Hurricanes and Climate

Directions

Elicit prior knowledge.

1. Survey student knowledge about hurricanes through class discussion. If students need background about hurricanes, have them use Student Activity Sheet page 1 to organize knowledge and questions as they read the UCAR Hurricanes explainer article.

Where do hurricanes happen?

1. Show the class the Map of Tropical Cyclones 1985-2005. Explain that the lines on the map show the paths of hurricanes and other tropical storms and there are six areas of the world where hurricanes occur. (Note that hurricanes are called tropical cyclones and typhoons in other parts of the world.)
2. Referring to the map, ask students to color the approximate locations of these six regions on Student Activity Sheet page 2 using a different color for each region and then identifying the colors in the map key.
3. As students notice where hurricanes do and do not occur, you may wish to share detail that connects with students' prior knowledge such as:

• Hurricanes are usually over the ocean, which provides warm, moist air that fuels the storms.
• The storms do not form at the equator where there is no rotating Coriolis force.
• They do not form at the poles because it’s too cold for tropical cyclones.

How many hurricanes happen?

1. Looking at the Map of Tropical Cyclones 1985-2005, students will likely notice that there are more hurricane paths in some regions than others. As a class, develop a hypothesis about whether the same number of hurricanes happen in each region.
2. Using the table on Student Activity Sheet page 3, ask students to create a bar graph (histogram) to explain how many hurricanes happen in each region. Ask students if their bar graph supports the idea that hurricanes are not equally distributed between regions.

When do hurricanes happen?

1. Students investigate the seasonal timing of hurricanes on Student Activity Sheet page 4. Have students use the same colors they used for the map to indicate the hurricane season for each region on the timeline.
2. The questions at the bottom of the worksheet are intended to point out that hurricanes happen at different times of year in the Southern and Northern Hemispheres and also that hurricanes happen during the warmest time of year.

Where’s the warm water?

1. Project the Map of Sea Surface Temperatures. Tell students that this map shows the temperature of the water that is at the ocean surface as measured by satellites. Review the key with students.
2. Have students compare the Map of Sea Surface Temperatures with the map they annotated on Student Activity Sheet page 2. Students should notice that hurricanes happen in areas where the ocean water is warm. Remind students that they had also figured out that hurricanes happen at the warmest time of year. Ask students to predict what might happen to hurricanes as our climate becomes warmer.

Is climate warming affecting hurricanes?

1. Introduce the data tables on Student Activity Sheet page 6. The top table shows the total number of hurricanes that happened in each region during three different time periods. The bottom table shows the number of very strong hurricanes that happened during the same time periods.
2. Instruct students to answer the questions on the right side of the page and consider the ideas they generated about how warmer climate could affect hurricanes.

Are hurricanes getting stronger?

Students represent the data from the lower table (strong hurricanes) in small bar graphs and then interpret the graphs to draw conclusions during the summary discussion. (See sample questions below.)

1. Does this data indicate that there are more hurricanes now?
2. Does this data show that there are more stronger storms?
3. Why might climate warming cause changes in hurricanes?
4. What other information would you like to have to know whether climate change is the cause?