During the Eocene era , Antarctica featured high denseness of atmospheric CO2 and a subsequent greenhouse clime . By using a new mensuration technique , scientists from Yale University have now watch that south-polar seawaters were once as fond as as those show in Florida and California today .
Top image : Antarctic - Australasian dinosaur of the Cretaceous , a affectionate era that preceded the Eocene . recognition : John Sibbick(used with license ) .
Today , Antarctica is consistently one of the coldest places on Earth , featuring yearly average land temperatures far below zero level Fahrenheit . But it was n’t always that way . Fossilized evidence — including the cadaver of mighty sauropod — show that plant and animals inhabited the region many million of years ago . The continent rest warm even after the extinction of the dinosaur , an earned run average known as the Eocene ( 40 - 50 million age ago ) . And remarkably , woodland were still there as early as 12 million geezerhood ago .
look to study more about the clime during the Eocene era ( about 15 million old age after the dinosaur went extinct ) , Yale geoscientists Hagit Affek , Peter Douglas , Mark Pagani , and colleagues used a new technique promise carbonate clumped isotope thermometry to get a better sense of what south-polar temperature were like back then .
Better Measuring Through Organic Geochemistry
The scientists measured density of rare isotope found in ancient fossil shell taken from East Tasman Plateau and Seymour Island , near the Antarctic Peninsula . Specifically , they measure the teemingness of two isotope bound to each other in fossil bivalve shell . The precise compactness of bond certificate between carbon-13 and oxygen-18 can tell the researchers the temperature in which the shells grew .
Their analysis record that temperature in parts of Antarctica reached as high as 17 degrees Celsius ( 63F ) during the Eocene , and an average of 14 academic degree ampere-second ( 57F ) . This is like to the intermediate one-year temperature off the coast of California today .
In the southerly Pacific Ocean sphere , water temperature reached about 22 degrees C ( 72F ) , exchangeable to seawater temperatures near Florida today . These same H2O now experience an one-year intermediate temperature of about 0 degrees C.
But because these ancient sea temperature were not equally distributed throughout the Antarctic ocean ( they were higher in the south Pacific side ) , the researcher say it likely had to do with the effect of sea currents .
Vulnerable At The Poles
Disturbingly , these finding show that the Earth ’s poles are more vulnerable to clime change than we thought .
“ By measuring past temperature in dissimilar parts of Antarctica , this study gives us a percipient perspective of just how fond Antarctica was when the Earth ’s atmosphere contained much more CO2 than it does today , ” take note Douglas in a affirmation . “ We now know that it was warm across the continent , but also that some part were substantially warmer than others . This provides strong evidence that global heating is especially say close to the Earth ’s poles . Warming in these regions has pregnant issue for clime well beyond the in high spirits latitude due to ocean circulation and melting of polar deoxyephedrine that leads to ocean level rise . ”
Indeed , the simulations showed that pelagic hotness transport in the South Pacific was largely creditworthy for the observed spike in temperature .
interpret the entire subject at PNAS : “ enunciate zonary heterogeneity in Eocene southerly eminent - parallel of latitude sea surface temperatures . ” Supplemental information viaYale University .
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