G LO B AL WARM IN G

G lo b a l Wa rm in g G lo b a l Wa rm in g• an average increase in the an average increase in the

temperature of the temperature of the atmosphere near the Earthatmosphere near the Earth’’s s surface and in the surface and in the troposphere1, which can troposphere1, which can contribute to contribute to changes in changes in global climate patternsglobal climate patterns

C a u s e s C a u s e s• 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. LPG,Transportation-----fuels for transports (E.g. 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)

C a u s e sC a u s e s

• 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

G lo b a l Wa rm in g G lo b a l Wa rm in g

How serious the problem is?...How serious the problem is?...

Increase in greenhouse Increase in greenhouse gasesgases• Concentration of greenhouse gases in Concentration of greenhouse gases in

the atmosphere is highly increasing by the atmosphere is highly increasing by human activitieshuman activities

→ → Leads to the increasing seriousness of global Leads to the increasing seriousness of global warmingwarming

G lo b a l s u r f a c e G lo b a l s u r f a c et e m p e r a t u r e st e m p e r a t u r e s

– increased about 0.6°C/century since increased about 0.6°C/century since the late19th centurythe late19th century

– increased to 2°C/century over the past increased to 2°C/century over the past 25 years25 years

In c r e a s e in G lo b a l In c r e a s e in G lo b a lt e m p e r a t u r e st e m p e r a t u r e s

Te m p e r a t u r e Te m p e r a t u r e d if f e r e n c e d if f e r e n c e

b e t w e e n d if f e r e n t b e t w e e n d if f e r e n t p a r t s o f p a r t s o f

a t m o s p h e r ea t m o s p h e r e• troposphere temperatures (the lowest 8 troposphere temperatures (the lowest 8 kilometers of the Earth's atmosphere) kilometers of the Earth's atmosphere) collected since 1979 also indicate warmingcollected since 1979 also indicate warming

• Cooling effect in higher parts of the Cooling effect in higher parts of the atmosphere: stratospheric temperatures atmosphere: stratospheric temperatures have been decreasing have been decreasing

N O T g lo b a lly N O T g lo b a lly u n if o rm w a rm in g u n if o rm w a rm in g

• 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.

In c r e a s in g In c r e a s in g t e m p e r a t u r e t e m p e r a t u r e

e x t r e m e se x t r e m e s• Regions that have temperatures (1-3°C) Regions that have temperatures (1-3°C)

warmer than the average: warmer than the average: – United States United States – Most of the EuropeMost of the Europe

• Regions that have temperatures (1-3°C) Regions that have temperatures (1-3°C) cooler than the average: cooler than the average: – AustraliaAustralia

R e g io n a l R e g io n a lTe m p e r a t u r e sTe m p e r a t u r e s

S e a le v e l r is in g S e a le v e l r is in g

• 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

D ir e c t D ir e c t Te m p e r a t u r e Te m p e r a t u r e

E f f e c t sE f f e c t sIncrease 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

E x t r e m e E v e n t s E x t r e m e E v e n t s

• Extreme Events: Extreme Events:

• Heat waves; Cold waves; Storms; Floods and Heat waves; Cold waves; Storms; Floods and Droughts Droughts

Global warmingGlobal warming

An increase in the frequency of extreme eventsAn increase in the frequency of extreme events

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

- C lim a t e s e n s it iv e- C lim a t e s e n s it iv ed is e a s e sd is e a s e s

• Increase the risk of some infectious diseasesIncrease the risk of some infectious diseases– [particularly that appear in warm areas; are [particularly that appear in warm areas; are

spread by mosquitoes and other insects]spread by mosquitoes and other 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 with temperatures warm (particularly in areas with polluted waters) polluted waters)

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

A ir Q u a lit y A ir Q u a lit yAn increase in the concentration of An increase in the concentration of

ground-level ozone ground-level ozone

Damage lung tissue Damage lung tissue

Harmful for those with asthma and Harmful for those with asthma and other chronic lung diseases other chronic lung diseases

F o o d s u p p ly F o o d s u p p ly

Rising temperatures and variable Rising temperatures and variable precipitation precipitation

Decrease the production of staple foods in Decrease the production of staple foods in many of the poorest regionsmany of the poorest regions

Increasing risks of malnutritionIncreasing risks of malnutrition

P o p u la t io n P o p u la t io nd is p la c e m e n td is p la c e m e n t

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 lives of the world's population now lives within 60km of the sea. within 60km of the sea.

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

U V E x p o s u r e U V E x p o s u r e( )Au s t r a lia( )Au s t r a lia

• 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 eyes No longer have transparent lenses in their eyes

U V E x p o s u r e U V E x p o s u r e( )Au s t r a lia( )Au s t r a lia• 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 proper suppress proper

functioning of the body's immune system and natural functioning of the body's immune system and natural defenses of skindefenses 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

M e a s u r e s o n M e a s u r e s o n c o n t r o ll in g t h e c o n t r o ll in g t h e

p r o b le mp r o b le m• 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 reduce the pollution produced by burning fossil fuelsthe pollution produced by burning fossil fuels

** build more build more plantsplants reduce the pollutants e.g. → reduce the pollutants e.g. →COCO22

M e a s u r e s o n M e a s u r e s o n c o n t r o ll in g t h e c o n t r o ll in g t h e

p r o b le mp r o b le m

M e a s u r e s o n M e a s u r e s o n c o n t r o ll in g t h e c o n t r o ll in g t h e

p r o b le mp r o b le m

• Citizens Citizens

** reduce the use of plastic bags as burning →reduce the use of plastic bags as burning →plastic emit CH4plastic emit CH4

* * recycle the resources, e.g. plastic recycle the resources, e.g. plastic

** reduce the use of sprays as CFCs would → reduce the use of sprays as CFCs would →be emitted outbe emitted out

M e a s u r e s o n M e a s u r e s o n c o n t r o ll in g t h e c o n t r o ll in g t h e

p r o b le mp r o b le m

** reduce the use of air-conditioner, which will reduce the use of air-conditioner, which will emit CFCsemit CFCs

* * use public transportation instead of private cars use public transportation instead of private cars reduce the pollutants emitted by cars→ reduce the pollutants emitted 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/globalissue/e_m2_2_6.htmhttp://resources.emb.gov.hk/envir-ed/text/globalissue/e_m2_2_6.htm

• http://epa.gov/climatechange/effects/index.htmlhttp://epa.gov/climatechange/effects/index.html

• http://www.tchps.edu.hk/greenweb/greenMaindGMsg5.htmhttp://www.tchps.edu.hk/greenweb/greenMaindGMsg5.htm

• http://www.ncdc.noaa.gov/oa/climate/globalwarming.htmlhttp://www.ncdc.noaa.gov/oa/climate/globalwarming.html

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