Rhetorical Analysis Draft: The Trend of Increasing Tropical Storm Destructiveness in relation to Typhoon Haiyan/Yolanda

             Greg Laden of the popular website scienceblogs.com uses the research from Kelly Emanuel’s  Increasing destructiveness of tropical cyclones over the past 30 years to demonstrate how the severity and destructiveness of Typhoon Haiyan in the Philippines had been significantly increased by the changes in sea surface temperatures and increase temperatures at lower depths. Both Emanuel and Laden state that global warming accounts for the increase in frequency and magnitude of tropical storms. Laden uses this as evidence to support his theory that global warming is playing a vital factor in both the deadliness of storms and that global warming is also a key factor in past storms such as Hurricane Katrina and may be the cause of soon to come “megastorms” (Laden).

                The article on scienceblogs.com serves two main purposes: inform the general public to a trend that seems to explain how global warming in in fact a very real factor in the deadliness of storms and the second is a call to action for the acknowledgment of this factor and to have people take a stand against it. In order to do this, Laden utilizes a various set of approaches from statistics, visual representations, to taking a persuasive tone in convincing people that “changes to our climate can kill thousands of people at a time.”

               Laden’s article begins by enumerating the vast different factors that are taken into account when determining the intensity of a tropical storm but emphasizes the significance of one factor in particular- sea surface temperatures.  All the graphs from Emanuel’s work support the theory that the temperatures in the Pacific index are proportional to the destructive capabilities of tropical storms. Laden goes on to say that “sea surface temperatures that was almost certainly caused by global warming, as part of a general warming of the ocean.” Kerry Emanuel’s research does accredit this upturn to “to global warming, suggesting that the upward turned in tropical cyclone PDI values is at least partially anthropogenic.”  To make the topic more understandable to the younger or less scientifically informed audience, Laden uses the analogy of a “working downtown population” growing hungrier. In order to further make the research understandable, the piece also incorporates a set of maps showing the temperatures of waters in the Pacific area. Laden also continues to highlight how global warming is the source of the increase in storms. The focus of the work eventually sees a shift from “one of the most powerful tropical cyclones” to “it is time for action.”  Thus, Laden’s main exegiance for the piece is the need to take action and refute “climate science denialists” by taking action.

                Kerry Emanuel’s Increasing destructiveness of tropical cyclones over the past 30 years goes in depth on the fundamentals mentioned in Laden’s piece and further extrapolates from a scientific standpoint as to how these storms can be mathematically derived and the functionality of these formulas. In addition, to address Emanuel’s audience, Emanuel explains in great detail each of her graphs and relays them back to her initial thesis that “Theory and modellin2 predict that hurricane intensity should increase with increasing global mean temperature… results suggest that future warming may lead to an upward trend in tropical cyclone destructive potential, and—taking into account an increasing coastal population—a substantial increase in hurricane-related losses in the twenty- first century.”

      Although similar in topic, Emanuel’s work focuses on the mathematical and statistical component of how SST or sea surface temperature has been a factor in the increase of the occurrence of storms as well as the intensity of these occurrences in the past thirty years. In order to do this, Emanuel centers the work on the data taken and derives the following formula to show the “PD” or “power dissipated by a storm over its life


        Using similar equations and graphs, the work demonstrates precautions taken to limit the variability of said presented equations. Essentially, this work documents and records the trend of how global warming increases the storms, their yearly frequency, and overall damage done. However, contrary to Laden’s title about a possible trend, Emanuel’s work states that “Global climate model predictions of the influence of global warming on storm frequency are highly inconsistent, and there is no detectable trend in the global annual frequency of tropical cyclones in historical tropical cyclone data.” Thus, it is hard to say if Laden’s article really does a suitable job in explaining to the public of how these disasters function.

        Both the article and the paper focus on the destructiveness and the frequency of storms, but both works offer very different information. Laden’s post suggests that there is a possible trend but makes no real correlation between the two besides the fact that global warming is a major factor in the issue. In contrast, Emanuel’s paper does as the title is stated and elaborates on how data supports the theory that storm destructiveness has increased over the last thirty years and is bound to increase- just not in any “trend” or predictable fashion. In addition, Laden tries to state that the main source of for changes in hurricane/typhoon intensity is the sea surface temperature whereas Emanuel states that “Tropical cyclones do not respond directly to SST, however, and the appropriate measure of their thermodynamic environment is the potential intensity, which depends not only on surface temperature but on the whole temperature profile of the troposphere.” Both pieces do agree on one key issue though: this matter does require attention. Laden feels it is time to “take action” against global warming while Emanuel takes a much more well-rounded approach and concludes that “Whatever the cause, the near doubling of power dissipation over the period of record should be a matter of some concern, as it is a measure of the destructive potential of tropical cyclones.”

      Both Emanuel and Laden’s work serve to inform the world to the destructiveness of storms, but only one actively provides evidence to the destructive forces and supports the theory that storms will become more frequent and even more disastrous. However, Landen simply gives a brief synopsis of the topic and simply assigns most of the blame to global warming, which is not an accurate claim in comparison to Emanuel’s research. 


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