(E) Romania (Steregoiu), mean annual temperature of the coldest month. Every abrupt cooling from the Bray cycle would constitute a tipping point in the gradual insolation changes and the world would settle to a different climatic state after recovering.
(F) Gaussian smoothed (200 yr) GISP2 potassium (non-sea salt) ion proxy for the Siberian High pressure system. We have just started a sixth period with the proposed name of Anthropocene, that should last around 2,200 years, until about 4,200 C. Every one of the last five periods (since 10.2 kyr ago) started with global warming as a recovery from the depressed temperatures of the cooling oscillations that separate the periods. Major periods of the Holocene set by obliquity and a ~2400 year Bray cycle. Blue boxes, major periods of regional and global glacier advances as in Mayewski et al., 2004 and references within.
Due to the contemporary change of climate regime and global temperatures, some regions became cooler and drier, while others became cooler and wetter, leading to a rapid global glacier advance that buried organic remains, like the Quelccaya Glacier plant (, Peru), the South-Cascade Glacier rooted tree-trunk (Washington State) and the Ötztal Alps ice-man, that have remained continuously frozen until the present global warming (Thompson et al., 2006). Evidence for an abrupt global cold and arid event at 5.2 kyr BP. Coincident with the abrupt cooling and hydrological changes of ~ 5,200 yr BP, archaeological studies support a general pattern of abandoned Neolithic human settlements in several areas, including the Andes and the entire Eastern Mediterranean, indicating a widespread climatic crisis that marks the transition from the Chalcolithic to the early Bronze Age (Weninger et al., 2009).
High and low latitude locations of proxy evidence for abrupt climate change ~ 5,200 yr ago. Holocene climate variability The Last Glacial Maximum and the HCO constitute two extreme metastable states, separated by only 10,000 years, that correspond to essentially the same amount of incoming energy from the Sun.
The Neoglacial period is characterized by generalized glacier advances that take place coinciding with the decrease in Northern Hemisphere solar forcing. Cooling events during the HCO, like the 8.2 kyr event, were followed by a complete recovery of temperatures and globally glaciers reached their minimum Holocene extent in most areas between 6000-5500 years BP.
For a geographical representation of the glaciers included in each area see Solomina et al., 2015, figure 1.
Glacier growth was caused by orbital-driven insolation changes.
Although variability in local conditions caused the Neoglacial to start at different times in different glaciological areas, it is generally agreed that it started between 6000-5000 years BP in both hemispheres.
Bond events In addition to the major cooling events of the Bray cycle, other cooling events have taken place during the Holocene, and they have been seen in numerous proxies, but particularly in the Bond series of events.
The amount of detrital petrological tracers transported by icebergs and deposited in the ice-rafted debris belt (an Atlantic region between 40-50° N) greatly increases during episodes of southward and eastward advection of cold surface waters and drift ice from the Nordic and Labrador seas (Bond et al., 2001; figure 48 A).