1. Climatic Changes

2. Standards 4d: Students know the differing Greenhouse conditions on Earth, Mars and Venus; the origins of those conditions; and the climatic consequences of each. 4d: Students know the differing Greenhouse conditions on Earth, Mars and Venus; the origins of those conditions; and the climatic consequences of each. 5g: Students know the features of the ENSO cycle in terms of sea-surface and air temperature variations across the Pacific and some climatic results of this cycle. 5g: Students know the features of the ENSO cycle in terms of sea-surface and air temperature variations across the Pacific and some climatic results of this cycle.

3. Seasons Short-term periods of climate change caused by regular variations in daylight, temperature and weather patterns Short-term periods of climate change caused by regular variations in daylight, temperature and weather patterns Variations are due to changes in the amount of solar radiation an area receives Variations are due to changes in the amount of solar radiation an area receives Once Earth revolves at a tilt, different areas of earth receive changing amounts of solar radiation Once Earth revolves at a tilt, different areas of earth receive changing amounts of solar radiation

4. Seasons

5. Effects of Latitude Middle latitudes have fairly constant solar radiation so there is little change in seasons. There are changes in wet and dry seasons Middle latitudes have fairly constant solar radiation so there is little change in seasons. There are changes in wet and dry seasons Higher latitudes near the poles experience great differences in temperature and in number of daylight hours. Higher latitudes near the poles experience great differences in temperature and in number of daylight hours.

6. South & North Poles During the summer the North Pole is tilted toward the sun, at this location there are 24 hours of daylight for six months During the summer the North Pole is tilted toward the sun, at this location there are 24 hours of daylight for six months At the same time in the South Pole experiences 24 hours darkness At the same time in the South Pole experiences 24 hours darkness

7. El Nino Occurs every three to five years and lately more often Occurs every three to five years and lately more often During El Nino the Pacific Ocean warms along the equator During El Nino the Pacific Ocean warms along the equator Near the equator trade winds blow east to west weaken and sometimes reverse. Near the equator trade winds blow east to west weaken and sometimes reverse.

8. El Nino Cont. Instead of cold water rising off the coast of Peru, the change in the trade winds allows warm tropical water in the upper layer of the Pacific to flow eastward to South America Instead of cold water rising off the coast of Peru, the change in the trade winds allows warm tropical water in the upper layer of the Pacific to flow eastward to South America Ocean temperatures increase by 1 degree C to 7 degrees C off the coast of Peru. Ocean temperatures increase by 1 degree C to 7 degrees C off the coast of Peru. Sea levels rise Sea levels rise

9. However, El Nino….. Does not directly cause unusual weather but instead affects the atmosphere and the ocean to make stormy weather more likely. Does not directly cause unusual weather but instead affects the atmosphere and the ocean to make stormy weather more likely.

10. Climatic Change Earlier geologic eras show that Earth was sometimes much colder or warmer than it is today Earlier geologic eras show that Earth was sometimes much colder or warmer than it is today Glaciers have covered large parts of Earth’s surface Glaciers have covered large parts of Earth’s surface These periods of extensive glaciers are called ice ages These periods of extensive glaciers are called ice ages Ice ages alternate with warm periods called interglacial intervals Ice ages alternate with warm periods called interglacial intervals

11. Greenhouse Effect Natural heating caused by gases in our atmosphere trapping heat Natural heating caused by gases in our atmosphere trapping heat Carbon dioxide is the main greenhouse gas Carbon dioxide is the main greenhouse gas

12. Global Warming Global temperatures are rising Global temperatures are rising Increased greenhouse gases increase the greenhouse effect Increased greenhouse gases increase the greenhouse effect Temperatures on Earth have risen ½ degree C in the last 100 years Temperatures on Earth have risen ½ degree C in the last 100 years

13. Global warming has a huge effect on Earth!

14. Greenhouse warming

16. What about other planets? Venus Venus –Most similar to earth in physical properties such as mass, diameter and density –Average surface temperature is 464°C –The atmosphere is mainly Carbon Dioxide and Nitrogen. Causes a highly efficient Greenhouse Effect resulting in very high temperatures. Causes a highly efficient Greenhouse Effect resulting in very high temperatures. –It has clouds made of sulfuric acid –The atmospheric pressure is 92 atmospheres, compared to 1 atmosphere at sea level on Earth.

17. What about other planets? Mars Mars –The planet is smaller and less dense than Earth. –The density and atmospheric pressure on Mars is much lower than Venus –There is a very thin atmosphere 95% Carbon Dioxide 95% Carbon Dioxide 5% Oxygen, Nitrogen, Argon 5% Oxygen, Nitrogen, Argon –Because of this Mars does not have the strong Greenhouse Effect found on Venus. –Mars has high turbulent winds

18. The Coriolis Effect It is important because: It is important because: It controls the global circulation patterns of the atmosphere It controls the global circulation patterns of the atmosphere –Climate zones –Rainfall patterns –Surface wind patterns It affects global ocean circulation patterns It affects global ocean circulation patterns –Coastal currents –Westward intensification of coastal currents –Heat transport from equator to the poles It affects ocean mixing through the Eckman Spiral It affects ocean mixing through the Eckman Spiral –Upwelling –Surface mixing

19. To understand Coriolis, we: Use the analogy of a carousel with two people playing catch. Use the analogy of a carousel with two people playing catch. The carousel rotates during the game The carousel rotates during the game –Analogous to earth rotation We observe the game of catch as if we were seeing it from: We observe the game of catch as if we were seeing it from: –1. A high, fixed platform (analogous to outer space). –2. A platform that rotates with the carousel (analogous to our location on the rotating earth). –Play Video

20. Limitations of the analogy: The analogy is that the earth is represented by the carousel and the “fixed” observer is an “inertial” frame of reference, where objects travel in straight lines. The analogy is that the earth is represented by the carousel and the “fixed” observer is an “inertial” frame of reference, where objects travel in straight lines. The observation is from above, so it only applies to the earth if the carousel is at the north or south pole. The observation is from above, so it only applies to the earth if the carousel is at the north or south pole.

21. Coriolis on the Earth Mass in motion curves to the right in the Northern Hemisphere and to the Left in the Southern Hemisphere. Mass in motion curves to the right in the Northern Hemisphere and to the Left in the Southern Hemisphere. The Coriolis effect is strongest at the poles and weakest at the equator. The Coriolis effect is strongest at the poles and weakest at the equator.

23. Atmospheric Circulation if earth doesn’t rotate If the earth were a non- rotating sphere, air circulation would be in a single Northern Hemisphere cell and in a single Southern Hemisphere cell. In each cell, heated air would rise at the equator and move toward the polar regions, where it would cool, sink, and be drawn back to the warmer regions of the equator.

24. Review Sheet What are seasons? What are seasons? Explain how the tilt of the earth effects seasons. Explain how the tilt of the earth effects seasons. How does El Nino occur? How does El Nino occur? What is the effect of El Nino? What is the effect of El Nino? In depth explain the Greenhouse effect and the impact of earth. In depth explain the Greenhouse effect and the impact of earth. Why is global warming occurring and how does it effect earth? Why is global warming occurring and how does it effect earth?