Anthropogenic Sources of Climate Change

Major Anthropogenic Sources CO 2 CO 2 Aerosols Aerosols Cement manufacturing Cement manufacturing Land use Land use Ozone depletion Ozone depletion Animal agriculture Animal agriculture Deforestation Deforestation

CO 2 emissions Fossil Fuel combustion and other human activities emit 30 Gigatons of CO 2 into the atmosphere annually Fossil Fuel combustion and other human activities emit 30 Gigatons of CO 2 into the atmosphere annually Natural processes emit 770 Gigatons of CO 2 into the atmosphere annually Natural processes emit 770 Gigatons of CO 2 into the atmosphere annually The 4% of CO 2 emissions humans produce over a long period of time will inhibit Earth’s ability to radiate heat to the upper atmosphere The 4% of CO 2 emissions humans produce over a long period of time will inhibit Earth’s ability to radiate heat to the upper atmosphere

Industrial Revolution 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

Industrial Revolution Increased use of machinery powered by burning coal established dramatic increases in production capacity By 2005 global atmospheric concentrations of CO 2 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:Clouds Air 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 Key Groups of Aerosols Sulfates Sulfates Black Carbon Black Carbon Mineral Dust Mineral Dust Organic Carbon Nitrates Nitrates Sea Salt Wikipedia | Public Domain Wikipedia | Creative Commons 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 Produced in industrial areas Eastern U.S. (New York, Pittsburgh) Eastern U.S. (New York, Pittsburgh) Europe (Berlin, London) Europe (Berlin, London) Anthropogenic emissions have increased in recent decades with increase in urbanization and industrialization in Asia Anthropogenic emissions have increased in recent decades with increase in urbanization and industrialization in Asia Sources of Anthropogenic Aerosols

Cement Substance that sets and hardens independently & can bind other materials together Substance that sets and hardens independently & can bind other materials together Crucial component in buildings and roads Crucial component in buildings and roads No viable recycling potential No viable recycling potential

Cement Manufacturing Calcium Carbonate is a key ingredient of cement CaCO 3 → CaO + CO 2 Accounts for 5% of anthropogenic CO 2 emissions 900 kg of CO 2 is emitted for every 1000 kg of cement produced!! Wikipedia | Creative Commons

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

Human Use of Land Urbanization SuburbanizationDeforestation Irrigating desert land Damming rivers Resource extraction Wikipedia | GNU

Potential Effects Thunderstorm frequency Change in water cycle Change in energy budget Active area of research … Wikipedia | Creative Commons

Ozone Cycle Ozone prevents harmful UV light from passing through Earth’s atmosphere Wikipedia | Public Domain

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

Montreal Protocol 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

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Animal Agriculture (Globally) ruminant animals produce about 80 million metric tons of methane This represents 28% of the anthropogenic methane emissions Wikipedia | Public Domain

Deforestation Removal of a forest where the land is converted to a non-forest use Farms Farms Ranches Ranches Urban use Urban use Wikipedia | Public DomainWikipedia | GNU

Deforestation Plants use CO 2 for photosynthesis CO 2 + H 2 O + energy from sun  C 6 H 12 O 6 + O 2 Fewer plants leads to an increase in CO 2 in the atmosphere Wikipedia | Creative Commons

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