3. Factors that Affect Temperature
1) Latitude
•    Areas close to the equator receive direct raysÂ
(warmer).
•    In Polar Regions, sun’s rays are not as direct. Â
(cooler temperatures).
14. Factors that Affect Precipitation (2 factors)
1) Prevailing winds
• They tend to blow from one direction
• Influences climate
• Moisture content may vary:
a) Warm air holds more moisture than cold air.
b) Winds from rising warm air tend to bring precipitation
c) Winds from rising cold air tend to bring little precipitation.
• Direction form which wind blows
a) land breeze – dry Ex. Sahara desert in Africa
b) sea breeze – moisture Ex. England, Scotland, Ireland.
15.
16. 2. Mountain Ranges
• Act as a barrier to winds and precipitation
a) Windward side – side facing wind receives more
precipitation (wet).
b) Leeward side – side facing awy from wind receives less
precipitation (dryer).
Process:
1) Moist Air moves up windward side – cools, dropping
precipitation.
Moves over mountaintop to leeward side bringing dryer air.
There is little precipitation.
Example: Sierra Nevada mountain range: western side is moist, east side is
dry.
25. 2) Temperate (USA)
• Middle latitude/60° - 30° latitude
• average precip of rain (year round) and
snow (winter) is about the same
• Temps vary: 5° C - 20° C
26.
27. 3) Tropical (Hawaii, Caribbean)
• Low latitude/30° N and S to the equator
• Highest temperatures (does not fall
below 18° C)
• High humidity
• No winter
32. Changes in Climate
What causes the climate to change?
3 natural factors:
1) slow drifting of continents
2) changes in the sun’s energy output
3) variations in the position of the Earth relative to the sun,
collectively known as the “Milankovitch Cycles.”
33. 1. Ice Ages
•Periodically, the Earth’s surface have been covered enormous
sheets of ice.
•4 major ice ages (major glaciations) during the past 2 million
years.
•Average temperature was about 6° C below today’s avg. temp.
•Lasts about 100,000 or more. The most recent began about 1.75
mya and ended 10,000 ago.
•Time period between major glaciations are called interglacials.
(warm period - today)
What kind of life existed?
35. 2. Drifting Continents
• Approximately 200 mya, Pangaea started to drift.
• Plate tectonics.
• Temp and precip dropped.
• Moves only a few cm/yr. So, climate changes will
happen over millions of years.
Where did our present continents originate from?
36.
37. 3. Extinction of Dinosaurs
Â
Possible reasons:
1) Dinosaurs could not adapt to the slow change in climate. Â
2) Many plants became extinct.
3) Asteroid struck the Earth 65 mya.  This resulted in enormousÂ
clouds and dust worldwide blocking the sun’s rays. Â
Temperatures dropped.
Actually, the real reason why dinosaurs became extinct is
because of…
38.
39.
40. 4. Variations in Radiant EnergyÂ
Some scientists believe the sun’s energy output changes over time,Â
affecting the Earth’s temperature.  But there is no evidence.
5. Global Warming
•     Human activity may have influenced the climate.
•     Fossil fuels – coal, oil, and natural gas.  These release aÂ
greenhouse gas -  CO2 (Carbon Dioxide) which traps heat in theÂ
atmosphere.
•     In the past 25 years, CO2 levels have increased by 8%.  If thisÂ
continues, an increase of 2° C can be drastic.