An ice core regain from theAntarctichas been dated to approximately five million years ago , reserve researchers to study Earth ’s ancient atmosphere . Describing the sample in the journalThe Cryosphere , the work authors explain that the ice dates back to the Pliocene epoch , when globular temperature and carbon dioxide levels were eminent than they are today .
Analyzing Earth ’s climatic weather condition in the aloof past allows scientists to make informedpredictionsabout how the surround is likely to switch in the time to come . For this grounds , investigator regularly attract cores from the ice sheets in easterly Antarctica , hop-skip to find aviation bubbles that have been trapped in the ice for 1000000 of year .
However , the written report authors excuse that “ the oldest glass that has been recovered from the thickest parts of the Antarctic shabu sheets is 800 000 years old . ”
“ The lack of shabu older than [ one million years old ] severely limits our direct paleoclimate record and make uncertainties when posture succeeding climate predictions which admit modeled configuration of the preceding Antarctica Ice Sheet , ” they say .
scientist are particularly acute to obtain ice samples dating back to the Pliocene , which is seen as an analog for currentanthropogenic warming . In search of a sample from this period , the researcher decided to exercise in the Ong Valley , located in the Transantarctic mountains and carry ice believe to be older than eastern Antarctica’sice sheet of paper .
After retrieving a “ rubble - copious icing core ” measure out 944 centimeters ( 371 inches ) in length , the squad analyzed cosmogenic nuclide concentrations in the bouldered detritus to determine the age of the sample distribution . cosmogonical nuclides are rarefied isotope produced by cosmic rays interacting with airfoil rocks , and can be used to calculate how long textile has been buried .
Results indicated that the ice-skating rink sum contained two disjoined layer , the younger of which was rough 2.95 million years old . Beneath this , an older section of ice rink was dated between 4.3 and 5.1 million years old .
“ The ages reported here coincide with the Pliocene date of reference , ” save the field of study generator .
More specifically , the two layer fit to twoglobal glaciations , one of which come during the early Pliocene ( around 4.8 to 4.9 million old age ago ) while the other take billet in the late Pliocene , some 3.3 million twelvemonth ago .
The latter event was followed by a time period in which global temperature exceeded those of today , which is why scientist are so eager to study the Earth ’s atmosphere from this earned run average . Doing so could provide vital clew as to how rising emissions and temperature are likely to affect the planet in the come years .
A cryptical analytic thinking of the ice core will be needed before any such data can be obtained , although the researcher say their initial findings do at least sustain the timing of the Pliocene ’s two frosty advances .
“ conjointly our results show that the continental Methedrine sheet encourage into Ong Valley repeatedly , and grounds of at least two such advance at 2.95 and 4.3–5.1 [ million years ago ] , ” they write .
