By Isabelle Danforth — Taft School
Although there is little doubt among scientists that global temperatures have been increasing for the past century or so, debate still rages in Washington as to whether the rise is anthropogenic or natural. Some politicians, such as the Republican mayor of Miami, Tómas Regalado, are using the severe weather events to raise awareness about the precarious future of the planet. As Hurricane Irma bore down on Florida, the mayor ominously stated, “If this isn’t climate change, then I don’t know what is” (Drash, 2017). Others, including Scott Pruitt, the administrator of the Environmental Protection Agency (EPA), insist that focus on the cause of the storm is distracting from rescue efforts. In a CNN interview prior to Hurricane Irma, Mr. Pruitt argued that “To have any kind of focus on the cause and effect of the storm versus helping people, or actually facing the effect of the storm, is misplaced” (Friedman, 2017). Pruitt’s comments have been heavily criticized by many news networks (Bartel, 2017). However, there is no consensus even among the most prominent of scientists that climate change directly contributed to the recent super storms that have assaulted the United States.
The National Oceanic and Atmospheric Organization (NOAA) predicted five to nine hurricanes during hurricane season, from June 1 to October 30 (Matuson). A comprehensive report by the Geophysical Fluid Dynamics Laboratory (GFDL) in association with NOAA found that “it is premature to conclude that human activities — and particularly greenhouse gas emissions that contribute to global warming — have already had a detectable impact on Atlantic hurricane or global tropical cyclone activity” (“Global Warming”, 2017).
Moreover, numerous scientific papers examining the impact of climate change and hurricane frequency have yielded inconclusive results. Some papers (Vecchi et al, 2008) show a weak upward trend in hurricane frequency because of greenhouse gas emissions while others based on model simulations indicate a large surge of more than 100% hurricane frequency (“Global Warming”, 2017). However, researchers suspect that this increase will not occur until the latter half of the century (Bender et al., 2010).
Nonetheless, the fact that three massive hurricanes have occurred within the span of a week is frighteningly reminiscent of the doomsday scenarios predicted by climate scientists and environmentalists alike. According to a 2001 report by researchers, since 1995, the environment has become increasingly conducive to hurricane activity due to two factors: the warmer North Atlantic sea surface temperatures causing greater evaporation and the reduced vertical wind shear which prevents the dissipation of hurricanes and contributes to their growth (Goldenberg et al., 2001). Sea surface temperatures appear to have increased since 1950. A scientific review paper in Nature magazine stated that “Sea surface temperatures… have increased by several tenths of a degree Celsius during the past several decades” (Knutson et al., 2010). Additionally, the impact of the superstorms on sea-side communities is exacerbated by the rising sea levels. Since 1993, the waters have risen an average of 2.6 inches, bringing the oceans closer to populations. Thus, severe weather events such as Hurricanes Harvey and Irma are more likely to cause severe flooding and destruction (Drash, 2017).
Ultimately, neither model projections or historic analyses of hurricane trends fully support the idea that anthropogenic climate change has contributed to the significant increase in overall hurricane numbers in the Atlantic Ocean (“Global Warming”, 2017). In the future, however, the increase in sea-surface temperatures may continue to cause greater sea water evaporation which will increase the intensity of the storms that occur (Wright et al., 2015). Although presently the relationship between hurricanes and the changing climate is unclear, “it is likely that greenhouse warming will cause hurricanes in the coming century to be more intense globally and have higher rainfall rates than present day hurricanes” (“Global Warming”). Anthropogenic climate change may cause more severe storms, but the exact nature of these storms has yet to be revealed.
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