anthropogenic sources of climate change
DESCRIPTION
Anthropogenic Sources of Climate Change. Major Anthropogenic Sources. CO 2 Aerosols Cement manufacturing Land use Ozone depletion Animal agriculture Deforestation. Fossil Fuel combustion and other human activities emit 30 Gigatons of CO 2 into the atmosphere annually - PowerPoint PPT PresentationTRANSCRIPT
Anthropogenic
Sources of
Climate Change
Major Anthropogenic Sources
• CO2
• Aerosols• Cement manufacturing• Land use• Ozone depletion• Animal agriculture• Deforestation
CO2 e
miss
ions
• Fossil Fuel combustion and other human activities emit 30 Gigatons of CO2 into the atmosphere annually
• Natural processes emit 770 Gigatons of CO2 into the atmosphere annually
• The 4% of CO2 emissions humans produce over a long period of time will inhibit Earth’s ability to radiate heat to the upper atmosphere
Indu
stria
l Re
volu
tion• Period from the 18th to the 19th
century where major changes in agriculture, manufacturing, mining, transportation, and technology had a profound effect on the socioeconomic and cultural conditions
• Introduction of steam power fuelled primarily by coal
Wikipedia | GNU
Indu
stria
l Rev
olut
ion
• Increased use of machinery powered by burning coal established dramatic increases in production capacity
• By 2005 global atmospheric concentrations of CO2 were 35% higher than they were before the Industrial Revolution
Wikipedia | Public Domain
What are
Aerosols? A colloid suspension of fine solid particles or liquid droplets in a gas Examples:
CloudsAir pollution (smog)
Reflect or absorb sunlight, which either cools or warms the atmosphere
In general, scientists believe aerosols have acted to combat climate change
Wikipedia | Public Domain
Key Groups of
Aerosols
Sulfates
Black Carbon
Mineral Dust
Organic Carbon
Nitrates
Sea Salt
Wikipedia | Public Domain
Wikipedia | Creative Commons
NASA
NASA
NASA
Wikipedia | Creative Commons
Sources of
Anthropogenic Aerosols
• Fossil fuel combustion
• Biomass burning• Automobiles• Incinerators• Smelters• Power plants
• Deforestation• Overgrazing• Dust • Cigarettes• Stoves• Fireplaces• Candles
FYI:10% of aerosols are
anthropogenic
• Produced in industrial areas • Eastern U.S. (New York, Pittsburgh)• Europe (Berlin, London)
• Anthropogenic emissions have increased in recent decades with increase in urbanization and industrialization in Asia
Sources of Anthropogenic Aerosols
Cem
ent
• Substance that sets and hardens independently & can bind other materials together• Crucial component in
buildings and roads• No viable recycling
potential
Cement Manufacturing
Calcium Carbonate is a key ingredient of cement
CaCO3 → CaO + CO2
Accounts for 5% of anthropogenic CO2 emissions
900 kg of CO2 is emitted for every 1000 kg of cement produced!!
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Land Use
NASA reports that “scientists estimate that between one-third and one-half of our planet's land surfaces have been transformed by human development”
A large body of research has documented the major role of land use and land cover change with variability in climate
Hum
an U
se o
f Lan
d
Urbanization Suburbanization
DeforestationIrrigating desert land
Damming riversResource extraction
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Pote
ntia
l Effe
cts
Thunderstorm frequency Change in water cycle
Change in energy budget
Active area of research …
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Ozone Cycle
Ozone prevents harmful
UV light from passing
through Earth’s
atmosphere
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Ozone
Depletion• Steady decline
of 4% per decade of stratospheric ozone
• Springtime decrease in stratospheric ozone over polar regions (ozone hole)
NASA accessed via Wikipedia
Two separate depletion events observed since late 1970’s
In both cases, ozone is destroyed by a reaction with halocarbon refrigerants (CFC’s, freons, and halons)
CFC’s = Chlorofluorocarbons
Image is a prediction of what
would happen if CFC’s were not
banned
NASA accessed via Wikipedia
Mont
real
Pr
otoc
ol
International treaty designed to phase out production of substances (CFC’s) believed to be responsible for ozone depletion
Signed in 1987 by 46 countries
If the protocol is followed, the ozone layer could recover by 2050
Notice any trends?
Animal Agriculture
(Globally) ruminant animals produce about 80 million metric tons of methane
This represents 28% of the anthropogenic methane emissions
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Defo
rest
atio
n
Removal of a forest where the land is converted to a non-forest use• Farms• Ranches• Urban use
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Defo
rest
atio
n
Plants use CO2 for photosynthesis
CO2 + H2O + energy from sun C6H12O6 + O2
Fewer plants leads to an increase in CO2 in the atmosphere
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Current Research Says…
Deforestation in the tropics accounts for nearly 20% of carbon emissions due to human activities
Maintaining forests as carbon sinks will make a significant contribution
to stabilizing atmospheric greenhouse gas concentrations