Advocates of catastrophic man-made global climate change have been exploiting the recent flooding disaster that was Hurricane Harvey and the landfall of Irma to advance their notion of linkage between global warming and these tragedies. The theory behind the connection between warming and hurricane activity is superficially plausible: global warming raises ocean surface temperatures, fueling tropical cyclones and hurricanes. That seems to be a perfectly reasonable prediction. The facts say otherwise.
Inconveniently for the promoters of this belief that the warming we have seen over the last 150 or so years increases the frequency and intensity of hurricanes, the actual data strongly disavow that idea. Both the long-term data going back hundreds of years and the shorter length data for the last several decades reveal that there has been no increase in frequency of tropical storms or hurricanes. In fact, a strong case can, and has been advanced, that hurricane frequency has been in slight decline despite warming temperatures and increasing CO2.
The evidence is so compelling that nearly all competent climate researchers, including man-made global warming’s biggest advocate, the Intergovernmental Panel on Climate Change (IPCC) agree that there is no evidence supporting linkage between these storm events and warming. The IPCC in both its 2012 Special Report on Extreme Weather and its 2013 Fifth Assessment Report concluded that there was a lack of evidence to support these claims.
NOAA (2016) provides a good record of the number of hurricanes in the North Atlantic dating to 1880 including the total hurricanes (adjusted) and those that made landfall in the United States (Figure 1). Both records show a clear decrease in hurricanes over the last 140 years, not the increase as claimed by some climate alarmists.
To provide “scientific” evidence of increasing hurricanes, some global warming advocates have stooped to using the unadjusted number of hurricanes which shows a clear uptrend that they have contended is due to global warming. This unadjusted number is completely attributable to better coverage provided by satellites, as prior to satellite coverage, many hurricanes formed but were never recorded unless they made landfall. A recent study from the Geophysical Fluid Dynamics Laboratory concluded “it is likely that the increase in Atlantic tropical storm and hurricane frequency in HURDAT since the late-1800s is primarily due to improved monitoring.”
As further confirmation that there is no upward trend in hurricane frequency, intensity or duration, in 2016 Rojo-Garibaldi and his team at the National University of Mexico reviewed data going back to 1749 and found that “from 1749 to 2012 the linear trend in the number of hurricanes is decreasing.”
So what are global-warming alarmists to do when they just can’t get the data to cooperate with their preconceived notions? The answer is to fund more studies. In this case, researchers from Florida State conducted a study that used complex climate models (which fail miserably in actual predictions) to predict that hurricanes will become fewer but more intense. Climate Therrmageddon proponents have latched onto this idea of “fewer but bigger” storms to continue to promote a state of fear.
Christopher Landsea, a meteorologist for the National Hurricane Center, has quantified what a global-warming driven increase in the intensity of major hurricanes may mean. His work indicates that the warming over that last several decades translates into an increase in intensity of about 1%. For a Category 5 hurricane like Katrina, the wind speed would increase by 1 to 2 mph. He wrote: “The 1-2 mph change currently in the peak winds of strong hurricane due to manmade global warming is so tiny that it is not measureable by our aircraft and satellite technologies available today, which are only accurate to about 10 mph (~15 kph) for major hurricanes.
To further support the idea that hurricanes are not becoming stronger and bigger, the landfall of Hurricane Harvey last week marked the first occurrence of a major hurricane (Category 3 or above) to strike the United States in nearly 12 years. That is more than 4,300 days without America suffering the devastation that these large storms bring. That is also a record length of time that the United States has gone without a landfalling major hurricane. The second longest streak was a period of eight years from 1861 to 1868.
Rest easy and be assured that, no matter what happens with the remainder of the 2017 hurricane season, you will not be to blame, it will be Mother Nature unleashing her fury just as she has for many millions of years.
IPCC (2013) Climate change 2013: The Physical Science Basis. Contribution of Working Group I to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change [Stocker TF, Qin D, Plattner GK et al (eds)]. Cambridge University Press, Cambridge, United Kingdom & New York, NY, USA, 1535 pp.
Landsea C (2011) Hurricanes and Global Warming. Opinion piece on NOAA website: http://www.aoml.noaa.gov/hrd/Landsea/gw_hurricanes/
NOAA (National Oceanic and Atmospheric Administration). 2016. The Atlantic Hurricane Database Re-analysis Project. www.aoml.noaa.gov/hrd/hurdat/comparison_table.html.
Rojo-Garibaldi B, Salas-d-Leon DA, Sánchez NL, Monreal-Gómez MA (2016) Hurricanes in the Gulf of Mexico and the Caribbean Sea and their relationship with sunspots Journal of Atmospheric and Solar-Terrestrial Physics 148 · October 2016 DOI: 10.1016/j.jastp.2016.08.007
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