As the settled science of climate change tells us, evil human beings are responsible for the historically high global temperatures. Activists appear content to ignore facts such as the warming has stopped, or that it has in fact been hotter is eras prior to the industrial revolution when we began bellowing chemicals into the atmosphere. If it’s true that there were periods of warming as substantial or more so in times prior to modern emissions of greenhouse gas pollutants, it should give us pause when trying to assign human activity to any real or apparent warming happening now*.
(CO2Science.org) — In commenting further on these findings, Kullman says that “the emergence during the past two millennia of at least two short-term tree line and thermal excursions to higher than present levels (i.e. early 21st century) indicates that the current performance of the ecological and climatic systems is well within the envelope of the natural variability of the late Holocene (cf. Karlen, 2008; Akasofu, 2010; Curry and Webster, 2011; Humlum et al., 2011; Kobashi et al., 2011; Ljungqvist et al., 2012).” And to make this point perfectly clear, Kullman repeats that “the pine tree line (and summer temperature) was consistently higher than present … during the Roman and Medieval periods, c. 1900 and 1000 cal years BP.”
Thus, as we have long contended, and on the basis of real-world data (properly analyzed), Kullman’s analysis of tree-line data, along with the results of the many other studies he cites, jointly provide yet another strong amalgamation of evidence that supports the view that there is nothing unusual, unnatural or unprecedented about earth’s current level of warmth.
As records for low temperatures continue to mount at the same time record highs for greenhouse gasses are measured in the atmosphere, climate change activists persistently refuse to acknowledge that it looks more and more likely that increased CO2 levels correlate with higher temperatures, rather than cause them.
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* Requires intellectual honesty.
Sifting Reality 
Any Thoughts?