Topic : Case Studies of Important Scientific and Technological Issues The Nature and Development of...
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Transcript of Topic : Case Studies of Important Scientific and Technological Issues The Nature and Development of...
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
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?
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
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
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
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