The global temperature records show the fluctuation of temperature from ocean to landraces and varying extremes. These have existed since the 1850 period when measured from the Pleistocene ice age by the use of various tools and techniques like the weather balloon radioscopy.
Tree ring and ice core data have shown a measuring record from 1000 to 2000 years of data, based on lake sediments, cave deposits and fossils records. The global mean surface temperatures have ranged for over 25 years of span with periods of little ice age and medieval warm periods.
I have not read about the said article but maybe this can be of help. One of the biggest challenge for the unification of North and South Korea would be the incompatibility of governments between the North and South. The two are polar opposites. Hope this helps. Have a nice day.