|Erlongwan maar lake.|
A 1000-yr record of environmental change in NE China indicated by diatom assemblages from maar lake Erlongwan
suggests that AD 1150 and 1200 was the warmest over the past 1000 yrs
The ten researchers report that "three intervals were identified by their diatom assemblages and correspond within dating uncertainties to the Medieval Warm Period, the Little Ice Age and the 20th century warming trend." During the MWP, they further indicate that "the duration of the summer was longer while the spring and autumn were shorter than the 20th century." And they unequivocally declare that "the period between ca. AD 1150 and 1200 was the warmest interval of the past 1000 years."
What it means
In view of the fact that, prior to the time of their study, there was no record of mean annual temperatures from NE China covering the past 1000 years with the same resolution as their diatom record, Wang et al.'s work demonstrates - for yet another part of the planet (see our Medieval Warm Period Project) - that late-20th-century warmth, even with the help of an extra 100 ppm of CO2, was less than that of the MWP, which makes it extremely difficult to believe that earth's current level of warmth largely owes its existence to anthropogenic CO2 emissions, as the world's climate alarmists continue to claim it does.