Close this search box. thinks ‘global warming’ is increasing ticks in Alabama, except it’s cooled over the last century there

By Anthony Watts

From the “you really should check the data before you invoke the universal boogeyman” department:

‘Very bad tick year’ expected for Alabama in 2017, and climate change a factor

2017 could be a record year for ticks and tick-borne illnesses according to one researcher who studies the arachnids in Alabama. “I would say this is going to be a very bad tick year because it was a very mild winter,” said Tim Sellati, chair of Southern Research’s Infectious Diseases Department.

In addition, Sellati said a warming climate has let certain species of ticks expand their range and those changes are reflected in tick surveys in Alabama and other parts of the United States. “The winters are warmer and the ticks recognize this, they sense this change in their environment,”


Uh, no. It has not warmed in Alabama in the last century according to NOAA’s own data. In fact the average temperature has COOLED since 1895:

The minimum temperature trend essentially flat:

And if “ticks recognize this, they sense this change in their environment,” according to Tim Sellati, chair of Southern Research’s Infectious Diseases Department, you’d think they would sense that Alabama is getting cooler, especially the daytime high temperatures:
Here’s the problem:
Tim Sellati is conflating weather with climate. Weather patterns typically span days to weeks, while climate is defined as a 30 year interval according to the World Meteorological Organization (WMO):

Climate, sometimes understood as the “average weather,” is defined as the measurement of the mean and variability of relevant quantities of certain variables (such as temperature, precipitation or wind) over a period of time, ranging from months to thousands or millions of years.

The classical period is 30 years, as defined by the World Meteorological Organization (WMO).  Climate in a wider sense is the state, including a statistical description, of the climate system.

And here’s where Sellati goes really really wrong, note the single end data point, December through February, the “winter” months for Alabama, there’s a nice warm spike there, though not as warm as the spike of 1932. There’s also an ever so slight, though statistically insignificant warming trend since 1895. Note in the legend, NOAA reports that as 0.0F per decade: