One of the biggest stumbling blocks to the climate campaign has been the well-established existence of the Medieval Warm Period (MWP), when temperatures were as warm or warmer than today, but when there were no SUVs to blame it on. The obvious implication is that if it was as warm then as it is today, you can’t rule out—in fact you should probably rule in—that natural causes partly or wholly explain the warming of the last century. The climateers tried to make it go away with the hockey stick, but as the two tranches of leaked/hacked emails showed, even the scientists in the inner circle of the climate campaign thought this was weak or incorrect.
But the main fallback position of the climate campaign has always been that the warmth of the medieval warm period was a localized phenomenon—localized to northern Europe. We lacked evidence from the southern hemisphere to prove that the MWP was a global phenomenon.
Well now we do have some evidence that the MWP was global, courtesy of new research from Syracuse University, and forthcoming in Earth and Planetary Science Letters. From the Syracuse press release:
The scientists studied ikaite crystals from sediment cores drilled off the coast of Antarctica. The sediment layers were deposited over 2,000 years. The scientists were particularly interested in crystals found in layers deposited during the “Little Ice Age,” approximately 300 to 500 years ago, and during the “Medieval Warm Period,” approximately 500 to 1,000 years ago. Both climate events have been documented in Northern Europe, but studies have been inconclusive as to whether the conditions in Northern Europe extended to Antarctica. . .
“We showed that the Northern European climate events influenced climate conditions in Antarctica,” Lu says. “More importantly, we are extremely happy to figure out how to get a climate signal out of this peculiar mineral. A new proxy is always welcome when studying past climate changes.”
But how inconvenient for the climateers. They’ll have to think of a new talking point to make the MWP insignificant. (Hap tip to the NY Times’ Andy Revkin, who flagged this on Twitter this morning. He’s one mainstream reporter who shoots straight on this issue.)