Chapter 14 Climate
Causes of Climate Change
Describe the natural processes that can cause climate changes
1. Plate tectonics
Geographic changes in the Earth’s land and oceans due to plate tectonics cause changes in climate over very long time scales.
Large supercontinents such as Pangaea developed monsoon climates
Most important, mountain building cooled the global climate. When India collided with Asia, the Himalayan Mountains formed. As the mountain began to erode, sediments washed down into the ocean. The sediments combine with carbon dioxide to form carbonate rocks like limestone. Before the Himalayas, there was three times more carbon dioxide than is on Earth today.
2. Earth’s orbital motion
Changes in the shape of Earth’s orbit and the tilt of the Earth’s axis of rotation affect global climates over intermediate time scales.
Eccentricity
Precession
Tilt
Use this link for eccentricity
Use this link for Earth’s tilt
Use this link to see three ways that Earth’s orbit changes over time
Use this link to see animations of the three ways that Earth’s orbit changes over time
3. Ocean circulation
These changes in ocean circulation also can result in short-term climate fluctuations
Example El Nino is a change in ocean circulation that causes parts of the eastern tropical Pacific Ocean to become warmer than usual.
4. Solar activity
Over short time scales, fluctuations in the amount of solar radiation can change global climates
An increase in sunspots appears to correspond with warm periods in Europe and North America.
Fewer sunspots seem to be correlated with cooler periods. The “Little Ice Age” in Europe during the 1600’s occurred when there were very few sunspots.
What are sunspots?
https://www.youtube.com/watch?v=vsULoSebWnE (0:56)
An Increase in Sunspots could lead to Hotter summers (2:20)
https://www.youtube.com/watch?v=H0t3b23IykY
Sunspots affecting climate change theory/taxes (June 16, 2011) 10:27
https://www.youtube.com/watch?v=JPcdeRVgF78
5. Volcanic eruptions
Volcanic ash, dust, and sulfur-based aerosols in the air increase the amount of solar radiation that is reflected back into space. This causes Earth’s lower atmosphere to cool.
Natural Factors that Affect Climate
Topographic Effects
What is the effect of large bodies of water on climate?
Compare Dallas, TX latitude 32.43 N to San Diego, CA 32.46 N
Link for Dallas
What is the greenhouse Effect?
The natural warming of both Earth’s lower atmosphere and Earth’s surface
What is global warming?
As a result of increases in carbon dioxide levels, as well as other greenhouse gases, global temperatures have increased. This increase is global warming.
What are some consequences of global warming?
Warmer temperatures increase evaporation rates. Increased water vapor in air will magnify affect of greenhouse gases.
Temperature increase will cause sea ice to melt. Ice reflects more of the sun’s radiation than water does. This will substantially increase the amount of solar energy absorbed.
Melting of sea ice and ice sheets will cause a global rise in sea level causing shoreline erosion and coastal flooding.
Weather patterns may change. These would include more severe droughts and heat waves in some areas.
Use this link to see the effect of climate change around the world.
National Geographic Global Warming: A Way Forward: Facing Climate Change – Nat Geo – 24hToday.com 7:43
mhttps://www.youtube.com/watch?v=pAA7FEqYTjA
David Attenborough: ‘Climate Change – Britain Under Threat’ (1:00:14)
https://www.youtube.com/watch?v=Cq1oFhTINXE
Chapter 15 Physical Oceanography
Ch 15.1 The Oceans page 384-391
Objectives:
Discuss the origin and composition of the oceans
Describe the distribution of oceans and major seas
Chapter 15.2 Sea Water pages 392-398
Objectives:
Compare and contrast the physical and chemical properties of seawater
Explain ocean layering
Demonstration:
Before: Two colors of water are separated by a foil barrier.
After: Two holes are punched in the foil: one toward the top and one toward the bottom. Explain.
Ocean water layers because its water masses are different densities. The density of sea water is affect by temperature and salinity.
Temperature
Sea water temperature is affected by latitude and depth. The higher the latitude, the colder the temperature. This is due to the angle at which the sun’s rays strike the Earth. At high latitudes, the sun’s rays are more diffuse, striking a broader area with less intense sunlight. At low latitudes near the equator, the sun’s rays strike a smaller area with more intense sunlight.
Sea water temperature is also affected by depth. The deeper down in the ocean, the colder the water
Salinity
The salinity of sea water averages about 3.5 % but it varies from about 3.3 % to 3.8 %
Several processes affect sea water salinity.
Removing fresh water from sea water causes the water to become saltier. Evaporation and freezing are processes that remove fresh water.
Adding fresh water to sea water causes the water to become less salty. Precipitation, melting of ice, and surface runoff are processes that decrease sea water density.
How do temperature and salinity affect the density of water?
Lab: Modeling Water Masses
What type of water is the…
clear= ____________
blue = ____________
yellow = __________
red = ____________
A red cube and a green ice cube was added to a tray of water. Examine the results. What were the cubes? How do you know?
Describe the formation of deep water masses
Review demonstration:
The “tank” demonstration
- The blue water is cold and salty
- The yellow water is warmer and less salty
- If the red water is warmer than the blue, and saltier than the yellow, predict where the red water will layer and flow in the tank.
http://divediscover.whoi.edu/images/oceancirc_tank.mov
A climate change concern.
How might climate affect the global conveyor belt and how would that affect Europe?
http://www.columbia.edu/cu/record/23/11/13.html
Ocean conveyor belt videos
Woods Hole
http://www.whoi.edu/main/topic/ocean-conveyor
NOAA
http://divediscover.whoi.edu/images/oceancirc_world2.mov
http://divediscover.whoi.edu/images/oceancirc_nac.mov
What makes the great ocean currents flow- career idea
http://www.whoi.edu/main/topic/ocean-conveyor
NASA Earth Science week: Salt of the Earth
mhttp://www.youtube.com/watch?v=EqpJZGyS4Bw
15.3 Ocean Movements
Gyres page 404
- Be able to explain the three causes of gyres
- How are gyres in the southern hemisphere different than gyres in the norththern hemisphere?
- How do gyres regulate the temperature of the ocean and Earth’s climate?
Be able to explain the three causes of gyres
Gyres are large circular surface current systems.
There are 5 major gyres; North Pacific, South Pacific, North Atlantic, South Atlantic, and Indian
Gyres are caused by the Coriolis Effect, the shape of the ocean basin, and prevailing wind patterns
When equatorial currents hit a continent, they are diverted to the poles.
How are gyres in the southern hemisphere different than gyres in the norththern hemisphere?
How do gyres regulate the temperature of the ocean and Earth’s climate?
When currents from low latitude regions move into higher latitude regions, they transfer heat from warmer to cooler areas on Earth.
Gyres review videos:
Animation of gyre:
http://www.roebuckclasses.com/105/animations/wind.htm
Review Videos:
NASA Sci files
NASA Sci files: Density currents:
https://www.youtube.com/watch?v=FuOX23yXhZ8&list=PL65770374240A3EB9
Gyres
https://www.youtube.com/watch?v=YCorkyBe66o&index=5&list=PL65770374240A3EB9
Ocean Heroes: What is a gyre?
https://www.youtube.com/watch?v=h6i16CrI8ss
Ocean Heroes: The Plastic Problem
https://www.youtube.com/watch?v=8BL5o7nRKtE
15.3 Ocean Movements
Objectives:
Describe the physical properties of waves.
Explain how tides form.
Compare and contrast various currents
Ch 14.3 Climatic Changes
Describe the natural processes that can cause climate changes
1. Plate tectonics
Geographic changes in the Earth’s land and oceans due to plate tectonics cause changes in climate over very long time scales.
Large supercontinents such as Pangaea developed monsoon climates
Most important, mountain building cooled the global climate. When India collided with Asia, the Himalayan Mountains formed. As the mountain began to erode, sediments washed down into the ocean. The sediments combine with carbon dioxide to form carbonate rocks like limestone. Before the Himalayas, there was three times more carbon dioxide than is on Earth today.
2. Earth’s orbital motion
Changes in the shape of Earth’s orbit and the tilt of the Earth’s axis of rotation affect global climates over intermediate time scales.
Eccentricity
Precession
Tilt
Use this link for eccentricity
Use this link for Earth’s tilt
Use this link to see three ways that Earth’s orbit changes over time
Use this link to see animations of the three ways that Earth’s orbit changes over time
3. Ocean circulation
These changes in ocean circulation also can result in short-term climate fluctuations
Example El Nino is a change in ocean circulation that causes parts of the eastern tropical Pacific Ocean to become warmer than usual.
4. Solar activity
Over short time scales, fluctuations in the amount of solar radiation can change global climates
An increase in sunspots appears to correspond with warm periods in Europe and North America.
Fewer sunspots seem to be correlated with cooler periods. The “Little Ice Age” in Europe during the 1600’s occurred when there were very few sunspots.
5. Volcanic eruptions
Volcanic ash, dust, and sulfur-based aerosols in the air increase the amount of solar radiation that is reflected back into space. This causes Earth’s lower atmosphere to cool.
Ch 14.1 Factors that Affect Climate
Vocabulary
- Weather
- Climate
- climatology
Objectives:
How do each of the following factors effect climate?
1. Latitude
As latitude increases, the average temperature decreases. See the figure 14-2 on page 362. The tropics are located between ______ degrees North and ______ degrees South. Why do the tropics have a higher average temperature than the Temperate zones located between ______ and ______ degrees North and South of the equator?
2. Elevation
As elevation increases, the average temperature decreases. Air temperature decreases with elevation by an average of about 6.5 degrees C every 1000 meters. If city A is 2,000 meters higher than city B, how much colder will city B be than city A?
Elevation also has an affect on precipitation.
The higher the elevation, the __________________ the precipitation.
3. Topography
Topographic features such as mountains play an important role in the amount of ____________ that falls over an area.
Click this link to see the average precipitation of Seattle, WA
Click this link to see the average precipitation of Spokane, WA
Click this link to see the location of Seattle and Spokane
How does the average rainfall compare between the two cities?
What do you notice about their locations?
Suggest a reason why the the two cities have different amounts of rainfall. Hint: See page 590
Click this link for a mini-lecture explaining a rain shadow. Use the “Light Saber Lecture” NOT the Magic School bus : )
4. Water Bodies
Link for average temperature and precipitation of Vancouver, BC
Link for average temperature and precipitation Winnipeg, Manitoba
http://weather.sg.msn.com/local.aspx?wealocations=wc:CAXX0547&q=Winnipeg%2c+CAN
Click this link to see the average temperature of Winnipeg, Manitoba Canada
Click this link to see the average temperature of Vancouver, British Columbia
Compare the June, July, and August temperatures of the two cities.
Compare the December, January, and February temperatures of the two cities.
The latitude if Vancouver is 49.2505° N and Winnipeg is 49.25° N. They are both at approximately the same elevation. Read page 50. Suggest a reason for the difference in temperature.
5. Atmospheric Circulation
Global winds are another factor that influences climate because they distribute heat and moisture around Earth.
Winds constantly move warm air toward the poles and cool air toward the equator. This helps to regulate Earth’s temperature.
Low pressure areas around the equator and middle latitudes lead to the formation of clouds that drop precipitation as rain or snow.
6. Vegetation
Vegetation patterns can affect both temperature and precipitation patterns in an area. Vegetation influences how much of the sun’s energy is absorbed and how quickly this energy is released. This affects temperature. During the process of transpiration, plants release water vapor from their leaves into the air.
Look at Figure 5 on page 591. Which area, A or B would receive more precipitation? Why?