Snapshot of past climate reveals no ice in Antarctica millions of years agoJuly 29, 2008A snapshot of New Zealand's climate 40 million years ago reveals a greenhouse Earth, with warmer seas and little or no ice in Antarctica, according to research published this week in the journal Geology A snapshot of New Zealand's climate 40 million years ago reveals a greenhouse Earth, with warmer seas and little or no ice in Antarctica, according to research published this week in the journal Geology. The study suggests that Antarctica at that time was yet to develop extensive ice sheets. Back then, New Zealand was about 1100 km further south, at the same latitude as the southern tip of South America - so was closer to Antarctica - but the researchers found that the water temperature was 23-25°C at the sea surface and 11-13°C at the bottom. "This is too warm to be the Antarctic water we know today," said Dr Catherine (Cat) Burgess from Cardiff University's School of Earth and Ocean Sciences, and lead-author of the paper. "And the seawater chemistry shows there was little or no ice on the planet." These new insights come from the chemical analysis of exceptionally well preserved fossils of marine micro-organisms called foraminifers, discovered in marine rocks from New Zealand. The researchers tested the calcium carbonate shells from these fossils, which were found in 40 million-year-old sediments on a cliff face at Hampden Beach, South Island. "Because the fossils are so well preserved, they provide more accurate temperature records." added Dr Burgess. "Our findings demonstrate that the water temperature these creatures lived in was much warmer than previous records have shown." "Although we did not measure carbon dioxide, several studies suggest that greenhouse gases forty million years ago were similar to those levels that are forecast for the end of this century and beyond. Our work provides another piece of evidence that, in a time period with relatively high carbon dioxide levels, temperatures were higher and ice sheets were much smaller and likely to have been completely absent." The rock sequence from the cliff face covers a time span of 70,000 years and shows cyclical temperature variations with a period of about 18,000 years. The temperature oscillation is likely to be related to the Earth's orbital patterns. Cardiff University |
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| Related Antarctica Current Events and Antarctica News Articles Oceans' uptake of manmade carbon may be slowing The oceans play a key role in regulating climate, absorbing more than a quarter of the carbon dioxide that humans put into the air. New fossil plant discovery links Patagonia to New Guinea in a warmer past Fossil plants are windows to the past, providing us with clues as to what our planet looked like millions of years ago. West Antarctic ice sheet may not be losing ice as fast as once thought New ground measurements made by the West Antarctic GPS Network (WAGN) project, composed of researchers from The University of Texas at Austin, The Ohio State University, and The University of Memphis, suggest the rate of ice loss of the West Antarctic ice sheet has been slightly overestimated. Last time carbon dioxide levels were this high: 15 million years ago, scientists report You would have to go back at least 15 million years to find carbon dioxide levels on Earth as high as they are today, a UCLA scientist and colleagues report Oct. 8 in the online edition of the journal Science. NASA flies to Antarctica for largest airborne polar ice survey NASA begins a series of flights Oct. 15 to study changes to Antarctica's sea ice, glaciers and ice sheets. The flights are part of Operation Ice Bridge, a six-year campaign that is the largest airborne survey ever made of ice at Earth's polar regions. Peering under the ice of a collapsing polar coast Starting this month, a giant NASA DC-8 aircraft loaded with geophysical instruments and scientists will buzz at low level over the coasts of West Antarctica, where ice sheets are collapsing at a pace far beyond what scientists expected a few years ago. Laser technique has implications for detecting microbial life forms in Martian ice An innovative technique called L.I.F.E. imaging used successfully to detect bacteria in frozen Antarctic lakes could have exciting implications for demonstrating signs of life in the polar regions of Mars. Algae and pollen grains provide evidence of remarkably warm period in Antarctica's history For Sophie Warny, LSU assistant professor of geology and geophysics and curator at the LSU Museum of Natural Science, years of patience in analyzing Antarctic samples with low fossil recovery finally led to a scientific breakthrough. Global public health the focus of scientific conference Counterfeit and adulterated food and drugs and advances in measurement science used to detect them emerged as key themes of the Annual Scientific Meeting (ASM) hosted by the U.S. Pharmacopeial (USP) Convention. MSU scientist helps map potato genome; move will improve crop yield It's been cultivated for at least 7,000 years and spread from South America to grow on every continent except Antarctica. Now the humble potato has had its genome sequenced. More Antarctica Current Events and Antarctica News Articles |
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