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 troposphere, which can troposphere, 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, aluminum)cement, steel, aluminum)

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 CO2CO2 + 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 temperature.Increase 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 homeless.the 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

regions.regions.

Increasing risks of malnutrition.Increasing risks of malnutrition.

Population Population displacementdisplacement

Rising sea levels. Rising sea levels.

Increase the risk of coastal flooding.Increase 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 to limit the amount of pollutants produced by amount of pollutants produced by factoriesfactories

* * Develop the Develop the skills of using skills of using renewable fuelsrenewable fuels, e.g. solar , e.g. solar energy, wind energyenergy, wind energy

** E Encourage the factories to ncourage 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

** C Carry out arry out energy saving scheme → energy saving scheme → reduce the pollution produced by burning reduce the pollution produced by burning fossil fuelsfossil fuels

** B Build more uild 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

** R Reduce the use of plastic bags → as educe the use of plastic bags → as burning plastic emit CH4burning plastic emit CH4

* R* Recycle the resources, e.g. plastic ecycle 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

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