Exploring the Link Between Hurricanes and Climate Using GCM Results
University of Northern Colorado
This activity requires students to examine global climate model output available online and consider the potential impact of global warming on tropical cyclone initiation and evolution. As a follow-up, students read two short articles on the connection between hurricanes and global warming and discuss these articles in context of what they have learned from model output.
This activity is designed for an upper-division Physical Climatology course for Meteorology majors (~15-20 students). This could also be used in a Global Change or Environmental changes course for science majors. Aspects of this activity could be tailored for students at a more introductory level, although lower level students will require significant guidance in analysis of climate model results.
Skills and concepts that students must have mastered
Students should have a basic understanding of factors involved in hurricane growth and evolution, as well as an understanding of the factors that affect climate change. Students should also be somewhat familiar with climate models (in terms of their utility, and what types of information they provide).
How the activity is situated in the course
This activity is introduced as a stand-alone exercise near the end of the semester, after we have covered extensively radiative transfer, the hydrologic cycle and global oceanic and atmospheric circulation. Students have been reading journal articles on various topics throughout the semester for homework and class discussion, so they are familiar with the scientific journal article format.
Content/concepts goals for this activity
Understand which aspects of changing climate will impact hurricanes (SSTs, lapse rate, upper level winds)
Consider the impact of climate change on hurricanes
Understand how scientists go about examining trends in tropical cyclone activity
Higher order thinking skills goals for this activity
Examine climate model output from the NCAR Community Climate System Model (available online)
Develop a hypothesis regarding the effect of climate change on hurricanes
Synthesize ideas about hurricanes and climate as presented in a journal article
Other skills goals for this activity
Provide an oral summary of individual group analysis for the rest of the class
Develop a short written and oral summary of a journal article
Formulate questions/hypothesis about the relationship between hurricanes and climate change in the future
Description of the activity/assignment
This is a two part activity, requiring two to three 50-minute class periods. During the first class period, students review the factors affecting tropical cyclone initiation and evolution (role of sea surface temperatures, etc), then examine output from NCAR's Community Climate System Model experiment which tested model climate sensitivity to 4x 1990 atmospheric CO2 levels. In groups, students compare the 4xCO2 experiment with a 1990 Control experiment in terms of surface temperature, upper level winds, and lapse rate in hurricane-prone regions. Each group considers whether tropical cyclones would be more likely to develop in the 4xCO2 experiment, then provides a brief oral report to the class on the result of their discussion. For homework, students read two short journal articles examining the connection between hurricanes and climate change. In preparation for discussion on these articles, students create a brief written summary of the main points in each article and a list of discussion questions. Class discussion is driven by students' written summaries and questions. Students consider the hypotheses developed in the previous class regarding hurricanes in a warmer world in context of what they have read in the articles.
Determining whether students have met the goals
A student who is successful with this assignment will demonstrate the following:
- A clearly articulated (both oral and written) hypothesis regarding hurricanes and global warming based on sound scientific reasoning
- Understanding of the physical processes involved in hurricane initiation and evolution (as evidenced by their ability to describe such processes on an exam)
- The ability to summarize the main points of a scientific journal on a homework assignment
- The ability to formulate questions about a scientific journal article that go beyond details about vocabulary or the meaning of a particular figure (as evidenced through homework and class discussion)
- The ability to synthesize new information about tropical cyclone trends (from articles, and re-evaluate their hypothesis regarding the effect of climate change on cyclones). Students will be evaluated informally on this point through class discussion.
Teaching materials and tips
Template for Student Handout (Microsoft Word 34kB Oct23 08)
Instructor Notes (Acrobat (PDF) 110kB Oct23 08)
This activity has supplemental information submitted as part of the InTeGrate Teaching the Methods of Geoscience workshop in June 2012.
The NCAR Community Climate System Model: http://www.cesm.ucar.edu/
Emanuel, K., 2005. Increasing destructiveness of tropical cyclones over the past 30 years. Science, 436, p. 686-688.
Webster, P.J., et al., 2005. Changes in tropical cyclone number, duration, and intensity in a warming environment. Science, 309, 1844-1846.