1. Long Term and Short Term Changes in Climate; The Albedo Effect

2. Long Term Climate Change
The Cause and Effects

3. What and How? Long term climate change occurs over million of years.
There are many causes to L.T.C. changes, such as changes in earth’s orbit, shifting of continents, and cycle of climate change

4. Continental Drift The movement of continents.
Climate Change
Continental Drift
The movement of continents.
A long time ago, there was a single continent.
Over millions of years, the continent “broke apart” to form present day Earth.

5. Climate Change
Continental Drift
Movement of land affects the climate in different ways.
Changes in ocean currents, wind patterns and land mass.
The result: heat transfer is affected.

6. Continental Drift.
The Animation.

7. Cycles Not every type of climate change is permanent.
Some occur in cycles.
Changes in Earths orbit also causes changes in climate and it occurs in cycles.

8. Changes in Orbit Specific term: Eccentricity
Causes of long term climate change
Changes in Orbit
Specific term: Eccentricity
The Earth’s orbit around the sun changes shape.
It changes after around years.
The reason: Jupiter and Saturn’s gravitational pull.

9. Causes of long term climate change
Changes in Orbit
When the orbit changes, Earths distance from the sun is either consistent or varied.
When the distance is consistent, the seasons are mild.
When The distance is varied, the climate tends to be more “extreme”.

10. Causes of long term climate change
Changes in Orbit
Change in orbit is a slow transition from almost circular to elliptical.
The change is very slow!
Right now earths orbit is elliptical.

11. Tilt The earth slowly tilts back and forth on its axis.
Causes of long term climate change
Tilt
The earth slowly tilts back and forth on its axis.
The earth tilts around 22.1º to 24.5º.
Happens over years.
Currently, earth is tilted 23.5º.
This angle is decreasing.

12. Climate Change
Tilt
As the tilt increases, the so does the difference in temperature of seasons.
The Earth also “wobbles” around its axis.

13. Short Term Climate Change

14. Short Term Factors Volcanic eruptions Changes in the Sun’s radiation
Changes in air currents
Changes in ocean currents

15. Volcanic Eruptions
Rocks, dust and gases are released into the atmosphere
The sulfur dioxide particles which are released reflect the Sun’s energy back to space
Since there is less energy, the Earth cools down temporarily

16. Volcanic Eruptions
Example on pg. 351 (Fig. 7)

17. Air and Ocean Currents
Changes in thermohaline circulation can cause changes in climate
Thermohaline circulation is the flow of water around the world’s oceans driven by differences in temperature and salinity
There are some changes which occur regularly, an example is El Nino

18. Ocean Currents

19. (cont.) Ocean currents affect climate
Example: The air above warm ocean currents is heated. The land is warmed and rain is produced when this warm, moist air reaches land.
This is why air and ocean currents can affect climate

20. El Nino Occurs every 3 to 7 years
Prevailing winds temporarily change direction
Ocean currents change
Warm water is pushed towards S. America
Because of this, the west coast of S. America gets warm, wet weather

21. El Nino
On pg. 353 (Fig. 8) in textbook

22. The Sun’s Radiation
The amount of radiation the earth receives affects climate
Small changes can affect the climate of the earth
When the amount of radiation is lower, there is less energy, the climate cools
If radiation increases, there is more energy, the climate warms

23. The Albedo Effect

24. Feedback Loops Small changes can have large effects
This is because the small changes can be made bigger because of feedback loops
A positive feedback loop increases the original cause
A negative feedback loop decreases the original cause

25. Water Vapour and Feedback Loops
An example of positive feedback loops is the water vapour in the atmosphere
More water vapour forms since if the climate warms. Water vapour is a greenhouse gas and traps radiation. This further warms up the earth.
It is the same when the climate cools. Less water vapour is formed and the climate cools even more

26. Albedo This is the radiation which is reflected by a surface
Different surfaces have different albedos, an example would be ice which reflects much of the sun’s radiation
The albedo of a planet is a measure of how much radiation is reflected back when the sun shines on it
Earth has an albedo of

27. Albedo Diagram

28. Albedo Effect This is an important feedback loop in Earth’s climate
It is a positive feedback loop
Relationship between ice on surface of the Earth and the avg. temperature
If the temperature increases, ice melts and less radiation is reflected which further increases the temperature
If it decreases, ice forms and more radiation is reflected

29. The Albedo Effect

30. Questions What are the long term changes affecting the earth?
What is continental drift?
What can the movement of large land masses cause?
Does the orbit of the earth change? How?
What are the short term changes which can affect climate?
How do volcanic eruptions cause changes in climate?

31. Questions (cont.) What is albedo? What is the albedo effect?
What happens if the temperature of the planet increases?
What happens if the teperature of the planet decreases?