1. Warm Up 4/15
Where are dry-summer tropical climates found in the United States?
a. Utah c. Texas
b. Arizona d. California
Another name for a semi-arid climate is ____.
a. steppe c. highland
b. desert d. tundra
The rain shadow effect is associated with ____.
a. rivers c. latitude
b. mountains d. oceans
Answers: 1) d. 2) a. 3) b.

2. Climate Changes
Chapter 21, Section 3

3. Natural Processes That Change Climate
The presence of aerosols (volcanic ash, dust, and sulfur-based aerosols) in the air increases the amount of solar radiation that is reflected back into space, causing Earth’s lower atmosphere to cool
Changes in ocean circulation (such as El Niño) also can result in short-term climate fluctuations
The formation of sunspots, increased solar activity, appears to correspond with warm periods in Europe and North America
Geographic changes in Earth’s land and water bodies, caused by plate tectonics, cause changes in climate
Changes in the shape of Earth’s orbit and the tilt of Earth on its axis are other Earth motions that affect global climate

4. Volcanic Eruptions

5. Ocean Circulation

6. Concept Check
Identify four natural processes that can result in climate changes.
Volcanic eruptions, changes in global ocean circulation, solar activity, and certain Earth motions can cause changes in climate.

7. The Greenhouse Effect
Greenhouse Effect – a natural warming of both Earth’s lower atmosphere and Earth’s surface
The major gases involved in the greenhouse effect are water vapor and carbon dioxide
The greenhouse gases are transparent to incoming solar radiation, but are good absorbers of Earth’s radiation
The gases maintain warm temperatures in the lower atmosphere, making Earth habitable for living things
Studies indicate that human activity over the past 200 years have strengthened this effect

8. Global Warming
Global Warming – global temperatures increasing as a result of increases in carbon dioxide levels, as well as other greenhouse gases
Scientists base their predictions about global warming on computer models of change in Earth’s atmosphere, called climate models
Warmer surface temperatures increase evaporation rates, increasing the amount of water vapor in the atmosphere, therefore magnifying the effect of carbon dioxide and other gases
Temperature increases will cause sea ice to melt, a big reflector of solar energy, causing more solar energy to be absorbed at the surface
Scientists predict more intense heat waves and droughts in some regions and fewer such events in other places

9. Energy Consumption in the U.S.

10. Carbon Dioxide Concentrations

11. Global Temperature Variations

12. Concept Check What are some of the possible effects of global warming?
Short-term and long-term changes in temperature and precipitation patterns that can result in both wetter-than-normal periods and drier-than-normal periods; a rise in sea level; an increase in shoreline erosion

13. Assignment Read Chapter 21, Section 3 (pg. 600-603)
Do Chapter 21 Assessment #1-32 (pg )
For Section 3: #’s 4, 5, 17-20, 30-32
Study for the Meteorology Unit Test and Quarter 3 Benchmark!!!
Put together 15 lectures (including this one) and 10 warm ups (they should be on the same page as your lectures!)