A Reexamination of Climate Change Issues

No Global Warming Link to Tornado Activity

 November 18, 2009


This article contains excerpts from a NOAA study showing that the warming of the earth’s climate has not effected the strength or intensity of United States tornado activity during the past century.  The study explains that while graphs often give an appearance of increased tornado activity, it is only due to improved levels of monitoring rather than an actual increase in tornadoes.

Following are excerpts from the study, the original article can be found here.  More information about this issue can also be found on the Coyote Blog.


"With increased national doppler radar coverage, increasing population, and greater attention to tornado reporting, there has been an increase in the number of tornado reports over the past several decades.  This can create a misleading appearance of an increasing trend in tornado frequency.  To better understand the true variability and trend in tornado frequency in the US, the total number of strong to violent tornadoes (EF3 to EF5 category on the Enhanced Fujita scale) can be analyzed.  These are the tornadoes that would have likely been reported even during the decades before Dopplar radar use became widespread and practices resulted in increasing tornado reports.  The bar chart below indicates there has been little trend in the frequency of the strongest tornadoes over the past 55 years."