Weather Temperature variations during the Holocene. The Holocene began after the event ended the Younger Dryas cooling, after which the temperatures are milder. The Holocene Climatic Optimum was a warm period that occurred during the interval between approximately 9000 and 5000 years ago. The global climate was between 0.5-2 C warmer than it is today. However, the warming probably was not uniform throughout the world. This period ended around 5500 years ago, when the first human civilizations in Asia and Africa began to flourish. Then began the Neoglacial, where temperatures dropped gradually until the twentieth century, with the possible exception of heating the Medieval Climatic Optimum (siglos X-XIV).The highlight of the cooling was the Little Ice Age, with three maxima: over 1650, 1770 and 1850. The warming of the Holocene has been an interglacial period and there is no reason to believe they represent the view of glacial cycles. However, current global warming may cause the Earth to warm more than the previous interglacial period, Riss-W rm, which peaked at approximately 125,000 years ago temperatures warmer than today. This phenomenon is sometimes called a super-interglacial. Compared to glacial conditions in the habitable zones interglacial spread northward, reaching its northernmost point during the Holocene Climatic Optimum. Increased moisture in the polar regions caused the disappearance of boreal grasslands.