effect.
Example : Using natural gas to cookExample : Using natural gas to cook
CHCH4 4 + 2O+ 2O22 COCO22 + 2H+ 2H22OO
Greenhouse gases in the atmosphereGreenhouse gases in the atmosphere
↓↓
Some infrared radiation is trapped Some infrared radiation is trapped
↓↓
Greenhouse effectGreenhouse effect
Serious greenhouse effect
Global WarmingGlobal Warming
How serious the problem How serious the problem is?...is?...
Increase in greenhouse Increase in greenhouse gasesgases• Concentration of greenhouse gases Concentration of greenhouse gases
in the atmosphere is highly in the atmosphere is highly increasing by human activitiesincreasing by human activities
→ → Leads to the increasing seriousness of Leads to the increasing seriousness of global warmingglobal warming
Global surface Global surface temperaturestemperatures
– increased about 0.6°C/century increased about 0.6°C/century since the late19th centurysince the late19th century
– increased to 2°C/century over the increased to 2°C/century over the past 25 yearspast 25 years
Increase in Global Increase in Global temperaturestemperatures
Temperature Temperature difference between difference between different parts of different parts of atmosphereatmosphere• troposphere temperatures (the troposphere temperatures (the
lowest 8 kilometers of the Earth's lowest 8 kilometers of the Earth's atmosphere) collected since 1979 atmosphere) collected since 1979 also indicate warmingalso indicate warming
• Cooling effect in higher parts of the Cooling effect in higher parts of the atmosphere: stratospheric atmosphere: stratospheric temperatures have been decreasing temperatures have been decreasing
NOT globally uniform NOT globally uniform warmingwarming • Warming parts:Warming parts:
– North America North America – Eurasia Eurasia
• Cooling parts:Cooling parts:– parts of the southeastern U.S.parts of the southeastern U.S.
Increasing temperature Increasing temperature extremesextremes• Regions that have temperatures (1-Regions that have temperatures (1-
3°C) warmer than the average: 3°C) warmer than the average: – United States United States – Most of the EuropeMost of the Europe
• Regions that have temperatures (1-Regions that have temperatures (1-3°C) cooler than the average: 3°C) cooler than the average: – AustraliaAustralia
Regional Regional TemperaturesTemperatures
Sea level risingSea level rising
• rising at an average rate of 1 - 2 rising at an average rate of 1 - 2
mm/year over the past 100 years mm/year over the past 100 years
Environmental Environmental and Human and Human
EffectsEffects
Direct Temperature Direct Temperature EffectsEffects
Increase in average temperatureIncrease in average temperature
More extreme heat waves during the More extreme heat waves during the summer; Less extreme cold spells during summer; Less extreme cold spells during
the winter the winter
Harmful to those with heart problems, Harmful to those with heart problems, asthma, the elderly, the very young and asthma, the elderly, the very young and
the homelessthe homeless
Extreme EventsExtreme Events
• Extreme Events: Extreme Events:
• Heat waves; Cold waves; Storms; Floods Heat waves; Cold waves; Storms; Floods and Droughts and Droughts
Global warmingGlobal warming
An increase in the frequency of extreme An increase in the frequency of extreme eventsevents
More event-related deaths, injuries, infectious More event-related deaths, injuries, infectious diseases, and stress-related disordersdiseases, and stress-related disorders
• Extreme Events: Extreme Events:
• Heat waves; Cold waves; Storms; Floods Heat waves; Cold waves; Storms; Floods and Droughts and Droughts
Global warmingGlobal warming
An increase in the frequency of extreme An increase in the frequency of extreme eventsevents
More event-related deaths, injuries, infectious More event-related deaths, injuries, infectious diseases, and stress-related disordersdiseases, and stress-related disorders
Climate-sensitive Climate-sensitive diseasesdiseases• Increase the risk of some infectious diseasesIncrease the risk of some infectious diseases
– [particularly that appear in warm areas; [particularly that appear in warm areas; are spread by mosquitoes and other are spread by mosquitoes and other insects]insects]
– E.g. Malaria, dengue fever, yellow fever, E.g. Malaria, dengue fever, yellow fever, encephalitis encephalitis
• Algal blooms occur more frequently as Algal blooms occur more frequently as temperatures warm (particularly in areas temperatures warm (particularly in areas with polluted waters) with polluted waters)
Diseases (e.g. cholera) accompanying algal Diseases (e.g. cholera) accompanying algal blooms become more frequentblooms become more frequent
Air QualityAir QualityAn increase in the concentration An increase in the concentration
of ground-level ozone of ground-level ozone
Damage lung tissue Damage lung tissue
Harmful for those with asthma Harmful for those with asthma and other chronic lung and other chronic lung
diseases diseases
Food supplyFood supply
Rising temperatures and variable Rising temperatures and variable precipitation precipitation
Decrease the production of staple Decrease the production of staple foods in many of the poorest foods in many of the poorest
regionsregions
Increasing risks of malnutritionIncreasing risks of malnutrition
Population Population displacementdisplacement
Rising sea levels Rising sea levels
Increase the risk of coastal floodingIncrease the risk of coastal flooding
(Necessitate population displacement) (Necessitate population displacement)
• More than halfMore than half of the world's population now of the world's population now lives within 60km of the sea. lives within 60km of the sea.
• Most vulnerable regions: Nile delta in Egypt, the Most vulnerable regions: Nile delta in Egypt, the Ganges-Brahmaputra delta in Bangladesh, many Ganges-Brahmaputra delta in Bangladesh, many small islands, such as the Maldives, the Marshall small islands, such as the Maldives, the Marshall Islands and Tuvalu. Islands and Tuvalu.
UV Exposure UV Exposure (Australia)(Australia)
• Skin CancerSkin Cancer – an abnormal growth of skin tissues. an abnormal growth of skin tissues.
• Premature agingPremature aging– make the skin thick, wrinkled, and leathery make the skin thick, wrinkled, and leathery
• CataractsCataracts – No longer have transparent lenses in their No longer have transparent lenses in their
eyes eyes
UV Exposure UV Exposure (Australia)(Australia)• Other Eye DamagesOther Eye Damages
– Skin cancer around the eyesSkin cancer around the eyes– Degeneration of the yellow spotDegeneration of the yellow spot
• Suppression of ImmunitySuppression of Immunity – Overexposure to UV radiation Overexposure to UV radiation suppress suppress
proper functioning of the body's immune proper functioning of the body's immune system and natural defenses of skinsystem and natural defenses of skin
– UV-B radiation weakens the immune system UV-B radiation weakens the immune system increases the chance of infection and diseaseincreases the chance of infection and disease
Measures on controlling Measures on controlling the problemthe problem
• GovernmentGovernment
* * set some set some lawslaws to limit the amount of to limit the amount of pollutants produced by factoriespollutants produced by factories
* * develop the develop the skills of using skills of using renewable fuelsrenewable fuels, e.g. solar energy, , e.g. solar energy, wind energywind energy
** encourage the factories to encourage the factories to replace fossil replace fossil fuelsfuels by renewable fuels, which would not by renewable fuels, which would not cause environmental pollutioncause environmental pollution
** carry out carry out energy saving scheme → energy saving scheme → reduce the pollution produced by burning reduce the pollution produced by burning fossil fuelsfossil fuels
** build more build more plantsplants → reduce the → reduce the pollutants e.g. COpollutants e.g. CO22
Measures on controlling Measures on controlling the problemthe problem
Measures on controlling Measures on controlling the problemthe problem
• Citizens Citizens
** reduce the use of plastic bags → as reduce the use of plastic bags → as burning plastic emit CH4burning plastic emit CH4
* * recycle the resources, e.g. plastic recycle the resources, e.g. plastic
** reduce the use of sprays → as CFCs reduce the use of sprays → as CFCs would be emitted outwould be emitted out
Measures on controlling Measures on controlling the problemthe problem
** reduce the use of air-conditioner, which reduce the use of air-conditioner, which will emit CFCswill emit CFCs
* * use public transportation instead of use public transportation instead of private cars → reduce the pollutants private cars → reduce the pollutants emitted by carsemitted by cars
SourcesSources
• http://www.who.int/globalchange/climate/en/http://www.who.int/globalchange/climate/en/
• http://resources.emb.gov.hk/envir-ed/text/http://resources.emb.gov.hk/envir-ed/text/globalissue/e_m2_2_6.htmglobalissue/e_m2_2_6.htm
• http://epa.gov/climatechange/effects/http://epa.gov/climatechange/effects/index.htmlindex.html
• http://www.tchps.edu.hk/greenweb/http://www.tchps.edu.hk/greenweb/greenMaindGMsg5.htmgreenMaindGMsg5.htm
• http://www.ncdc.noaa.gov/oa/climate/http://www.ncdc.noaa.gov/oa/climate/globalwarming.htmlglobalwarming.html
THE END