By Marco Gamez
1. Worst Drought
According to the National Weather Service, in 2011 Texas endured the single worst drought in it's history. During the drought, which began in October 2010, wildfires burned thousands of square miles and may have killed as much as half a billion trees (Tam 1). The weather was hot and dry with very little rain throughout the year. August 2010 through July 2011 saw the brunt of the worst drought with abnormally low rainfall. Many ranchers had to cull their cattle and many farmers suffered record low yields in crops. The rains were so few that rivers dried, lake levels dropped by incredible degrees, and the economy of Texas took a huge hit to the tune of billions of dollars. 2. Causes
So what caused such a drought in the southern US? The answer is not simple and there are many factors involved when trying to discern the facts from the all the possible culprits. Dr John Nielsen-Gammon, the State Climatologist who is also a professor of at Texas A&M University where he teaches atmospheric sciences points the finger to three patterns that are largely responsible for the 2011 drought. The Atlantic Multidecadal Oscillation, a temperature variation that became warm during the mid 1990's. The Pacific Decadal Oscillation, a similar pattern which began cooling Pacific in the tropics during 2009, and The El Niño/La Niña Southern Oscillation. In mid 2010, La Niña developed from the previous weather pattern of El Niño.
Dr. Nielsen-Gammon stated that the 1950's and early 60's was the last time the weather patterns aligned causing a drought that lasted almost 10 years (Combs 3). 3. Blame it on La Niña
During a time when the east coast has had a flood of rain, Texas has been suffocating under a drought not seen in at least a hundred years. According to an article on New Scientist, the drought and the high temperatures were caused by the “lingering effects” from the La Niña ENSO that occurred from the summer of 2010 to the spring of 2011. The La Niñas have caused precipitation to bypass Texas by traveling across the northern states(New Scientist 4).
In the text book Physical Geography: A Landscape Appreciation, La Niña is described as having the opposite effects of El Niño and being “an episodic atmospheric and oceanic phenomenon of the equatorial Pacific Ocean, particularly prominent along the west coast of South America” but which has global impact including “the southwestern United States is drier than usual while Southeast Asia and northern Australia are wetter” (Stadler 131). The book goes on to state that the causes and effects of the weather oscillations are not fully understood. While a strong El Niño might bring rain to Texas, a weak or moderate El Niño might cause either strong rains or drought effects. The book also states that there is a possibility that global warming may be having an effect on the intensity of the oscillation but that there is no clear evidence to make a connection as of yet (Stadler 136). 4. Human Effects
Janet Raloff in online science magazine Science News makes the argument that the recent intense weather may have its roots in a climate affected by humans (Raloff 14). She cites a report written by David Rupp for the Bulletin of American Meteorological Society on behalf of Oregon State University that Texas' chances of experiencing extremes in hot and dry weather during an event of La Niña have increased twenty-fold since the 1960's and caused by global warming, an effect produced by humans. Rupp goes on to say in the same report that “most of the large-scale warming that has occurred over the past 50 years is thought to be attributable to the anthropogenic increase in greenhouse gas levels” assisting in identifying the culpable agents leading to the 2011 event. Rupp concludes by stating that the conditions leading to the event of 2011 are much more likely to reoccur than 40 or 50...