Monday, April 21, 2014

Review paper finds the Medieval Warm Period was global and its peak warmth likely significantly greater than the present

A new paper from SPPI and CO2 Science reviews the scientific literature on the Medieval Warm Period in Upper North America, and concludes, "these published results now join the many other similar results, from all around the world, where it can be seen that the Medieval Warm Period was not only a global phenomenon, but that its peak warmth was very likely significantly greater than that of the Current Warm Period."

[Illustrations, footnotes and references available in PDF version]

Climate alarmists claim that rising atmospheric CO2 concentrations due to the burning of fossil fuels, such as coal, gas and oil, have raised global air temperatures to their highest level in the past one to two millennia. And, therefore, investigating the possibility of a period of equal global warmth within the past one to two thousand years has become a high-priority enterprise; for if such a period could be shown to have existed, when the atmosphere's CO2 concentration was far less than it is today, there would be no compelling reason to attribute the warmth of our day to the CO2 released to the air by mankind since the beginning of the Industrial Revolution. Thus, in this review of the pertinent scientific literature, results of the search for such knowledge are presented for studies conducted within the borders of Canada and other regions north of the lower 48 states of the United States of America.
There is nothing unusual or unnatural about climate change. It happens on decadal scales, centennial scales and millennial scales. And over the past century or two, the earth has experienced a natural and not-unexpected millennial-scale climatic shift that may or may not have yet run its course.
The fact that the air's CO2 content increased in phase with this shift is simply due to the coincidental concurrent development of the Industrial Revolution and its subsequent transformative impact on humanity.
Since the peak warmth of the Medieval Warm Period was caused by something quite apart from elevated levels of atmospheric CO2, or any other greenhouse gas for that matter, there is no reason to not believe that a return engagement of that same factor or group of factors is responsible for the even lesser “peak” warmth of today.

But if not CO2, then what? According to Luckman and Wilson, some solar-related phenomenon may well be the main driver of the low frequency temperature trends.

The same story is also told by tree ring-width anomalies from the adjacent Wrangell Mountains of Alaska. Hence, it can be concluded from two different data bases that the region's current temperature is, in fact, lower than it was during the warmest part of the Medieval Warm Period, adding more weight to the growing mountain of evidence that indicates there is nothing unusual about the planet's current level of warmth.

These results now join the many other similar results, from all around the world, which have been archived in the databases of's Medieval Warm Period Project29, where it can be seen that the Medieval Warm Period was not only a global phenomenon, but that its peak warmth was very likely significantly greater than that of the Current Warm Period.


  1. What is amazing to me is those alarmists who are still claiming that there is no other explanation for our current (such as it is) warming !

  2. It simply had to be warmer. During the height of that period, Greenland was GREEN. Viking settlers lived there for something like 300 years and kept cattle, etc- the same diet they used 'back home'. National Geographic reported that these folks actually died out because the climate cooled again and they refused to adapt to the inuet(?) diet. Sorry folks, its been years since I read about this, but I have noticed that Greenland still ...isnt green.

    1. "The Norse arrived in Greenland 1,000 years ago and became very well established," says Schweger, describing the Viking farms and settlements that crowded the southeast and southwest coasts of Greenland for almost 400 years.
      "The Greenland settlements were the most distant of all European medieval sites in the world," said Schweger. "Then the Norse disappear, and the question has always been: what happened?"

      Cross-sections of the GUS soil show the Vikings began their settlement by burning off Birch brush to form a meadow. Over the next 300 to 400 years, the meadow soil steadily improved its nutritional qualities, showing that the Greenland Vikings weren't poor farmers, as McGovern and others have suggested. "At GUS, the amount of organic matter and the quality of soil increased and sustained farming for 400 years," says Schweger. "If they were poor farmers, then virtually all the farming in North America is poor farming."

  3. I will throw this out there. The left hates the Medieval warm period because Marx did not come from it, the French "enlightenment" did not come from it, and the umbrella of leftism did not come from it. Instead, great cathedrals came from it, the formation of the middle class came from it, and Christian universities came from it. Maybe the left wants a redux of the famines and religious wars that followed the onset of the little ice age. That would explain why they have so much contempt for Christians.