Chapter 17 Climate

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Chapter 17Climate

• Climate is the pattern of weather that occurs in
  an area over many years. It determines the types
  of plants or animals that can survive, and it
  influences how people live.
• Factors that affect climate include temperature,
  precipitation, air pressure, humidity, and number
  of days of sunshine, latitude, landforms,
  location of lakes and oceans, and ocean currents.

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Latitude and Climate

• Because solar radiation hits the equator
  directly, the area between 23.5o N and 23.5o S is
  called the tropics.
• The area between 66.5o N and S and the poles is
  called the polar zones.
• Between the polar zones and the tropics are the
  areas called the temperate zones,
• where temperatures are moderate.

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Other Factors that Affect Climate

• Large Bodies of water create more moderate
  ranges in temperature because water holds heat
  longer, and takes longer to heat up. Water has a
  high specific heat capacity.
• Ocean currents warm currents begin near the
  equator and flow towards higher latitudes warming
  land. When flowing toward the equator, they cool
  off and cool the land.
• Mountains are higher in altitude and contain
  fewer air molecules to absorb the heat, thereby
  cooling the climate.
• Rain Shadows rain occurs on windward sides of
  mountains dryness on leeward side creating
  deserts.
• Cities paved areas heat up affecting climate
  and air pollution traps heat causing cities to be
  about 5oC warmer than surrounding rural areas.

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Section 2 Climate Types

• Climatologists-people who study climates
• 1918-Wladamir Koppen designed a system for
  classifying climates based on the types of plants
  found in a region. He did this by using the
  temperature and precipitation of regions that had
  different plant types.
• Climates are classified into 6 groups
• Tropical, mild, dry, polar, high elevation, and
  continental
• Further separated into types

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Adaptations

• Any behavior or structure that helps an organism
  survive in its environment
• Inherited
• Once adapted to a particular environment,
  organisms may not be able to survive in other
  climates.
• Structural adaptations include fur, thick stems
  on plants, spiny leaves
• Behavioral adaptations include hibernation,
  clustering together, hiding under
• rocks, estivation, sweating, shivering

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Section 3 Climatic Changes

• Because Earth is tilted, different areas of Earth
  receive changing amounts of solar radiation
  throughout the year-SEASONS.
• Tropics-not much seasonal temperature change
  because of latitude. Days are about the same
  length all year.
• Temperate zones -warm summers and cool winters
• High latitudes -during summer at North Pole, sun
  does not set for nearly 6 months sun never rises
  at the South Pole during that same time

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El Nino

• El Nino is a climatic event that involves the
  tropical Pacific Ocean and the atmosphere.
• During normal years, strong trade winds that blow
  east to west along the equator push warm surface
  water toward the western Pacific Ocean.
• During El Nino years, these winds weaken and
  sometimes reverse. This allows tropical water to
  flow back eastward to South America. Ocean
  temperatures increase from about 1oC to about 7oC
  off the coast of Peru.
• El Nino can affect weather patterns by altering
  jet streams. It can cause drought in Australia
  and Africa, storms in California, and monsoon
  rains in Indonesia.

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La Nina

• During La Nina, the winds blowing across the
  Pacific are stronger than normal causing warm
  water to accumulate in the western Pacific.
  Water in the eastern Pacific is cooler than
  normal.
• Can cause droughts in the southern U.S.
• Can cause excess rainfall in the northwestern U.S.

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Climatic Change

• Ice ages seem to last 60,000 to 100,000 years.
• Interglacial periods are shorter, about 10,000 to
  15,000 years. We are now in an interglacial
  period that began about 11,500 years ago.
• Ice cores drilled in Greenland show that during
  the last ice age, colder times lasting 1,000 to
  2,000 years changed quickly to warmer spells
  lasting about the same length of time.

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Causes of Climatic Change

• Meteorite collisions
• Large volcanic eruptions
• Short and long-term changes in solar output
• Changes in Earths movement in space
• Movement of Earths crustal plates

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What causes changes in climate?

• Atmospheric solids and liquids
• Humans add from automobile and smokestack
  emissions
• Fires
• Volcanic eruptions
• Meteorite collisions
• Wind erosion
• Energy from the sun
• Earths tilt on its axis changes and wobbles, and
  orbit shape changes
• Crustal plate movement -movement of oceans and
  plates affect the transfer of heat

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Changes in Climate Today

• Greenhouse effect a natural heating that occurs
  when certain gases in Earths atmosphere trap
  heat.
• Water vapor, carbon dioxide, methane
• too littlegtEarth would be too cold to live
  Mars
• -too muchgtEarth would be too warm to live Venus

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Global Warming
Average global temperature of Earth is rising.

• During past 100 years, surface temperature on
  Earth has increased 0.6oC.
• Atmospheric CO2 has increased by 20.
• Glaciers can melt causing a rise in sea level.
• Warming can affect organisms survival. (coral)

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Human Activities

• Humans affect the air in Earths atmosphere.
• Burning fossil fuels-natural gas, oil, coal form
  CO2 in air
• Deforestation destroying and cutting down trees
  for mining, roads, buildings, and grazing cattle
• Tropical forests are decreasing at a rate of 1
  per year for the past 2 decades.

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Carbon Cycle