Academic journal article Science Scope

Fires, Floods, & Hurricanes: Is ENSO to Blame?

Academic journal article Science Scope

Fires, Floods, & Hurricanes: Is ENSO to Blame?

Article excerpt

From January 1 through October 5, 2006, over 84,000 wildfires occurred in the United States, burning over 9 million acres. In contrast, 50,000 wildfires burned slightly over 3.1 million acres during the same months in 2003. In April 2006, precipitation up to 8 inches above normal caused severe flooding in California. Rains during July and August 2006 sent floodwaters through El Paso, Texas-forcing the evacuation of hundreds of residents-while other parts of the state were experiencing drought. The 2005 Atlantic hurricane season had a record 28 named storms with an unprecedented four reaching category five status. A year later, the hurricane season was back to normal with just 10 named storms (National Hurricane Center 2006). Such extreme climate events occur somewhere in the world every year. In some years, more of these extreme events occur than in other years. Is there a scientific explanation for the increasing occurrence of these events?

Scientists have associated the El Nino/Southern Oscillation (ENSO) phenomenon with extreme climate events such as flooding in California, droughts in Australia, fires in Indonesia, and increased hurricane activity in the Atlantic Ocean. The popular media is constantly attributing individual storms to the ENSO phenomenon. The reality is that a single storm cannot be attributed to ENSO. For example, snowstorms occur in California every year, but no single storm was caused by ENSO. ENSO is, however, related to changes in the probability of precipitation and temperature levels.

Because ENSO is the most highly recognized phenomenon affecting global climate variability, it is important that students learn about it. ENSO refers to the coupled ocean-atmosphere system in the tropical Pacific Ocean. Changes in this system have important consequences for seasonal climate variability worldwide. ENSO as a physical occurrence is a proven fact, as real as snowstorms and thunderstorms. Because most textbooks fail to adequately cover this important topic, an ENSO learning experience was developed that is directed toward middle level students.

The ENSO material is part of a larger learning unit integrating mathematics, statistics, decision making, and climate science. In this article we focus on the ENSO-related material located on the DECIDE website (see Resources), a resource developed by teachers at Texas A&M University and College Station Independent School District with funding from the National Oceanic and Atmospheric Administration (NOAA).

ENSO learning modules

The learning modules available on the DECIDE website provide a fairly complete overview of the ENSO phenomenon. Teaching the modules takes five to eight days depending on the material taught and method(s) used (see Figure 1). The website includes downloadable teacher instructions and student worksheets.

The introductory module begins to develop the students' understanding of ENSO. Unlike the other modules in this unit, this one is best taught as a teacher-directed discussion centered on the "Introduction on Climate Variability Concentrating on El Nino/Southern Oscillation (ENSO)" reading material. For students to be able to understand the material in the next modules, the first two sections of the introduction, "What Is ENSO?" and "ENSO Phases Defined" (El Nino, La Nina, and neutral), must be covered. The last two sections, "Historical Perspective" and "Other Phenomena Affecting Climate Variability," help students recognize science is not perfect and many different phenomena affect climate variability worldwide.

In the science module, students learn the physical science aspects associated with ENSO. There is flexibility in how the module is taught, but it is designed to use the jigsaw approach to learning. The "Expert Readings and Worksheets" are more detailed than the "Combining Experts" worksheets. As an example, the worksheet summarizing the Pacific Ocean aspects of the three ENSO phases is shown in Figure 2. …

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