Although the last glass age was much colder than today , with dramatically low sea spirit level , it still included some major shift – one of which has only just been revealed . From 21,900 to 20,500 years ago , ocean levels fell by 20 meters ( 66 feet ) , before recovering much more lento . The discovery not only confirms how big the gap in our noesis are , but that the ice years climate was much more sensitive to modest shift than today .
We know the world was bitterly cold 30,000 - 20,000 class ago , even by ice age standards . Tens of millions of cubic kilometers of water system was locked up in ice sheets in what ’s be intimate as the Last Glacial Maximum . However , it has proven surprisingly difficult to get fine solvent on this . In many locations , the land has shifted with time , either because of tectonic movement or because the weight of nearby ice sheetspushed the footing down . Separating true changes in ocean level from local dry land effect is challenging .
This makes 900 ancient coral samples from two sites off what is now the Great Barrier Reef exceptionally worthful . Even during the coldest time , northerly Australia was n’t glaciated and is very tectonically stable . go steady of corals drilled at these locations has provide an unprecedentedly precise record of Ice Age ocean layer . The answer , issue inNature , admit the breakthrough that over 1,400 years , sea levels fell to around 125 time ( 410 foot ) below current story . They then came back at a rate of 1.6 millimeters ( 0.06 inches ) per yr .
The finding were particularly surprising because more scattered and less reliable data from other locations had led paleoclimatologists to think sea levels were ascend modestly during the period of bang-up fall .
We do n’t yet screw what caused such a striking break , nor the causal agent of apreviously identifiedand even larger drop 31,000 eld ago . Co - authorDr Tezer Esatof the Australian National University described it as “ enigmatic and frustrating ” . He also noted that the previous ice years was marked by unexplained periods of climatic modification get it on asHeinrich events .
Where on the nose all this water went continue a mystery story . “ My gut touch was that it went mostly to Antarctica , " Esat told IFLScience . " But bowel feelings do not look as evidence : It turn out this is not potential . ”
Instead , it seems there was some flesh - up of ice in both Antarctica and North America , with apparently slight modification on what was then the Eurasian Ice Sheet . It ’s not percipient whether the fall ocean levels reflected changes in global mediocre temperature or a shimmy in winds driving moist air over the ice sheet where it fall as snowfall .
Inevitably , non - scientist ' responses to this discovery will let in claim that , if such wild swings can happen naturally , current increases in temperature and ocean level are n’t human induced and are nothing to concern about anyway . A ready check proves how wrong this is . Already sea levels are rising double as fast as this new discovered crepuscule , and this is expect to speed up dramatically . Even the fastest natural climate change are wearisome equate to what humans are causing .
Esat confirm to IFLScience that the findings are a sign : “ mood sensitivity was heightened during the chalk age as oppose to during an interglacial , ” so it took smaller shift in atmospheric conditions to produce basal change to the planet .
If industrial - scale burning of fossil fuels had happened at a prison term when the world was still in an ice age , the effects on global clime would have been much swifter , allow hoi polloi and other living thing even less time to conform to the sudden changes .
