atmosphere and climate change ch.13
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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?. Earth and Human Systems. Global Temperatures are Increasing. - PowerPoint PPT PresentationTRANSCRIPT
Atmosphere and Climate Changech.13Why You Should Care:Popular Issue – interestingAffects federal policy, global policyAcademic StudyIt is a realityCan we do something about it?
Earth and Human Systems
Global Temperatures are Increasing
http://data.giss.nasa.gov/gistemp/graphs_v3/Fig.A2.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?LatitudeAtmospheric circulation patterns
Oceanic patternsLocal geographySolar activityVolcanic 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_SolarEnergy.html
2. Atmospheric CirculationCold 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 Earth’s precipitation pattern
Atmospheric circulation driven by uneven heating of the Earth by the Sun
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, cont’dPrevailing winds – blow predominantly in
one direction, not directly northward or southward (because of Earth’s 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 CirculationThe 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
Ocean Circulation
Surface Currents that changeEl 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 Australia3. http://www.esrl.noaa.gov/psd/map/clim/sst_olr/el_nino
_anim.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. TopographyTemperatures fall by 11* F for every 1,000
m. increase in altitudeRain shadow - Rain on West side of
Mountain – dry on East.Water cools and warms faster than landhttp://www.newton.dep.anl.gov/askasci/env
99/env99395.htm
Rain Shadow
Other Influences on Earth’s ClimateSolar 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 ClimateSeasons are a result of the 23.5* tilt in
Earth’s axis.Because of the tilt, the sun’s 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
Seasonal Changes in Climate
POP QUIZ SEC. 1answer on ¼ sheet of paper and turn in1.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 ShieldOzone – O3
The ozone layer is in the stratosphere and absorbs harmful UV rays from the sun.
CFC’s – chloroflourocarbons – coolant in refridgerators and air conditioners, and propellent in spray cans.
CFC’s break apart in the stratosphere and destroy ozoneA 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 Formationhttp://www.theozonehole.com/twenty.htmEffects of ozone thinning on humans: UV damages DNA can cause skin cancerEffects of ozone thinning on plants and
animals: kills phytoplankton – provides most of the
oxygen on earthHarms amphibian eggs – amphibians are
indicators of healthy/unhealthy ecosystemInterferes with photosynthesis of plants
Protecting the Ozone Layer1987 Montreal Protocol – nations agreed to
put limit on CFC emissions1992 – developed countries agreed to
eliminate all CFC’s by 1995CFC’s remain active in stratosphere for 60-
120 years
Sec.3 Global Warmingan 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 atmosphereMeasured at Mauna Loa, Hawaii Most CO2 released is 1) dissolved in the
ocean 2) absorbed by plantsCO2 increases acidity in oceans – it
combines with water to make carbonic acidLong term measurements taken from ice
cores- shows that levels today are higher than the past 420,000 years.
Effects of a Warmer EarthRising sea levelsCycles of plants and animals changingTropical diseases, insects and other organisms moving
northwardChange in ocean currents causing change in weather
patternsHeat-related deathsDroughtFood shortages
Prevention/SolutionsScientists use computer models to predict
changes in the climateIPCC – Intergovernmental Panel on Climate
Change – a network of 2,500 of the world’s 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 1990’s by 2012.