The sentence, first of all, perpetuates two well-known fallacies regarding the so-called "Medieval Warm Period" and "Little Ice Age". See the RealClimate discussions of the Little Ice Age and Medieval Warm Period for explanations of why both the Viking colonization of Greenland and the freezing of the River Thames actually tells us relatively little about past climate change.
The actual large-scale climate changes during these intervals were complicated, and not easily summarized by simple labels and cherry-picked anecdotes. Climate changes in past centuries were significant in some parts of the world, but they were often opposite (e.g. warm vs. cold) in different regions at any given time, in sharp contrast with the global synchrony of 20th century warming.
You keep reprinting this info. But every time I check, there are plenty of perfectly sober scientific articles referencing studies in the Sargasso Sea or New Zealand, which say that the Medieval Warm Period was global.
Like this:
Science 23 February 2001:
Vol. 291. no. 5508, pp. 1497 - 1499
DOI: 10.1126/science.291.5508.1497
Prev | Table of Contents | Next
Perspectives
PALEOCLIMATE:
Was the Medieval Warm Period Global?
Wallace S. Broecker
During the Medieval Warm Period (800 to 1200 A.D.), the Vikings colonized Greenland. In his Perspective, Broecker discusses whether this warm period was global or regional in extent. He argues that it is the last in a long series of climate fluctuations in the North Atlantic, that it was likely global, and that the present warming should be attributed in part to such an oscillation, upon which the warming due to greenhouse gases is superimposed.
sciencemag.org
I might add that these studies also deny the perfect synchronicity of warming claimed in your paper. They also point out the variability and complexity of climate, and the uncertainty of the models available. |
