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Getty Images Greenhouse Gases. Percent Major Atmosphere Gases Nitrogen78.1 Nitrogen78.1 Oxygen20.9 Oxygen20.9 Argon.93 Argon.93 Water Vapor (H 2 0), Carbon.

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Presentation on theme: "Getty Images Greenhouse Gases. Percent Major Atmosphere Gases Nitrogen78.1 Nitrogen78.1 Oxygen20.9 Oxygen20.9 Argon.93 Argon.93 Water Vapor (H 2 0), Carbon."— Presentation transcript:

1 Getty Images Greenhouse Gases

2 Percent Major Atmosphere Gases Nitrogen78.1 Nitrogen78.1 Oxygen20.9 Oxygen20.9 Argon.93 Argon.93 Water Vapor (H 2 0), Carbon Dioxide (CO 2 ), Methane (CH 4 ), Nitric Oxide (N 2 O), Ozone (O 3 ) <1 Water Vapor (H 2 0), Carbon Dioxide (CO 2 ), Methane (CH 4 ), Nitric Oxide (N 2 O), Ozone (O 3 ) <1

3 What are Greenhouse Gases Allow sunlight to enter atmosphere freely Allow sunlight to enter atmosphere freely mostly in visible light wavelengths mostly in visible light wavelengths Sunlight hits surface and reradiated to space Sunlight hits surface and reradiated to space As longer wavelengths of infrared radiation As longer wavelengths of infrared radiation Greenhouse gases absorb reradiated infrared radiation Greenhouse gases absorb reradiated infrared radiation Heat is trapped by gases Heat is trapped by gases

4 Major Greenhouse Gases Water Vapor55-70 Water Vapor55-70 CO 2 25 CO 2 25 CFCs11 CFCs11 CH 4 5 CH 4 5 N 2 O2 N 2 O2 O 3 <1 O 3 <1

5 How Does Greenhouse Work Glass transparent to most wavelengths of solar radiation Glass transparent to most wavelengths of solar radiation Glass opaque to longer (thermal infrared) wavelengths Glass opaque to longer (thermal infrared) wavelengths Soil, plants, are heated Soil, plants, are heated Radiate heat to warm air Radiate heat to warm air Close car in summer works the same Close car in summer works the same Greenhouse really works differently Greenhouse really works differently Soil, plants heated Soil, plants heated Air then heated Air then heated Air rise, cooler air replaces heated air Air rise, cooler air replaces heated air

6 These two simple cartoons show the multiple paths sunlight takes as it enters Earth's atmosphere (left) and the basic mechanism of the greenhouse effect (right). The portion of incoming sunlight that is absorbed by Earth is re-emitted as infrared radiation. Some IR energy escapes directly to space, but most is absorbed by greenhouse gases in the atmosphere. This warms Earth's atmosphere. Credit: The COMET Program

7 Are Greenhouse Gases Bad No, not in excessive amounts Gases needed to heat atmosphere If not greenhouse gases, atmosphere would be 54oF colder If too many gases, atmosphere heats up too much

8 Various wavelengths of solar EM radiation penetrate Earth's atmosphere to various depths. Fortunately for us, all of the high energy X-rays and most UV is filtered out long before it reaches the ground. Much of the infrared radiation is also absorbed by our atmosphere far above our heads. Most radio waves do make it to the ground, along with a narrow "window" of IR, UV, and visible light frequencies. Image courtesy STCI/JHU/NASA.

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10 Household Greenhouse Contributions Private car -- greatest contribution Private car -- greatest contribution

11 A kilogram of carbon dioxide will fill a large family fridge. A ton of carbon dioxide will fill a family home. A kilogram of carbon dioxide will fill a large family fridge. A ton of carbon dioxide will fill a family home.

12 Major Gases Carbon Dioxide (CO2) is most Chlorofluorocarbon (CFCs) Methane (CO) Ozone (O 3 ) Nitrous oxide (NO 2 ) Water vapor not included

13 Carbon Cycle Carbon moves from the atmosphere to plants. Carbon moves from the atmosphere to plants. In the atmosphere, carbon is attached to oxygen to form carbon dioxide (CO2). With the help of the Sun, through the process of photosynthesis, carbon dioxide is pulled from the air to make plant food from carbon. In the atmosphere, carbon is attached to oxygen to form carbon dioxide (CO2). With the help of the Sun, through the process of photosynthesis, carbon dioxide is pulled from the air to make plant food from carbon. Carbon moves from plants to animals. Carbon moves from plants to animals. Through food chains, the carbon that is in plants moves to the animals that eat them. Animals that eat other animals get the carbon from their food too. Through food chains, the carbon that is in plants moves to the animals that eat them. Animals that eat other animals get the carbon from their food too. Carbon moves from plants and animals to the ground. Carbon moves from plants and animals to the ground. When plants and animals die, their bodies, wood and leaves decay bringing the carbon into the ground. Some becomes buried miles underground and will become fossil fuels in millions and millions of years. When plants and animals die, their bodies, wood and leaves decay bringing the carbon into the ground. Some becomes buried miles underground and will become fossil fuels in millions and millions of years. Carbon moves from living things to the atmosphere. Carbon moves from living things to the atmosphere. Each time you exhale, you are releasing carbon dioxide gas (CO2) into the atmosphere. Animals and plants get rid of carbon dioxide gas through a process called respiration. Each time you exhale, you are releasing carbon dioxide gas (CO2) into the atmosphere. Animals and plants get rid of carbon dioxide gas through a process called respiration. Carbon moves from fossil fuels to the atmosphere when fuels are burned. Carbon moves from fossil fuels to the atmosphere when fuels are burned. When humans burn fossil fuels to power factories, power plants, cars and trucks, most of the carbon quickly enters the atmosphere as carbon dioxide gas. Each year, five and a half billion tons of carbon is released by burning fossil fuels. Thats the weight of 100 million adult African elephants! Of the huge amount of carbon that is released from fuels, 3.3 billion tons enters the atmosphere and most of the rest becomes dissolved in When humans burn fossil fuels to power factories, power plants, cars and trucks, most of the carbon quickly enters the atmosphere as carbon dioxide gas. Each year, five and a half billion tons of carbon is released by burning fossil fuels. Thats the weight of 100 million adult African elephants! Of the huge amount of carbon that is released from fuels, 3.3 billion tons enters the atmosphere and most of the rest becomes dissolved in

14 The Carbon Cycle More Carbon going to atmosphere than is used Therefore more greenhouse gas in atmosphere Earth warms

15 Methane Concentration is far less than that of CO 2 Concentration is far less than that of CO 2 Methane is 21 times as potent a greenhouse gas Methane is 21 times as potent a greenhouse gas May now be responsible for ~20% of the predicted global warming May now be responsible for ~20% of the predicted global warming

16 Methane Source Non-biogenic & biogenic sources Non-biogenic & biogenic sources Non-biogenic Non-biogenic emissions from fossil fuel mining and burning (natural gas, petroleum and coal), biomass burning, waste treatment and geological sources emissions from fossil fuel mining and burning (natural gas, petroleum and coal), biomass burning, waste treatment and geological sources (fossil CH4 from natural gas seepage in sedimentary basins and (fossil CH4 from natural gas seepage in sedimentary basins and geothermal/volcanic CH4) geothermal/volcanic CH4) Biogenic Sources Biogenic Sources 70% of the global total 70% of the global total wetlands, rice agriculture, livestock, landfills, forests, oceans and termites wetlands, rice agriculture, livestock, landfills, forests, oceans and termites Anthropogenic Anthropogenic rice agriculture, livestock, landfills and waste treatment, some biomass burning, and fossil fuel combustion rice agriculture, livestock, landfills and waste treatment, some biomass burning, and fossil fuel combustion Agricultureflood rice production, livestock most abundant Agricultureflood rice production, livestock most abundant Non-Anthropogenic (Natural) Non-Anthropogenic (Natural) wetlands, oceans, forests, fire, termites and geological sources wetlands, oceans, forests, fire, termites and geological sources

17 Summary of Sources Methane ( marsh gas) released by: Methane ( marsh gas) released by: Natural processes Natural processes Decay in swamps Decay in swamps Human activities Human activities mining, processing, and use of coal, oil, and natural gas; mining, processing, and use of coal, oil, and natural gas; growing rice in paddies; growing rice in paddies; burning forests; burning forests; raising cattle (fermentation in their rumens produces methane that is expelled from their GI tract) raising cattle (fermentation in their rumens produces methane that is expelled from their GI tract)

18 Ozone Sources Ozone molecule consists of 3 oxygen atoms Ozone molecule consists of 3 oxygen atoms Good when up high in atmosphere Good when up high in atmosphere Blocks ultraviolet radiation Blocks ultraviolet radiation Bad when lower Bad when lower Irritates respiratory system Irritates respiratory system Harms vegetation an crops Harms vegetation an crops A major component of smog A major component of smog Formed through conversion of nitrogen oxides and volatile organic compounds through heat and sunlight Formed through conversion of nitrogen oxides and volatile organic compounds through heat and sunlight Industry, utilities, and vehicle exhaust contribute most nitrogen oxide. Industry, utilities, and vehicle exhaust contribute most nitrogen oxide. Plants emit VOC and soil emits NO Plants emit VOC and soil emits NO Formed only during the day Formed only during the day

19 Ozone Hole From CFCs From CFCs Some natural depletion from volcanoes, sun Some natural depletion from volcanoes, sun Allows more uv light Allows more uv light Ultraviolet rays can cause skin cancer, cataracts, and may depress the immune system Ultraviolet rays can cause skin cancer, cataracts, and may depress the immune system

20 Source of Nitrogen Dioxide Reddish brown gas Very reactive produced by motor vehicles (55%), power plants (22%), and other industrial, commercial, agricultural, and residential sources that burn fuels or biomass (22%) Lightning and microbial activity also form nitrogen oxide Mixes with water to form acid rain Can also form particles and aerosols EPA

21 Nitrogen Oxide Continued Reacts with sunlight to form ozone Reacts with sunlight to form ozone Is a nutrient in water Is a nutrient in water Leads to over- productivity, death in ocean, low oxygen Leads to over- productivity, death in ocean, low oxygen

22 Chlorofluorocarbons (CFCs) Synthetic gases in which the hydrogen atoms of methane replaced by atoms of fluorine and chlorine (e.g., CHF2Cl, CFCl3, CF2Cl2). Synthetic gases in which the hydrogen atoms of methane replaced by atoms of fluorine and chlorine (e.g., CHF2Cl, CFCl3, CF2Cl2). Gases are noninflammable, nontoxic, and very stable Gases are noninflammable, nontoxic, and very stable Used in industry as: Used in industry as: refrigerants (e.g., in refrigerators and air conditioners) refrigerants (e.g., in refrigerators and air conditioners) solvents solvents propellants in aerosol cans (now banned in some countries) propellants in aerosol cans (now banned in some countries) in the manufacture of plastic foams in the manufacture of plastic foams

23 CFCs Continued Non-reactive Non-reactive Remain in atmosphere for yrs to decompose Remain in atmosphere for yrs to decompose Pose threat to ozone layer Pose threat to ozone layer

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25 Carbon Dioxide IPCC Report Atmospheric CO2 concentration has increased from pre-industrial value of about 280 ppm to 379 ppm in 2005 Atmospheric CO2 concentration increased by only 20 ppm over 8000 years prior to industrialization Since 1750, CO2 concentration has risen by nearly 100 ppm Annual CO2 growth rate larger during last 10 years (1995–2005 average: 1.9 ppm yr–1) than since continuous direct measurements began (1960–2005 average: 1.4 ppm yr–1).

26 Classic CO2 Graph Carbon Dioxide has steadily increased anthropogenic cause Carbon Dioxide has steadily increased anthropogenic cause Probably began in industrial revolution Probably began in industrial revolution Superimposed are variations with seasons Superimposed are variations with seasons More CO2 in winter, less in winter More CO2 in winter, less in winter Due to photosynthesis Due to photosynthesis

27 Globally Go Forth and Multiply! World Population CO2 World Population vs. CO2

28 The concentrations and radiative forcing by (a) carbon dioxide (CO2), (b) methane (CH4), (c) nitrous oxide (N2O) and (d) the rate of change in their combined radiative forcing over the last 20,000 years reconstructed from Antarctic and Greenland ice and fi rn data (symbols) and direct atmospheric measurements (panels a,b,c, red lines). The grey bars show the reconstructed ranges of natural variability for the past 650,000 years (IPCC)

29 Carbon Dioxide Sources Carbon in nonliving environment as: Carbon in nonliving environment as: carbon dioxide (CO2) in atmosphere and dissolved in water carbon dioxide (CO2) in atmosphere and dissolved in water Carbonate rocks (limestone and coral = CaCO3) Carbonate rocks (limestone and coral = CaCO3) Deposits of coal, petroleum, and natural gas derived from once-living things Deposits of coal, petroleum, and natural gas derived from once-living things Dead organic matter, e.g., humus in the soil Dead organic matter, e.g., humus in the soil

30 Carbon Intake & Release Used by plants Used by plants Photosynthesis Photosynthesis Convert carbon dioxide to organic matter Convert carbon dioxide to organic matter Carbon returns to the atmosphere and water by Carbon returns to the atmosphere and water by respiration (as CO2) respiration (as CO2) burning burning decay (producing CO2 if oxygen is present, methane (CH4) if it is not. decay (producing CO2 if oxygen is present, methane (CH4) if it is not.

31 Anthropogenic Causes Burning fossil fuels (coal, oil, natural gas) Burning fossil fuels (coal, oil, natural gas) Carbon returns to atmosphere that has been locked within earth for millions of years. Carbon returns to atmosphere that has been locked within earth for millions of years. Land use change. Clearing and burning of forests, especially in the tropics. Recently, large areas of the Amazon rain forest have been cleared for agriculture and cattle grazing. Land use change. Clearing and burning of forests, especially in the tropics. Recently, large areas of the Amazon rain forest have been cleared for agriculture and cattle grazing. Burning vegetation increases CO2 Burning vegetation increases CO2 Cutting trees decrease use of CO2 during photosynthesis, more in atmosphere Cutting trees decrease use of CO2 during photosynthesis, more in atmosphere Since 1750, about 2/3rds of anthropogenic CO2 emissions from fossil fuel burning and about 1/3rd from land use change htmlhttp://www.ncdc.noaa.gov/paleo/ctl/landuse. html - Landuse animation

32 Clearing of the Amazon Rainforest Without people, a yearly fire season in the Amazon Rainforest would be almost as unlikely as a hurricane season in Antarctica. Today, however, the Amazon is a frontier, and settlers are burning hundreds of thousands of acres of rainforest each year for cattle pasture and farms. Accidental fires degrade thousands of acres more.


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