A New Record of Late Holocene Climate at the Antarctic Peninsula
Lu, Z., Rickaby, R.E.M., Kennedy, H., Kennedy, P., Pancost, R.D., Shaw, S., Lennie, A., Wellner, J. and Anderson, J.B. 2012. An ikaite record of late Holocene climate at the Antarctic Peninsula. Earth and Planetary Science Letters 325-326: 108-115.
Explaining that ikaite "is a low temperature polymorph of calcium carbonate that is hydrated with water molecules contained in its crystal lattice," Lu et al. write that "ikaite crystals from marine sediments, if collected and maintained at low temperatures, preserve hydration waters and their intact crystal structures, both of which have the potential to provide isotopic constraints on past climate change," after which they go on to describe "the first downcore δ18O record of natural ikaite hydration waters and crystals collected from the Antarctic Peninsula (AP)" that they say were "suitable for reconstructing a low resolution ikaite record of the last 2000 years."
In doing so, the nine UK and US researchers report that "the ikaite record qualitatively supports that both the Medieval Warm Period and Little Ice Age extended to the Antarctic Peninsula." They also state that the "most recent crystals suggest a warming relative to the LIA in the last century, possibly as part of the regional recent rapid warming," but they add that "this climatic signature is not yet as extreme in nature as the MWP," suggesting that even the dramatic recent warming of the AP may not yet have returned that region to the degree of warmth that was experienced there during the MWP, when the atmosphere's CO2 concentration was more than 100 ppm less than it is today.
Such new evidence adds to the already voluminous database that suggests that the Earth has not yet eclipsed the level of global warmth experienced during the MWP, even with the help of all of the anthropogenic-produced CO2 that resides in the atmosphere, which facts cast great doubt upon the climate-alarmist claim that anthropogenic CO2 is the primary cause of Earth's current level of not-so-unprecedented global warmth.