Presentation on theme: "Atmosphere and Climate Change ch.13 Why You Should Care: Popular Issue – interesting Affects federal policy, global policy Academic Study It is a reality."— Presentation transcript:
Atmosphere and Climate Change ch.13 Why You Should Care: Popular Issue – interesting Affects federal policy, global policy Academic Study It is a reality Can we do something about it?
Global Temperatures are Increasing http://data.giss.nasa.gov/gistemp/graphs_v3/Fig.A 2.gif
Carbon Dioxide Has Increased http://www.esrl.noaa.gov/gmd/ccgg/trends/
Global Temperature Change Over Time http://www.scotese.com/climate.htm
What is the difference between weather and climate? Weather – is the state of the atmosphere at a particular place at a particular time Climate – is the long-term prevailing weather conditions at a particular place based on records taken
What Factors Determine the Climate? Latitude Atmospheric circulation patterns Oceanic patterns Local geography Solar activity Volcanic activity
1. Latitude- the distance from the equator in degrees north or south. The amount of solar energy an area of Earth receives depends on its latitude http://www2.gi.alaska.edu/alison/SNW_09B_Sola rEnergy.html
2. Atmospheric Circulation Cold Air sinks because it is denser. As it sinks it compresses and warms. Warm air rises. It expands and cools as it rises. Warm air can hold more water vapor than cold air can. Solar energy heats the ground warm air rises cooler air moves in to replace it This circulation pattern determines Earths precipitation pattern
Atmospheric circulation driven by uneven heating of the Earth by the Sun http://earthguide.ucsd.edu/eoc/middle_school_t/teachers/earth/sp_atmosphere/p_atmo_circulation_explanation.html
Atmospheric Circulation, contd Prevailing winds – blow predominantly in one direction, not directly northward or southward (because of Earths rotation) Trade winds – blow b/w 30* North and 30* South Westerlies – produced b/w 30*-60* North and South latitudes Polar Easterlies – blow b/w 60* to poles both North and South
3. Oceanic Circulation The ocean currents redistribute heat on the planet. The Gulf Stream carries warm tropical waters to the polar regions California current carries cooler polar waters towards the tropics
Surface Currents that change El Nino – Southern Oscillation. 6-18 months. Winds in the western Pacific, which are usually weak, strengthen and push warm water eastward. Effects: 1. Increased rainfall west coast of S. America and S. eastern U.S. 2. Drought in Indonesia and Australia 3. http://www.esrl.noaa.gov/psd/map/clim/sst_olr/el_nino_an im.shtml http://www.esrl.noaa.gov/psd/map/clim/sst_olr/el_nino_an im.shtml La Nina – water in the eastern Pacific is cooler than usual. Pacific Decadal Oscillation – 20-30 yr. change in location of warm and cold water masses in the Pacific Ocean
4. Topography Temperatures fall by 11* F for every 1,000 m. increase in altitude Rain shadow - Rain on West side of Mountain – dry on East. Water cools and warms faster than land http://www.newton.dep.anl.gov/askasci/env99/env99395. htm http://www.newton.dep.anl.gov/askasci/env99/env99395. htm
Other Influences on Earths Climate Solar maximum – the sun emits an increased amount of UV radiation which warms the ozone more hence warming the stratosphere. Volcanic Eruptions – Sulfur dioxide gas reacts with the smaller amounts of water vapor and dust in the stratosphere forming a bright layer of haze than reflects enough sunlight to cause global temps. to decrease Aerosols – cool the atmosphere
Seasonal Changes in Climate Seasons are a result of the 23.5* tilt in Earths axis. Because of the tilt, the suns rays hit the Earth at different angles thus heating it unevenly. During summer in the N. Hemisphere, the N. Hemisphere tilts toward the sun and receives direct sunlight
POP QUIZ SEC. 1 answer on ¼ sheet of paper and turn in 1. List one reason you should care about climate change. 2. What is the difference between weather and climate? #3-5 List 3 factors that determine the climate
Sec. 2 The Ozone Shield Ozone – O 3 The ozone layer is in the stratosphere and absorbs harmful UV rays from the sun. CFCs – chloroflourocarbons – coolant in refridgerators and air conditioners, and propellent in spray cans. CFCs break apart in the stratosphere and destroy ozone A single chlorine atom from CFC can destroy 100,000 ozone molecules
Ozone Hole – a thinning of the ozone layer that occurs over the poles during the spring. http://www.atmos.pku.edu.cn/yhu/ozone.html
Ozone Formation http://www.theozonehole.com/twenty.htm Effects of ozone thinning on humans: UV damages DNA can cause skin cancer Effects of ozone thinning on plants and animals: kills phytoplankton – provides most of the oxygen on earth Harms amphibian eggs – amphibians are indicators of healthy/unhealthy ecosystem Interferes with photosynthesis of plants
Protecting the Ozone Layer 1987 Montreal Protocol – nations agreed to put limit on CFC emissions 1992 – developed countries agreed to eliminate all CFCs by 1995 CFCs remain active in stratosphere for 60-120 years
Sec.3 Global Warming an increase in the earth's average atmospheric temperature that causes corresponding changes in climate and that may result from the greenhouse effect. Exacerbated by the greenhouse effect- the radiation of heat given by trapped gases in the atmosphere. Major greenhouse gases: water vapor, carbon dioxide, chlorofluorocarbons, methane, and nitrous oxide.
Measuring Carbon Dioxide in the atmosphere Measured at Mauna Loa, Hawaii Most CO 2 released is 1) dissolved in the ocean 2) absorbed by plants CO 2 increases acidity in oceans – it combines with water to make carbonic acid Long term measurements taken from ice cores- shows that levels today are higher than the past 420,000 years.
Effects of a Warmer Earth Rising sea levels Cycles of plants and animals changing Tropical diseases, insects and other organisms moving northward Change in ocean currents causing change in weather patterns Heat-related deaths Drought Food shortages
Prevention/Solutions Scientists use computer models to predict changes in the climate IPCC – Intergovernmental Panel on Climate Change – a network of 2,500 of the worlds leading climatologists from 70 countries that provide information on climate change, and make predictions on climate change Kyoto Protocol – requires developed countries to decrease emissions of carbon dioxide and other greenhouse gases by an average of 5% below what it was in 1990s by 2012.