The speedy rise of world temperature during the last century is nearly definitely unprecedented in current Earth history; however our present fee of sea stage rise has stiffer competitors. About 14,650 years in the past, because the thawing of the final ice started to hit its stride, the sea stage made an outstanding leap of 12 meters or extra—and did so in lower than 400 years. It is an occasion identified to scientists as Meltwater Pulse 1A.
Determining the place all that water got here hasn’t been straightforward. It was definitely the results of melting glacial ice (and never some form of biblical sky-flood); however, fashions of previous ice sheet change haven’t fairly added up.
A brand new examination led by Jo Brendryen on the University of Bergen takes a fascinating route to find that the melting of the Eurasian Ice Sheet, which has largely been neglected, may simply clarify issues.
Carbon courting works a bit of otherwise from different forms of radiometric courting, in that carbon-14 is consistently produced by reactions in Earth’s ambiance. Something that takes in carbon atoms—which incorporates residing issues—will due to this fact have an analogous quantity because the environment; as soon as it stops that uptake, carbon-14 will progressively decay and switch into nitrogen-14. The older that factor is, the much less carbon-14 will probably be left in it.
One complication is that the manufacturing fee of carbon-14 within the ambiance varies barely over time. As a result of this system can solely be used about 50,000 years or so into the previous; nevertheless, scientists have been in a position to measure issues with recognized ages (like tree rings) to cross-examine and calibrate carbon-14 concentrations to ages.