Download The Atmosphere - global warming

The Atmosphere - global warming
L2
English in Natural Science
自然科学の英語
2006
自然科学の英語-ENS-L2
2006
自然科学の英語-ENS-L2
Vertical structure
• Density decreases with
altitude
– gravitational force
• Layers of different
composition
– Homosphere (90 km)
– Heterosphere
Mass
90 km
Mesosphere
Heterosphere
Homosphere
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< 1%
48 km
Stratosphere
Ozone layer
14%
Troposphere
85%
12 km
自然科学の英語-ENS-L2
Ozone layer
• Filter (15-40 km) against UV solar radiation
90% ozone
[O3] 2-8 ppm
• Destruction by CFC:
CFCl3 + hv CFCl3 + Cl
O3 + Cl  O2 + ClO
Effects
1. Increased UV radiation
 DNA damage
(mutations, cancer)
2. Less absorption
of radiation
 Air cooling
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自然科学の英語-ENS-L2
Ar CO2
1%
Troposphere
• Current composition
–
–
–
–
–
other
O2
21%
N2 (78.08%)
O2 (20.95%)
Ar (0.93%)
CO2 (0.035%)
Other (0.005%)
N2
78%
• Ne, He, CH4, Kr, NO2-, H, Xe, O3
• Temperature decreases with altitude
– average 1 oC for 100 m
surface ~15 oC  1,500 m water condensates
– Clouds form between 1500-3000 m
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自然科学の英語-ENS-L2
Evolution of atmosphere
78% N2
21% O2
<1% CO2
95% N2
3.5% CO2
<1% O2
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自然科学の英語-ENS-L2
Atmosphere is dynamic
• Solar powered
• Convection
– Hot air UP
– Cold air DOWN
• Circulation routes
– west  east
– tropics  poles
• Jet streams
• Effects:
– Mixing of gasses
– Temperature buffer
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自然科学の英語-ENS-L2
Coriolis effect
• Rotation of the Earth
– Air moves inward in
circles  cyclons
– Inertial circles
C
Centrifugal
force
Tropical cyclon
台風typhoon
hurricane
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Hydrological cycle
Energy  Sun
Water on Earth
• Oceans (97%)
– Salty water
• Atmosphere
– Evaporation (H2O vapour)
– Condensation (cloud)
– Precipitation (rain)
Evapotranspiration
• Land
– Snow  icecaps  water
– Runoff  rivers
• Dissolves materials
• Erosion of land
– Evapotranspiration (plants)
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The Blue Planet
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Hydrosphere - water distribution
Location
Volume (km3)
Percentage
Oceans
1,322,000,000
97.2
29,200,000
2.15
8,630,000
0.635
Ground water
8,400,000
0.62
Freshwater lakes
125,000
0.009
Saline lakes/seas
104,000
0.008
Soil moisture
67,000
0.005
Atmosphere
13,000
0.001
Rivers
1,250
0.0001
1,360,000,000
100.0
Icecaps + glaciers
Water on land
World total
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自然科学の英語-ENS-L2
Interaction atmosphere - hydrosphere
• Solar radiation
– Water evaporation (oceans)  condensation
(clouds)
– Hot air UP and cold air DOWN
• Earth’s rotation
– Air + clouds move in inertial circles (cyclons)
• Earth’s topography (e.g. mountains)
– Distort movement of cyclons
– Cause precipitation (rain)
– Region  different weather pattern
CLIMATE
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自然科学の英語-ENS-L2
Climate patterns
Koeppen System
1st level: latitude zone
•
•
•
•
•
Tropical
Subtropical
Temperate
Polar
Mountain/highland
2nd level: precipitation
• Regular throughout year
• Dry winter
• Dry summer
3rd level: temperature
•
•
•
•
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Hot
Mild
Cool
Cold
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• Cs: Mediterranean (dry summer subtropical)
Af: Tropical Rainforest
• Cfa: Humid Subtropical
Aw: Tropical Wet & Dry
• CFb: Marine West Coast
(Savanna)
• Df & Dw: Humid Continental & Subarctic
• BSh: Tropical Steppe
• ET: Tundra
• BWh: Tropical Desert
• BSk & BWk: Midlatitude Steppe & • Highland
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自然科学の英語-ENS-L2
Desert
•
•
Climate change: Causes
• Weather changes - short term cycles
– Sun spots fluctuations (11 yr period)
– Sea-temperature currents (El Niño oscillations)
• Climate changes - long-term oscillations
– Solar radiation (insolation)
• Precession of equinoxes (23,000 yr period)
• Tilt (1o) of Earth’s rotational axis (41,000 yr period)
• Eccentricity cycle (100,000 and 400,000 yr period)
Milankovitch cycles
– Carbon dioxide and methane in atmosphere
• Biomass amount and distribution
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自然科学の英語-ENS-L2
Climate indicators
•
 ice-sheet thickness
 sea level
• 13C  biomass (productivity)
• CO2  atmospheric temperature
 carbonate deposition/dissolution
• CH4  wetland expansion/reduction
 monsoonal precipitation
2006
18O
自然科学の英語-ENS-L2
Weather cycles
Temperature cycles
11 x 2 yr period
Southern
Oscillation Index
(El Niño)
• cold  dryness
• warm  rainfall
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Humdbolt
Current
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Astronomic variations
 insolation
Axial tilt
Polaris<-->Vega
Orbit
eccentricity
Precession
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Holocene (10,000 yr)
• Insolation
– perihelion from July to January
– 8% more insolation summer and less in winter NH
• Effects
– Global ice-volume decreased (18O from 15,000 to
6,000 yr)
– Sea-surface temperature up (8 oC Atlantic winter)
– Sea level up (100 m)
• CO2 increased
– 200 ppm (15,000 yr)  250 ppm (6,000 yr)
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自然科学の英語-ENS-L2
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自然科学の英語-ENS-L2
Pleistocene (175,000 yr)
• Insolation
– superimposition 23, 41 and 100 year cycles
• Effects
– Ice-sheet (18O)
– Sea-level
– CO2
– methane
– Monsoon (SE Asia)
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自然科学の英語-ENS-L2
Quaternary (3 million yr)
• Directly related to insolation cycles
• Patterns of variation
– Several ice-age periods
– Cooling trend in last 700,000 yr
– Changes in biomass (productivity)
– Irreversible variations due to continental drift
• Mountain uplift regulate the magnitude of monsoonal
oscillations
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自然科学の英語-ENS-L2
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自然科学の英語-ENS-L2
(Webb and Bartlein, 1992)
Greenhouse gasses
• Transparent to incoming solar radiation
• Absorb outgoing infrared radiation (l > 0.78 mm) emitted
by Earth (surface + atmosphere)
CO2
CH4
NO2
CFC
Radiative forcing
W/m2 relative
1.56
1
0.5
58
0.1
206
0.3
3970
5750
CO2
CH4
+36%
NO2
CFC
+20%
2006
+150%
自然科学の英語-ENS-L2
Carbon dioxide (CO2) and temperature
Antarctica
Vostok lake
(160,000 yr)
What causes
CO2 cycles?
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自然科学の英語-ENS-L2
(Barnola et al., 1987)
Current CO2 in atmosphere
• Sources
• Atmospheric CO2
– Initially (3.5 bya) 100 x
– Reduction…
• Biomass
• Carbonate deposition
– 98% natural
• Biological
• Volcanic eruptions
– 2% human activities
– Now 300 Gt (x109 tons)
• Upward trend
Before 1800
1800
2004
Total increase
Current rate
2006
Keeling curve
190-290 ppm
280 ppm
380 ppm
+36%
1.8 ppm/yr
自然科学の英語-ENS-L2
Human impact on the carbon cycle
Sources of CO2
6-8 Gt/year (1995)
– Emissions (83%)
• Fossil fuels (CO2, CH4)
• Fertilizers (NO2)
– Deforestation (17%)
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自然科学の英語-ENS-L2
6.5 Gt
0.140 Gt
0.4 m Km2/year
36,000 Km2 Amazon
Carbon balance
44%
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自然科学の英語-ENS-L2
36%
20%
Effects: global warming
• Average air temperature increased
I) 0.7 oC in 30 yr
ii) 2003 heat wave
in Europe
94 mt harvest lost
(5% world grain)
2006
自然科学の英語-ENS-L2
Effects in the
ocean…
…start to be
felt.
• Sea levels in
Gulf of Mexico
• Wild weather
– Katrina, Rita
– Japan 2004
(11 typhoons)
2006
自然科学の英語-ENS-L2
Global climatic impact of CO2
• Global warming
[CO2] UP  Temperature UP
Temperature
– Air:
more H2O vapour  rainfall increase
pressure  wild weather (typhoon)
– Water: melting icecaps  increase sea levels
[CO2]
– Air:
photosynthesis UP  more plant biomass
– Water: dissolved CO3-2  coral and marine plankton
• Ice-age
[CO2] DOWN  Temperature DOWN
– Air:
less H2O vapour  rainfall decrease
dryness  dust UP  less radiation (cooling)
– Water: icecaps increase  decrease sea levels
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自然科学の英語-ENS-L2
Alternating warm/cold cycles
Warm
periods
Iceage
[CO2]
[CO2]
Temp
Temp
Ice
Vegetation
Ice
Vegetation
[HCO3-]
dissolve
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[CO3-2]
[HCO3-]
[CO3-2]
[CO3Ca•Mg]
[CO3Ca•Mg]
自然科学の英語-ENS-L2
precipitate
References
• Schneider, S. H. 1989. The greenhouse effect:
Science and policy. Science 243: 771-81.
• Webb III, T. and Bartlein, P.J. 1992. Global changes
during the last 3 million years: Climatic controls and
biotic responses. Annu. Rev. Ecol. Syst. 23: 141-173
• Wuebbles, D.J. and Jain, A.K. 2001. Concerns about
climate change and the role of fossil fuel use. Fuel
Proces. Technol. 71: 99-119
• Feely R.A. et al.2004. Impact of anthropogenic CO2
on the CaCO3 system in the oceans. Science 305:
362-366
2006
自然科学の英語-ENS-L2