Atlantic Hurricanes Are Getting Stronger, Faster, Study Finds

 News Article (The New York Times): https://www.nytimes.com/2023/10/19/climate/hurricane-intensity-stronger-faster.html?searchResultPosition=4

Scientific Article (Nature): https://www.nature.com/articles/s41598-023-42669-y

Published: October 19th, 2023

    Andra J. Garner, the author of the scientific article, talks about tropical cyclone (TC) intensification rates and how they are increasing over time. The study has two main parts: the three different time periods that the author identifies and the amount of time elapsed over a TCs lifetime. The three time periods are the "historical era" (1971-1990), the "intermediate era" (1986 - 2005), and the "modern era" (2001 - 2020). The three time blocks that the author used for the study are 12 hrs, 24 hrs, and 36 hrs. The author identified TC intensification rates over 12 hrs, 24hrs, and 36 hrs for various storms in each era she described. Intensification rate is defined as the rate at which a TC's wind speeds increase over each of the given blocks of time. The study looks at the maximum intensification rates over a given block of time as well and compares them over the three eras. The maximum intensification for a TC is decribed as the greatest increase in wind speed (given in knots, which has units of kts) in a given block of time during the lifetime of the storm. 

    Delger Erdenesanaa, the author of the news article, seems to use Garner's study more of as a source for her own narrative rather than describing and relaying the finindgs of Garner's study. Erdenesanaa references two other experts in the field and makes sure to point out the fact that neither of them were involved in Garner's study. It seems like she is trying make her own point about climate change and the warming of the oceans and how we're trending in the wrong direction and is using Garner's study as evidence for her claim. The first half of her article describes some of the results of Garner's study, mainly focusing on very specific statlines that support her argument. I'm not trying to say that she's taking Garner's study out of context but there's more behind the results that Erdenesanaa puts in her article. 

    The original scientific article describes a very important distinction in the eras it describes. The eras overlap with each other but it was done intentionally to show two things. First reason is to account for the fact that TC tracking methods changed in between eras and the data Garner gathers will be a mixture of all tracking methods. The second reason is to show the slow progression of the intensification rates over time so a proper chart can be made of the data. To quote from the paper, "the mean maximum intensifcation rates for a 12-h window increase by about 28.7% from the historical era (12.2 kts) to the modern era (15.7 kts). Similarly, mean maximum intensifcation rates across 24-h windows grow by about 27.1% from the historical era (17.7 kts) to the modern era (22.5 kts), and mean maximum intensifcation rates across 36-h windows increase by about 26.3% from the historical era (21.3 kts) to the modern era (26.9 kts). These increases are signifcant at a 90% credible interval." What this is saying is that from the historical area to today's modern area, there has been a statistically significant increase in the mean maximum intensification rates in all windows of time. One thing the paper does note is that the results from the intermediate era to the modern area are not statistically significant but a steady increase in the mean maximum intensification rates can be seen over these periods. 

"This figure shows probability density functions of tropical cyclone intensifcation rates. Distribution of tropical cyclone intensifcation rates for the historical era (1971–1990; purple), intermediate era (1986–2005; teal), and modern era (2001–2020; orange). Distributions of peak intensifcation rates are shown for (A) 12-h windows, (B) 24-h windows, and (C) 36-h windows. The mean for each distribution is shown by a dashed line, with shading to show the 90% credible interval surrounding the mean."

    The scientific article also talks about how the rising intensification rates are also leading to a rise in TCs developing into more dangerous storms. This is described as weak and major TCs where a weak TC is category 1 and below and a major TC is category 3 and above. This part of the paper is where Erdenesanaa got the data for her introdcutory statements. She says in the news article that, "hurricanes in the Atlantic Ocean are now twice as likely to grow from a weak storm into a major Category 3 or higher hurricane within just 24 hours, according to a study published Thursday. "The scientific article reports this data in the form of percentage of peak intensification that result in storm going from weak TCs to major TCs. Over the 24hr time frame the percentage went from 3.23% to 8.12%, over the 36hr time frame it went from 4.23% to 10.3%, and over the 12 hr window it went from 1.06% to 3.58%. These were all comparing the increase from the historical era to the modern era and as you can see the percentages have more than doubled in all time windows. 

     Two more points that Garner makes in her paper is the fact that more intense TCs are affecting certain areas due to the rising sea surface temperature and the probability that a TC will exceed certain intensification rates has increased. First the heat map data has shown that the rising sea temepratures are fueling these stroms to develop into stronger TCs. Specifically, Garner shows that this will effect the southeast coast of the U.S. and the Caribbean Islands the most. Erdenesanaa also uses this fact to support her view in her article about calling attention to the drastic warming of the ocean. Garner also showed that TCs in the modern era now have much more likely probabilities to exceed certain intensification rates in all time windows than in the historical era. Although the 90% confidence interval showed that this data is not statistically significant, Garner calls attention to the slow increase that is seen over time due to warming of the seas. 

    There are five main points that I think the research article is trying to convey: 

1. The mean maximum intensification rates in the modern era are significantly higher than those inthe historical era
2. The rates at which TCs are developing from weak TCs to majro TCs has doubles from the historical era to the modern era
3. The highest percentiles (99.5th) of data for maximum intensification rates is growing way, way faster than the mean which tells us that the extreme storms are getting even more extreme and makes evacuation harder
4. Heat map data shows us that certain areas are being affected more greatly than others, specifcally the southeast coast of the U.S. 
5. The rising sea temperature is also increasing the probability that a TC will be above a certrain intesification rate for all time windows

    I would give Erdenesanaa's article a 5.5/10 solely because it doesn't feel like she is reporting on the article that Garner wrote and is more using it as a citation for her own opinon. She only really talks about the results of point number 2, citing that the probability of a weak TC becoming a major TC has doubled over time. She briefly mentions the heat map data in point 4 but doesn't mention anything about points 1, 3, or 5. She also makes no mention of the fact that Garner specifically says that the data from the intermiediate era to the modern era is not statistically significant which I beleive is an important distinction that should be made. All in all, the news article was only very loosely tied to the scientific article. Because of this, the news article should not be used as a summary of the scientific article or as a means of simplifiying it.