3/11/2015. Chapter 17. Video

Transcription

1 Chapter 17 Video 2 1

2 Weather the state of the atmosphere in one area at one time. What is the weather today here? Climate - the long term prevailing weather at a particular place What is the climate for here? Mark Twain said Climate is what we expect; weather is what we get Two places can have the same weather on the same day But they can have VERY different climates Weather: Seattle and Phoenix might both have rain today Climate : Seattle is wet and cool, Phoenix is dry and hot **It depends on their proximity top the equator. Layer of gases surrounding the planet Earth and retained by the Earth's gravity. It contains roughly 78% nitrogen, 21% oxygen, and 1% other. Its four layers differ in temperature, density and composition Human activity is changing the amounts of some gases Inactive gases 1% 2

3 Troposphere = bottommost layer Air for breathing, weather Stratosphere = km (7-31 mi) above sea level Drier and less dense, with little vertical mixing Colder in its lower regions Contains UV radiation-blocking ozone, The two highest levels of the atmosphere Mesosphere = km (31-56 mi) above sea level - Extremely low air pressure - Temperatures decrease with altitude Thermosphere = atmosphere s top layer - Extends upward to 500 m (300 mi) 3

4 Climate is determined by: Atmospheric Circulation Patterns Oceanic Circulation Patterns Local geography Solar activity Volcanic Activity Which is most important? Latitude (How far above/below you are from the equator) Video LATITUDE Latitude is the distance north or south of the equator. Measured in degrees. Equator is 0 degrees, the poles are 90 degrees Low Latitudes get the strongest, most concentrated sunlight. Night and Day are 12 hours, all year round High temps all year round High Latitudes sunlight is spread over a greater area, weaker, less energy Daylight hours vary At the poles the sun sets for only a few hours during the summer Dark almost all day during winter Average annual temperatures lower than at equator. 4

5 ATMOSPHERIC CIRCULATION Three basic rules: 1. Cold air sinks but pressure is stronger at lower levels so cold air gets compressed and thus warms. 2. Warm Air Rises lower pressure lets it expand and it cools down 3. Warm Air holds more water vapor than cold air so as it rises the water vapor cools and condenses How do we get wind? 1. Sun heats the earth surface. 2. Hot Air Rises 3.Cold Air replaces it wind! CORIOLIS EFFECT Coriolis effect = the north-south air currents of the convective cells appear to be deflected from a straight path Results in curving global wind patterns Hadley cells = near the equator, surface air warms, rises, and expands Releases moisture and heavy rainfall near the equator Ferrel cells and polar cells = lift air Creates precipitation at 60 degrees latitude north and south Causes air to descend at 30 degrees latitude 10 5

6 Prevailing winds winds that blow predominantly in one direction most of the year. From what direction does our prevailing wind come from? (They are deflected to the right in the Northern Hemisphere) Trade Winds the prevailing winds between 30 and equator. OCEAN CIRCULATION PATTERNS Water holds a lot of heat (think how much heat it takes to boil water!) Ocean currents are caused by winds and the movement of the earth The ocean currents move heat around the globe. In the summer where would you rather swim? Off California coast in LA or off the South Carolina coast Colder water flows south from Alaska, warm water flows north from the Caribbean Video 6

7 EL NINO VS LA NINA Some ocean currents change the way they flow: El Nino- Pacific Ocean water near Americas warms leads to increased clouds and rainfall in SW US La Nina Opposite of El Nino, cooler waters in Pacific near Americas, droughts in the SW US Pacific Decadal Oscillation Similar to El Nino but the switching occurs every years SUN S IMPACT Solar Cycle 11 year cycle of the sun. At the maximum the sun emits UV radiation This can warm the lower atmosphere and Earth. On earth the Northern Lights can be seen as far south as Mexico on occasion. Increased radiation from the sun can cause warming of the atmosphere Seasons Why do we have them? All due to the tilt of the earth 23.5 relative to the plane of its orbit. (Angle of the sun s rays striking the Earth) zchangesun_qt%20big%20progre.mov 7

8 Temperature Inversion: Air circulation usually stops pollution from accumulating to dangerous levels. Inversions trap pollution near the Earth s Surface Temperature usually decreases with altitude But a warm layer above a cold layer will trap pollution (Hot air rises, right? Hot smoke rises, but if atmosphere is just as warm, the smoke stays put) Temperature Inversion: Video 8

9 Air Pollution Harmful substances built up in the air to an unhealthy level Pollutants can be from human activity industry soot Pollutants can be natural volcanic ash, pollen, dust, spores Primary Pollutant put into air directly by human activity Soot from smoke and fires 9

10 Secondary Pollutant form when primary pollutants react with each other or natural substances Ground Level Ozone is formed when car emissions (primary) interact with oxygen and UV rays (both natural) Major factors are H 2 O and Sunlight AKA: Tropospheric Ozone 10

11 Clean Air Act Federal law that regulates air emissions. This law authorizes EPA to establish National Ambient Air Quality Standards (NAAQS) to protect public health and the environment. The setting of maximum pollutant standards was coupled with directing the states to develop state implementation plans (SIP's) applicable to appropriate industrial sources in the state. Overseen by Environmental Protection Agency (EPA) The EPA required the gradual elimination of lead in gasoline. To date lead pollution has been reduced by more than 90 % in US. California Zero Emission Law Is that possible? Battery operated vehicles are the only true ZEVs (zero emission vehicles) Major Air Pollutants Pollutant Composition Source P/S Effects Particulate matter Nitrogen oxides Sulfur oxides Carbon oxides Various Industry P Respiratory illness NO 2 SO 2 CO, CO 2 Cars, industry, fertilizer Coal-fire power plants Cars, industry P P P Irritate respiratory Irritate respiratory Reduces blood s ability to carry O 2 ozone O 3 Photochemical S Irritate eyes, respiratory 11

12 Industrial plants burn fossil fuels Burning releases Sulfur Dioxide and Nitrous Oxide Power Plants emit 2/3 of ALL SO2 and 1/3 of ALL NO VOCs (Volatile Organic Compounds) - chemical compounds that form toxic fumes Given off by Oil refineries, Dry Cleaners, Chemical plants Clean Air Act Requires Industries to use: Scrubber: cleans emissions of plants by washing it and filtering it Electrostatic Precipitator: uses static charges to get particulates to clump together and collect, clean gas continues on. (used in cement factories/coal burning plants) 12

13 25 Industrial Air Pollution Plant Scherer Georgia 13

14 Smog: Air pollution that hangs over urban areas and reduces visibility Industrial (gray air) smog = industries burn coal or oil Photochemical (brown air) smog Secondary Pollution Produced by a series of reactions - Hot, sunny cities surrounded by mountains - Light-driven reactions of primary pollutants and normal atmospheric compounds - Morning traffic exhaust releases pollutants - Irritates eyes, noses, and throats - Vehicle inspection programs in the U.S. have decreased smog Nitrogen Oxide is associated with Photochemical Smog Copyright 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings 14

15 Sulfur dioxides (SO 2 ) Industrial smog Nitrogen Oxide (NO) Photochemical smog Copyright 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings OZONE LAYER Ozone is the chemical compound O 3 Large concentration is found in the stratosphere Ozone Layer absorbs most UV radiation coming from the sun UV radiation can damage organisms cells UV-B- most absorbed by ozone Chemicals Can Destroy Ozone CFCs chlorofluorocarbons CFCs are non flammable, non poisonous, and non reactive at the Earth s surface CFCs used as propellants in spray cans and coolants in fridges/air conditioners It takes years for CFCs to reach the stratosphere from the Earth's surface 15

16 CFCs are broken apart in the stratosphere High energy of the UV radiation breaks it down The single chlorine from CFC can react with O 3 and changes it, depleting the O 3 Scientists estimate that a single chlorine atom can break down 100,000 ozone molecules. OZONE HOLE First noticed in 1970 from satellite photos over the South Pole What Causes it? During the cold polar winters, dry stratospheric air over the pole is isolated. Air becomes so cold that it condenses and forms clouds (Polar Stratospheric clouds: high-altitude clouds made of water and nitric acid at - 80 C) Chlorine from CFCs builds up on the surface of the clouds When the pole begins to warm the chlorine goes back to depleting ozone. VIDEO ON OZONE DEPLETION 16

17 WHY CARE ABOUT OZONE? Ever have a bad sunburn? UV radiation can damage organisms DNA Can lead to skin and other cancers Notable impact to amphibian eggs (death/mutations) Phytoplankton can be killed by UV Phytoplankton is the producer for most ocean food chains Phytoplankton loss would also effect atmospheric CO 2 levels Montreal Protocol Many nations banned the use of CFCs in 1992 (US stopped production by 2000) CFCs still a problem.why? CFCs molecules remain in the stratosphere for years Many air pollution effects are short term Can be reversed when exposure is decreased Short term effects: Nausea Headaches Eye Irritations Coughing Upper respiratory infections (bronchitis, pneumonia) Will make asthma worse Greatest effect on children ages 5 and lower 17

18 Many air pollution effects are long term Cannot be reversed when exposure is decreased Long term effects: Emphysema Lung Cancer Heart Disease May damage lungs of young children Air inside a building is sometimes WORSE than air outside Chemicals used in making carpets, furniture, paints can pollute indoor air Sick Building Syndrome buildings with very poor air quality Found in hot climates where buildings are sealed to keep out heat. Fungi can grow and there is no release of the toxic chemicals released from carpet, paint etc. All builds up to drastically reduce indoor air quality 18

19 Preventing bad indoor air pollution Remove the source of the pollution Remove carpet, new paint Good ventilation to mix the indoor air with outdoor air Decreases the amount of pollution per unit of air Radon Gas Colorless, odorless gas 2 nd leading cause of lung cancer Occurs after uranium decays, found naturally in the earth, can seep into houses. Have a radon detector in the house 19

20 Asbestos A fire resistant substance used in building materials before the 1970s. When inhaled the fibers can cut and scar the lungs leading to breathing difficulties and heart failure. Billions of dollars have been spent in asbestos removal Defined as unwanted sound Noise kills nerve cells in the ear 12% of teens have permanent hearing loss Intensity of sound is measured in decibels 120 db is at the threshold of pain. Noise levels greater than this can cause permanent damage. Protection from noise pollution: Mufflers on autos and yard equipment MP3 players in Europe can only go up to 100 db Ear protection 20

21 Not a direct hazard to human health Does impact environment and enjoyment of night sky. Bigger threat is wasted energy Upward directed light is wasted, only goes to space Acid precipitation is rain with a high concentration of acids ph measures acid concentration Low numbers are more acidic. Below 7 is acidic. The closer to zero the more acidic. Each change in ph (1 to 2) indicates a ten times difference in acidity Normal rain has a ph of 5.6, acid precipitation starts at

22 Acidification Increase of acid in soils or lakes Acid chemically reacts with soil minerals Some nutrients are dissolved and washed away from where plants can use them Metals like aluminum are released into the soil and possibly absorbed High enough levels of these metals can be toxic How Does Acid Precipitation Affect Soils and Plants 22

23 Aquatic animals live within a very narrow ph range Acid rain changes ph level of lake and kills fish Acid precipitation leaches metals like aluminum from soil near lake/river Metals accumulate in fish bodies until reach toxic levels Acid Shock In the spring when acid snow melt and flows into rivers and lakes the sharp change in ph kills massive amounts of aquatic creatures 46 23

24 Kills fish and other aquatic organisms. Acid shock in the spring may kill many at one time. Humans depend on plants, animals, and seafood items for food If plants, animals, fish die off we lose food sources. Toxic metals taken in by plants, animals, fish also accumulate in us and can reach toxic levels Aesthetics Statues and buildings are deteriorating due to acid rain 24

25 Acid rain may dissolve the calcium carbonate found in concrete, marble, and limestone. Acid rain is hard to regulate because the pollution that causes it blows with the wind. One country s pollution could float into another country causing acid rain there. Countries are signing Air Quality agreements with each other to help reduce polluting emissions 25

26 What is climate change? Global climate change = describes trends and variations in Earth s climate - Temperature, precipitation, storm frequency Global warming = an increase in Earth s average temperature - Earth s climate has varied naturally through time - The rapid climatic changes taking place now are due to human activity: fossil fuels, combustion, and deforestation Copyright 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings 26

27 GREENHOUSE EFFECT The earth is like a greenhouse The atmosphere acts like the glass which lets the sun s rays pass through. The earth absorbs this as heat energy and keeps it in, only letting a little heat out The gases in the atmosphere absorb the radiation keeping it from escaping out to space This absorption of radiation by gases is called the greenhouse effect GREENHOUSE GASES Water Vapor, CO 2, CFCs, Methane and NO x all absorb radiation Water vapor and CO 2 are the primary greenhouse gases Since 1958 (in Hawaii) CO 2 levels have been measured reflective of the entire earth (the gases have traveled across the entire Pacific Ocean) Levels are higher in the winter: fewer leaves on the trees (dying grasses and leaves release carbon) General increase because of burning fossil fuels(not just in winter) 27

28 GLOBAL WARMING Where does all the CO 2 come from? Power plants and cars that burn fossil fuels and deforestation Why be concerned? CO 2 is a greenhouse gas Scientists believe the increase will warm earth more than normal Direct correlation between CO 2 levels and global warming Aerosols may exert a cooling effect Aerosols = microscopic droplets and particles that have either a warming or cooling effect Soot, or black carbon aerosols, cause warming by absorbing solar energy - But, most tropospheric aerosols cool the atmosphere by reflecting the Sun s rays Sulfate aerosols produced by fossil fuel combustion may slow global warming, at least in the short term - Volcanic eruptions reduce sunlight reaching the earth and cool the Earth Copyright 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings 28

29 Copyright 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Albedo Effect Ability of a surface to reflect light Ice, especially with snow on top of it, has a high albedo Most sunlight hitting the surface bounces back towards space Copyright 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings 29

30 WHAT HAPPENS IF THE EARTH WARMS? Melting Ice and Rising Sea Levels Coastal areas flooded Nearly 3 billion people live within 100 km of a coast Excess sea water can change freshwater aquifers near coasts Changing Weather Patterns Warming the oceans could change currents that influence weather today Human Health Problems Deaths due to heat waves Longer growing seasons, more pollen, more asthma Warmer weather allow mosquitoes and other disease carrying organisms to live longer Agriculture Heat leads to droughts, severe impact to crops May change where plants and animals live Kyoto Protocol Nations met and laid out timelines for reducing CO 2 emissions Decrease emissions by 5% from 1990 levels by Reducing CO 2 is difficult for developing countries Need industry using cheap fossil fuel to improve economies 30

31 Results from three simulations Figure (a) shows natural climate factors only - Volcanoes Figure (b) shows only human factors - Emissions of greenhouse gases Figure (c) shows both factors Copyright 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Current and future trends and impacts Evidence that climate conditions have changed since industrialization has increased Intergovernmental Panel on Climate Change (IPCC) - An international panel of scientists and government officials established in Has presented a series of reports on the synthesis of scientific information concerning climate change Copyright 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings 31

32 Temperature increases will continue The IPCC report concludes that average surface temperatures on earth have been rising since 1906, with most of the increase occurring in the last few decades Copyright 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings U.S. Global Change Research Program (1990) Predicted: - Temperature increases - Worse droughts and flooding - Decreased crop yields and water shortages - Health problems and mortality - Altered forest ecosystems - Lost coastal areas - Undermined Alaskan buildings and roads Copyright 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings 32

33 The debate over climate change is over Most Americans accept that fossil fuel consumption is changing the planet An Inconvenient Truth helped turn the tide - 84% of people surveyed thought that humans contribute to global warming - Many corporations offer support for greenhouse gas reductions Inconvenient Truth Video Copyright 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Electricity generation A coal-fired, electricitygenerating power plant Largest source of U.S. CO 2 emissions Two ways to reduce fossil fuel use: conservation and efficiency - Arise from technology and individual choices - Replacing worn-down appliances with newer models, lifestyle choices - Use fewer greenhouse-gas-producing products Copyright 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings 33

34 Sources of electricity We can change the energy we use - Natural gas - Carbon-capture = technologies or approaches that remove CO 2 from power plant emissions - Carbon sequestration (storage) = storing carbon somewhere (underground?) where it will not seep out - Use technologies and energy sources without using fossil fuels (nuclear, hydroelectric, solar power, etc.) Copyright 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Transportation 2nd largest U.S. greenhouse gas The typical automobile is highly inefficient Ways to help: - Technology: make vehicles more fuel-efficient, hybrid cars - Drive less and use public transportation - Public transportation is the most effective way to conserve energy, reduce pollution - Live nearer your workplace, so you can bike or walk Copyright 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings 34

35 Conventional cars are inefficient Copyright 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings You can reduce your own footprint Our carbon footprint expresses the amount of carbon we are responsible for emitting - You may apply many strategies such as deciding where to live, how to get to work, and what appliances to buy to decrease your footprint Global climate change may be the biggest challenge facing us and our children - Taking immediate action is the most important thing we can do Copyright 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings 35

36 Reviews (APES in a box) Ozone depletion Climate Change Copyright 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings 36