COPENHAGEN, Denmark, March 15 (UPI) -- A Danish scientist said the idea of a "global temperature" and global warming is more political than scientific.

University of Copenhagen Professor Bjarne Andresen has analyzed the topic in collaboration with Canadian Professors Christopher Essex from the University of Western Ontario and Ross McKitrick of the University of Guelph.

It is generally assumed the Earth's atmosphere and oceans have grown warmer during the recent 50 years because of an upward trend in the so-called global temperature, which is the result of complex calculations and averaging of air temperature measurements taken around the world.

"It is impossible to talk about a single temperature for something as complicated as the climate of Earth," said Andresen, an expert on thermodynamics. "A temperature can be defined only for a homogeneous system. Furthermore, the climate is not governed by a single temperature. Rather, differences of temperatures drive the processes and create the storms, sea currents, thunder, etc. which make up the climate".

He says the currently used method of determining the global temperature -- and any conclusion drawn from it -- is more political than scientific.

The argument is presented in the Journal of Non-Equilibrium Thermodynamics.