Topic : Topic : Case Studies of Important Scientific and Case Studies of Important Scientific and

Technological IssuesTechnological Issues

The Nature and Development of The Nature and Development of

Science and TechnologyScience and Technology

Global WarmingGlobal Warming

1. Is global warming really occurring?

Is global warming really occurring?Is global warming really occurring?

What are the evidences proving it?What are the evidences proving it?

Temperature changes in different regions Temperature changes in different regions during the past 25 yearsduring the past 25 years

Global Global temperature temperature changes in the changes in the past 140 yearspast 140 years

Temperature Temperature changes of changes of the northern the northern hemisphere hemisphere in the past in the past 1000 years1000 years

in the past 1in the past 1

Change of precipitate in different regions the past Change of precipitate in different regions the past 100 years100 years

20001860 1880 1900 1920 1940 1960 1980

14.4

14.3

14.2

14.1

14.0

13.9

13.8

13.7

13.6

13.5

57.92

57.74

57.56

57.38

57.20

57.02

56.84

56.66

56.48

56.30

C FChanges in global surface temperature

Global warming does not exist!

Although the global temperature is rising, global warming is not caused by human.

How do the scientists obtain the information?

Are the evidences from scientists reliable?

2. What are the main causes of global warming?

What are the main causes of global warming?

• Because the Sun releases more energy?

• Due to natural phenomenon?

• Maybe due to human factors?

Scientists believe of the reasons below:

• Changes of the distance between Changes of the distance between

the Earth and the Sunthe Earth and the Sun

• The amount of black spots on the SunThe amount of black spots on the Sun

• Plate tectonics movement and the change Plate tectonics movement and the change

of the landscape of the landscape

• Volcano eruption that causes Volcano eruption that causes

temperature decrease in the short-termtemperature decrease in the short-term

• Greenhouse effectGreenhouse effect

Natural

phenomenon

Man-made phenomenon

How is the Greenhouse Effect

formed?

The Greenhouse Effect

Some solar radiation is reflected by the Earth and the atmosphere.

SUN

1. Solar radiation pass through

the clearatmosphere

AtmosphereAtmosphere

EARTH2. Most radiation is ab

sorbed by the Earth’s surface and

warms it.

2. Most radiation is absorbed by

the Earth’s surface and warms it.

4. Some of the infrared radiation passes through the atmosphere, and some is re-emitted in all directions by greenhouse gas molecules. The effect of this is to warm the Earth’s surface and the lower atmosphere.

3. 3. Infrared radiation isInfrared radiation isemitted from theemitted from theEarth’s surfaceEarth’s surface

In the atmosphere, the greenhouse gases are responsible for radiation absorption

Composition of gases in the atmosphere

Major greenhouse gases• Carbon Dioxide (COCarbon Dioxide (CO22) )

• Source: Fossil fuel burning, deforestation Source: Fossil fuel burning, deforestation • Anthropogenic increase: Anthropogenic increase: 30%30%• Average atmospheric residence time:Average atmospheric residence time: 500 years 500 years

• Methane (CHMethane (CH44) ) • Source: Rice cultivation, cattle & sheep ranching, decay from Source: Rice cultivation, cattle & sheep ranching, decay from

landfills, mining landfills, mining • Anthropogenic increase: Anthropogenic increase: 145%145%• Average atmospheric residence time:Average atmospheric residence time: 7-10 years 7-10 years

• Nitrous oxide (NNitrous oxide (N22O) O) • Source: Industry and agriculture (fertilizers) Source: Industry and agriculture (fertilizers) • Anthropogenic increase: Anthropogenic increase: 15%15%• Average atmospheric residence time:Average atmospheric residence time: 140-190 years 140-190 years

Sources of Sources of

Greenhouse GasesGreenhouse Gases

Natural gases exploitationNatural gases exploitation

Burning of fossil fuelsBurning of fossil fuels

Source: OSTP

DeforestationDeforestation

Source: OSTP

Vehicle exhaust

150 100 50 0

2

0

-2

-4

-6

300

250

200

-4

-6

Thousands of years ago

Tem

per

atu

re c

han

ge

( °c

)

Car

bo

n d

ioxi

de

(pp

mv)

Temperature Change ( °c)

CO2 Concentration(Antarctic Ice Core)

CurrentLevel

Level1800AD

Atmospheric Carbon Dioxide Concentration and Temperature change

• Clear correlation between atmospheric CO2 and temperature over last 160,000 years

• Current level of CO2 is deviated from the nature

• Fast increase of CO2 is also unprecedented

• Clear correlation between atmospheric CO2 and temperature over last 160,000 years

• Current level of CO2 is deviated from the nature

• Fast increase of CO2 is also unprecedented

1 50 1 00 5 0 0

2

0

-2

-4

-6

300

250

200

400

500

600

700

750

Thousands of years ago

Tem

per

atu

re c

han

ge

( °c

)

Car

bo

n d

ioxi

de

(pp

mv)

Temperature Change through timeCompares to the present temperature

CurrentLevel

Atmospheric Carbon Dioxide Concentration and Temperature change

CurrentLevel

2100

CO2 Concentration in theatmosphere (Antarctic Ice Core)

If nothing is done to slowgreenhouse gas emissions...

• CO2 concentrations will likely be more than 700 ppm by 2100

• Global average temperatures projected to rise at 2.5 - 10.4 degrees

If nothing is done to slowgreenhouse gas emissions...

• CO2 concentrations will likely be more than 700 ppm by 2100

• Global average temperatures projected to rise at 2.5 - 10.4 degrees

3. What are the influences of global warming to us?

The influences of global warming The influences of global warming included:included:

• Individual health

• Water source

• Northern and Southern Poles

• Natural ecosystem

• Agriculture

• Forests

• Coastal areas

HealthWeather-related mortalityInfectious diseasesAir-quality respiratory illnesses

AgricultureCrop yields decreaseWorsen quality

Water ResourcesChanges in water supplyWater qualityIncreased competition for water

Coastal AreasErosion of beachesInundation of coastal landsCosts to protect coastal communities

ForestsChange in forest compositionShift geographic range of forestsForest health and productivity

Species and Natural AreasShift in ecological zonesLoss of habitat and species

Potential Climate Change ImpactsPotential Climate Change ImpactsPotential Climate Change ImpactsPotential Climate Change Impacts

Sea Level Rise

Temperature

Precipitation

• What are the measures applied to prevent global warming?

• What can we do?