1. Climatic Changes

2. Causes of Climate Latitude – differential heating
Topographic effects –
Proximity to water
Altitude
Mountain range
Air Masses

3. Climatic Changes
Climate change is a slow process but has occurred multiple times in earth’s history
Ex) Multiple ice ages – periods of cooler climate and extensive glaciers

4. Short-term climatic changes
Ice ages are an example of long-term climate change
Seasons- an example of short-term climate change

5. Seasons What causes them?
The tilt of the earth on its axis. Seasons are NOT caused by distance from the sun.
The hemisphere tilted toward the sun receives more direct radiation. How does this affect intensity?

6. El Nino
Climate changes due to reversing of an ocean current in the Pacific Ocean.
Basically, El Nino can flip climate conditions in many areas.

7. Natural Climate Change
Climate changes have occurred throughout earth’s history
Can be caused by changes in solar activity, earth’s tilt, and volcanic eruptions

8. 1. Solar activity
Relationship between low sunspot activity and colder climates on earth.
Maunder Minimum – low sunspot activity period

9. 2a. Earth’s orbit
Earth’s orbit cycles between circular and elliptical every 100,000 years.
A more elliptical orbit = warmer climate because earth is closer to the sun.

10. 2b. Earth’s tilt
Currently the earth has a 23.5 degree tilt on its axis. Seasons are caused by the tilt changing throughout the year.
The angle varies from 22.1º to 24.5º every 41,000 years.
Less angle = seasons not as drastic

11. 3. Earth’s wobble
The axis of the earth points to a different point every years.
Switches cause summer and winter to be more drastic.

12. 4. Volcanic activity
Big eruptions send a massive amount of dust in the atmosphere. It can remain suspended for years blocking solar radiation.
Cause cooler climate periods
Short term climate change

13. Human Factor
Greenhouse effect – natural heating of earth’s surface caused by certain atmospheric gases (water vapor, carbon dioxide).
The gases trap heat that is radiated by the earth.
It is NOT a human invention.

14. Greenhouse effect
It may be possible to increase or decrease the greenhouse effect by changing the amount of greenhouse gases (CO2)
This is the current controversy

15. Global Warming
Temps have warmed over the last 200 yrs (scientists agree)
Could eventually cause ice caps to melt, coastal flooding, deserts to spread, and more severe storms

16. Global Warming, pg 376!!! Scientists agree that temps are climbing
Do not all agree about why
Natural causes vs. increased CO2 in the atmosphere (artificial or human influences)

17. Increase of carbon dioxide
Burning of fossil fuels
Deforestation
Don’t waste electricity! Recycle!

18. Renewable vs. Nonrenewable
Renewable energy sources – energy from resources that are continually replenished
Examples?
Nonrenewable energy sources – take thousands of years to form. Cannot be replaced as quickly as they are used
Compare and contrast benefits?