Ch. 19
Climate Disruption & Ozone Depletion
How Might the Earth’s Temperature & Climate Change in
the Future? * Considerable scientific evidence indicates that the earth’s atmosphere is warming, because of a combination of natural effects and human activities, and that this warming is likely to lead to significant climate disruption during this century.
Weather & Climate Are Not The Same
Weather• Short-term changes
in atmospheric variables in given area over a period of hours/days
• Temperature• Precipitation• Wind• Barometric
Pressure
Climate• Average weather
conditions of a particular area over long period of time (decades, centuries, thousands of years)
• Temperature• Precipitation
Minimum Period = 3 decades
Climate Change is NOT New
Over the past 4.7 billion years the climate has been altered by– Volcanic emissions
Climate Change is NOT New
Over the past 4.7 billion years the climate has been altered by– Changes in solar input
Climate Change is NOT New
Over the past 4.7 billion years the climate has been altered by–Movement of the continents
Climate Change is NOT New
Over the past 4.7 billion years the climate has been altered by– Impacts by meteors
Climate Change is NOT New
Over the past 4.7 billion years the climate has been altered by– Changing global air and ocean
circulation
Climate Change is NOT New
Over the past 900,000 years– Glacial and interglacial periods
Climate Change is NOT New
• Over the past 10,000 years– Interglacial period
• Over the past 1,000 years– Temperature stable
• Over the past 100 years– Temperature changes; methods of
determination
Estimated Changes in the Average Global Temperature of
the Atmosphere
Fig. 19-2, p. 494
Fig. 19-2a, p. 494
17
Aver
age
surf
ace
tem
pera
ture
(°C)
800 700 600 500 400 300 200 100
Thousands of years ago
16
14
910
11
12
13
15
900 Present
Fig. 19-2b, p. 494
15.0
Aver
age
surf
ace
tem
pera
ture
(°C)
1880 1900 1920 1940 1960 1980 2000 2020
Year
14.8
14.6
14.4
14.2
14.0
13.8
13.6
*
Fig. 19-2c, p. 494
TEMPERATURE CHANGE (over past 22,000 years)
2
1Agriculture established
End of last ice age-2
Average temperature over past 10,000 years = 15°C (59°F)
-4Tem
pera
ture
cha
nge
(°C)
20,000 2,000 200 100 Now
Years ago
0
-1
-3
-5
10,000 1,000
Fig. 19-2d, p. 494
0.5
0.0
-0.5
Tem
pera
ture
cha
nge
(°C)
-1.0
1000 1100 1200 1300 1400 1500 1600 1700 1800 1900 2000 2100Year
How do we know past changes in temperature?
• Radioisotopes in rocks & fossils• Plankton & radioisotopes in ocean
sediments• Pollen from lake bottoms• Ice cores from ancient glaciers• Tree rings• Radioisotopes in corals• Historic record – since 1861• Temperature measurements
Ice Cores Are Extracted by Drilling Deep Holes in Ancient Glaciers*
Fig. 19-3, p. 495
The Natural Greenhouse Effect(tropospheric heating effect)*
Greenhouse Gases (1% of earth’s lower atmosphere)
• Water Vapor (H2O)
• Carbon Dioxide (CO2)
• Methane (CH4)
• Nitrous Oxide (N2O)
How does the greenhouse effect work?
1. Heat radiates into atm. from earth2. Causes molecules of gases to
vibrate3. Molecules release infrared
radiation (even longer wavelength)4. Radiation interacts w/ molecules 5. kinetic energy - warms lower atm.
& earth’s surface6. Overtime affects earth’s climate.
Without the greenhouse effect, earth would be frigid and uninhabitable
Global Climate Change
• AKA Global Warming • Caused by ENHANCED
Greenhouse Effect
CO2, NOX, CFCs, CH4
These gases absorb infrared (IR) radiation in upper atmosphere (stratosphere) and trap heat in lower atmosphere (troposophere) ABOVE “normal” levels, increasing greenhouse effect hence the name Greenhouse Gases
Global Climate Change Caused by
CO2 Concentration in atmosphere from: – Burning fossil fuels– Land conversion (loss of plant
material that absorb CO2)
• 2010: 389 ppm• 2050: 560 ppm• 2100: 1,390 ppm• 450 ppm as tipping point
other gases in atmosphere such as: –NOx, CFCs, CH4
Global Climate Change Caused by
Human Activities Emit Large Quantities of Greenhouse
Gases• Since Industrial Revolution – CO2, CH4, and N2O emissions higher
–Main sources: agriculture, deforestation, and burning of fossil fuels
• Correlation of rising CO2 and CH4 with rising global temperatures
Atmospheric Levels of CO2 and CH4, Global Temperatures, and Sea Levels
Fig. 19-4, p. 496
Correlation of CO2 and Temperature
Fig. 19-5, p. 497
Greenhouse Gases from Human Activities
Greenhouse Gas
Average Time in the Troposphere
Relative Warming Potential (CO2)
Carbon Dioxide 50-120 years 1
Methane 12-18 years 23
Nitrous Oxide 114-120 years 296
Chloroflorocarbons
11-20 years 900-8,300
Hydrochloro-flurocarbons
9-390 years 470-2,000
Hydroflurocarbons
15-390 years 130-12,700
Halons 65 years 5,500
Carbon Tetrachloride
42 years 1,400
Intergovernmental Panel on Climate Change (IPCC)
• Established 1988• Document past and project
future climate changes• Includes more than 2,500
scientists from more than 130 countries
IPCC Major Findingssee page 497
– 90–99% likely that lower atmosphere is warming• Especially since 1960• Mostly from human-caused increases in
greenhouse gases• Earth’s climate is now changing from
increased greenhouse gases
– Increased greenhouse gas concentrations will likely trigger significant climate disruption this century
– Ecological, economic, and social disruptions
Climate Change & Human Activities
• Increased Use of Fossil Fuels (CO2, CH4)
• Deforestation (CO2, N2O)
• Cultivation of Rice Patties (N2)
Global Warming = ENHANCED Greenhouse Effect–Melting icecaps & glaciers– Coral reef bleaching –Other
Global Warming Effects *
1. Melting ice caps & glaciers a. Evidence = retreating glaciers,
shrinking ice sheets
Global Warming Effects
2. Sea Level Rise a. FROM added
volumes of freshwater BUT also from thermal expansions
b. Coastline threats
(resulting in pop. displacement – LA, NYC, Miami)
Areas of Florida to Flood If Average Sea Level Rises by One
Meter
Fig. 19-11, p. 507
Global Warming Effects
3. Permafrost Decline in tundra regions (microclimate changes)
Global Warming Effects
3. Permafrost Decline in tundra regions (microclimate changes) –Methane, a greenhouse gas, will be
released into the atmosphere
• Arctic permafrost contains 50-60x the amount of carbon dioxide emitted annually from burning fossil fuels
• Methane in permafrost on Arctic Sea floor
Global Warming Effects4. In precipitation patterns
a. Frequent drought, rain, snow, flooding
b. Increased frequency and intensity of storms over warmed surfaces (Sandy/Katrina)
Global Warming Effects5. In biology
a. Migration patterns disruptedb. Food web disturbancesc. Habitat fragmentation (reduced
realized niche)
Global Warming Effects
6. Human Healtha. Health related
illnessesb. Disease spread by
organisms now with extended ranges (mosquitos & malaria)
Global Warming Effects
7. Agriculture a. Sea level rise will
impact farmland by flooding coastal regions
b. Severe Droughtc. Shift in farming
regions
Factors Contributing to Global Warming
Biggest Factor = CO2 Emissions
World’s Larges Emitters of CO2
Largest emitters, 20091. China2. United States3. European Union (27 countries)4. Indonesia5. Russia6. Japan7. India
World’s Larges Emitters of CO2
Factors Contributing to Global Warming
Waste Heat– Second Law of Thermodynamics!!– Burning Fossil Fuels = CO2 emissions + Waste
Heat
Factors Contributing to Global Warming
Solubility of CO2 in Ocean Water
Warmer oceans– Last century: 0.32-0.67C°increase– Absorb less CO2 and hasten
atmospheric warming– CO2 levels increasing acidity
– Affect phytoplankton and other organisms