Followingthe end of the Eemian, a large number of other sudden
changes and short-livedwarm and cold events have been documented.
These are most prominent in theice-core record of Greenland and the pollen records of Europe, suggesting thatthey were most intense in the North Atlantic region.It is not yet clear if the general pattern of the transitionbetween the Younger Dryas and Holocene is representative of other rapid warmingand cooling events in the past 110,000 years. It marks the end of the HighPaleolithic . Othersudden
climate transitions since the start of the Holocene: Followingthe sudden start of the Holocene about 11,000 years ago, there have been anumber of sudden, widespread climate
changes recorded from the palaeoclimaticrecord around the world. This new population was proto-Indo-European, andlikely brought into Europe the beginnings of the Neolithic, agricultural,culture, which had arisen in the Middle East in response to climate stress.The effects of the Little Ice Age are well-documented in the recenthistorical record, although climatic change has rarely been considered as asignificant factor in History.TheNorth Atlantic has a peculiar circulation pattern; the north-east trending GulfStream carries warm and relatively salty surface water from the Gulf of Mexicoup to the seas between Greenland, Iceland and Norway. Upon reaching there, thesurface water cools off and (becomes dense enough to sink into the deep ocean. The Arcticice began to melt. During glacial phases, the trigger for a shut-off was thesudden emptying into the northern seas of a lake formed along the edge of alarge ice sheet on land (for instance, the very large ice-dammed lake thatexisted in western Siberia), or a diversion of a meltwater stream into the pathof the Gulf Stream (as seems to have occurred as part of the trigger for theYounger Dryas cold event). The result could be a very sudden climate change tocolder conditions, as has happened many times in the area around the NorthAtlantic during the last 100,000 years.Thispresents the apparent paradox that global warming could actually create much colderclimate in certain parts of the world. Clearly, the "gradualist"models of warming over the next few centuries - as publicized by the energycompanies - could be very far off the mark. Americans would no longer need tomove to the Sun Belt, rather the Sun Belt would move to them. The sudden switchcould also occur in the opposite direction, for example if warmer summerscaused the sea ice to melt back to a critical point where the sea ice lidvanished and the Gulf Stream was able to start up again. Indeed, following aninitial cooling event the evaporation of water vapor in the tropical Atlanticcould result in an 'oscillator' whereby the salinity of Atlantic Ocean surfacewater (unable to sink into the north Atlantic because of the lid of sea ice)built up to a point where strong sinking began to occur anyway at the edges ofthe sea ice zone. The onset of sinking could result in a renewed northward fluxof warm water and air to the north Atlantic, giving a sudden switch to warmerclimates, as is observed many times within the record of the last 130,000 yearsor so.Antarcticawould be even colder than it is now, because much of the heat that it doesreceive ultimately comes from Gulf Stream water that sinks in the northAtlantic, travels in a sort of river down the western side of the deep AtlanticBasin and then resurfaces just off the bays of the Antarctic coastline. Thereis actually evidence from the study of ocean sediments that deepwater formationin the north Atlantic was diminished during the sudden cold Heinrich events andother colder phases of the last 130,000 years, and that the process 'switchedon' rapidly at times when climates suddenly warmed around the north AtlanticBasin. Instead, during the most intense cold phases the deepwater formationarea seems to have moved to the south of the British Isles, at the edge of theextended sea ice zone. This was pbly because the whole surface of theAtlantic Ocean (even the tropics) was cooler; with less evaporation from itssurface, even the water that did reach northwards was less briny (and thus lessdense), so less able to sink when it reached the cold edge of the sea ice zone.By extrapolation, it is generally thought that bigger changes in the northAtlantic circulation would result in correspondingly larger changes in climatesin the monsoon belts and in other parts of the world.Largervascular plants and mosses might have the same effect on the timescale of yearsor decades. The recent detailed analysis of the ending of the Younger Dryas byTaylor et al. The drier and colder the world gets, the more desert there is andthe higher the wind speeds, sending more desert dust into the atmosphere whereit reinforces the cold and dryness. Conversely, a run of wet years in themonsoon belt could trigger revegetation of desert surfaces and a suddendecrease in the amount of dust blown into the atmosphere. The various largefull-interglacial climate changes during the Holocene and certain earlierinterglacials (e.g. the Eeemian and the Holstein Interglacials in Europe) thatshow up in the Greenland ice cap do seem to correlate with genuinely largeclimate shifts in Europe and elsewhere, taking conditions from temperate toboreal or even sub-arctic. This was the case with the rise of mammals, afterthe end-Cretaceous extinction of the dinosaurs. Asmall-scale example of man’s inability to adjust to climate change can be seenin the steady desertification of much of the Sahel in Africa, where the Saharahas been advancing.