1. Earth’s climate and how it changes

2. What Factors Affect Climate?
Latitude – distance north or south of equator
Elevation – height above sea level
Topography – features on land
Water Bodies – lakes and oceans
Atmospheric Circulation – global winds
Vegetation – type and amount of plants

3. LATITUDE
Sun strikes Earth’s surface at different angles creates variations in climate

4. Climate Zones Differences in solar energy create climate zones
Tropical zones
Warm all year, 23.5o north to 23.5o south of equator
Temperate zones
Hot summers and cold winters, 23.5o to 66.5o north and south of equator
Polar zones
Cold all year, 66.5o north and south to the poles

5. Energy Transfer
Less solar energy is transferred into atmosphere in polar regions than in tropics
Differences in energy affects weather and climate
Pressure differences produce winds
Affects evaporation rates, cloud formation, air masses, and storms

6. ELEVATION Elevation increases, temperature decreases
approximately -6.5oC every 1000 meters or oF every 3,281 feet
Elevation also determines the amount of precipitation
answer: How does elevation affect temperatures and precipitation? Why?
Mt. Whitney and the Owens Valley, Eastern California

7. Can create a Rain Shadow Effect
TOPOGRAPHY
Can create a Rain Shadow Effect
Humid air moves up a mountain: cools, forms clouds, then precipitates
Moisture is lost, very dry on other side
Think: Can you name a mountain range with a Rain Shadow Effect ?

8. WATER BODIES AND ATMOSPHERIC CIRCULATION
Temperature of water influences atmosphere above it. Water has a higher heat capacity than land.
Global winds distribute heat and moisture around Earth
Look up the term heat capacity

9. VEGETATION
Temperature – vegetation influences how much of sun’s energy is absorbed and released
Precipitation - plants release water vapor and particles into the air creating clouds (the more plants the more humid it is).
Consider: how do you think cutting down the rain forest in Brazil has affected the climate there?

10. Earth’s Orbital Motion
Changes in the shape of Earth’s orbit and the tilt of its axis affects global climates
How elliptical the orbit is varies every 100,000 to 400,000 years
Every 20,000 to 40,000 years the tilt of the axis changes about 3° (less tilt = less difference between seasons)
Notice: how has the Sahara desert changed in the last 8,000 years?

11. Solar Activity
Over a short time scale: changes in the amount of solar radiation change global climate.
More sun spots indicate a warmer sun that causes warming periods on Earth
Fewer sun spots occurred in the 1600’s during the “little ice age” in Europe.

12. Volcanic Eruptions
In the short term volcanic eruptions cause cooling from ash, dust and sulfur- containing particles reflecting sunlight back into space (aerosols).
In the long term it can cause warming by increasing CO2 levels

13. The Greenhouse Effect
The Greenhouse Effect is the warming of the atmosphere by gasses that trap solar radiation.
Water vapor, CO2, and methane are the major greenhouse gasses
Consider: how would increasing methane levels in the atmosphere affect the Earth’s temperature?

14. Summary
Write a 5-8 sentence summary of the factors that affect climate and climate change.