Ross McKitrick made the same argument over a decade ago: Why Should We Trust A Statistic That Might Not Even Exist?

“Discussions on global warming often refer to ‘global temperature.’ Yet the concept is thermodynamically as well as mathematically an impossibility,” says Science Daily, paraphrasing Bjarne Andresen, a professor at the University of Copenhagen’s Niels Bohr Institute, one of three authors of a paper questioning the “validity of a ‘global temperature.’”
 

“The temperature obtained by collecting measurements of air temperatures at a large number of measuring stations around the globe, weighing them according to the area they represent, and then calculating the yearly average according to the usual method of adding all values and dividing by the number of points.”
 
But a “temperature can be defined only for a homogeneous system,” says Andresen. The climate is not regulated by a single temperature. Instead, “differences of temperatures drive the processes and create the storms, sea currents, thunder, etc. which make up the climate”.

A new study;

… has found winters in northern China have been warming since 4,000BC – regardless of human activity – but the mainland scientists behind the research warn there is no room for complacency or inaction on climate change, with the prospect of a sudden global cooling also posing a danger.
 
The study found that winds from Arctic Siberia have been growing weaker, the conifer tree line has been retreating north, and there has been a steady rise in biodiversity in a general warming trend that continues today. It appears to have little to do with the increase in greenhouse gases which began with the industrial revolution, according to the researchers.
 

Lead scientist Dr Wu Jing, from the Key Laboratory of Cenozoic Geology and Environment at the Institute of Geology and Geophysics, part of the Chinese Academy of Sciences, said the study had found no evidence of human influence on northern China’s warming winters.