The Medieval Warm Period and the Little Ice Age Were Worldwide

The catastrophic anthropogenic global warming alarmists have consistently downplayed both the Medieval Warm Period and the Little Ice Age.  They have tried to reduce the warmth of the former and reduce the coldness of the latter.  They have claimed that these events were limited to Europe or to the Northern Hemisphere.  There has actually been a plethora of evidence that these were worldwide events as is discussed in Ian Plimer's book Heaven and Earth, but most of the evidence was obtained in the Northern Hemisphere as discussed in my earlier post.  A very interesting new study has shown that both events took place in the Antarctic Peninsula as well.

Zunli Lu of Syracuse University and a host of colleagues from Oxford University, Bangor University, the University of Bristol, the University of Leeds, the Diamond Light Source, Houston University, and Rice University have published An ikaite record of late Holocene climate at the Antarctic Peninsula in Earth and Planetary Science Letters.  Ikaite crystals are a form of calcium carbonate or limestone and only form under cold conditions.  They melt at room temperature.  The oxygen isotope concentration in the crystals can be measured and provides a history of the temperature when the crystals were formed.  Lu and his colleagues were able to find and date ikaite crystals from the Antarctic Peninsula and construct the temperature record.  They found that both the Medieval Warm Period and the Little Ice Age occurred in the Antarctic.

This is important because it says that the recent worldwide warming is not unprecedented and it is not necessary to believe that only man's emissions of carbon dioxide can explain that unprecedented warming.  Atmospheric carbon dioxide concentrations were not as high at the time of the Medieval Warm Period and are not needed to explain it.  In addition, the Little Ice Age ended as the Industrial Revolution got into gear.  The increase of carbon dioxide since then is at least substantially due to the worldwide warming of the oceans, which have immense quantities of dissolved carbon dioxide and solid carbonates in them.  It is known that the warming ocean waters evolve carbon dioxide and those waters have certainly been warming since the end of the Little Ice Age.  It is a matter of major consequence therefor that both the Medieval Warm Period and the Little Ice Age appear to have been worldwide events.