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 Science News and Science Current Events Tag Cloud This tag cloud is a visual representation of term frequencies of random science news topics with common terms grouped together and emphasized by their display size. Smart-1 Liver Cells Preterm Infants Cancer Development Biomolecules Pheromones Nerve Cells Acetaminophen Physical Activity Hemophilia Liver Disease Genes Neurons HIV infection Psychotherapy Tooth Loss Carbon Dioxide Ethanol Production Exercise Heart Failure San Andreas Fault Stem Cell Invisibility Cloak Thyroid Cognitive Function
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Related Antarctica Current Events and Antarctica News Articles Ice Sheets Can Retreat Modern glaciers, such as those making up the Greenland and Antarctic ice sheets, are capable of undergoing periods of rapid shrinkage or retreat, according to new findings by paleoclimatologists at the University at Buffalo. Breakthrough made in assessing marine phytoplankton health Researchers from Oregon State University, NASA and other organizations said today that they have succeeded for the first time in measuring the physiology of marine phytoplankton through satellite measurements of its fluorescence - an accomplishment that had been elusive for years. Unstated assumptions color Arctic sovereignty claims Settling the growing debate over ownership of Arctic Ocean resources is complicated by the fact that the various countries involved have different understandings of the geography of the place. Peering deep into space People have always wondered where we, our Earth, our galaxy, come from. A group of scientist has now driven that quest one step further and taken a peak at how the stars that gave rise to most of the material found on our universe formed over cosmic history. Melting threat from West Antarctic Ice Sheet may be less than expected, could hit US hardest While a total or partial collapse of the West Antarctic Ice Sheet as a result of warming would not raise global sea levels as high as some predict, levels on the U.S. seaboards would rise 25 percent more than the global average and threaten cities like New York, Washington, D.C., and San Francisco, according to a new study. Threat from West Antarctica less than previously believed The potential contribution to sea level rise from a collapse of the West Antarctic Ice Sheet (WAIS) have been greatly overestimated, according to a new study published in the journal Science. Global monsoon drives long-term carbon cycles in the ocean Monsoon is a global system, and many arrays of evidence indicate that it drives long-term cyclicity of the carbon reservoir in the global ocean. Ocean Carbon: A Dent in the Iron Hypothesis Oceanographers Jim Bishop and Todd Wood of the U.S. Department of Energy's Lawrence Berkeley National Laboratory have measured the fate of carbon particles originating in plankton blooms in the Southern Ocean, using data that deep-diving Carbon Explorer floats collected around the clock for well over a year. As world warms, water levels dropping in major rivers Rivers in some of the world's most populous regions are losing water, according to a comprehensive study of global stream flows. Increasing levels of rare element found worldwide Dartmouth researchers have determined that the presence of the rare element osmium is on the rise globally. They trace this increase to the consumption of refined platinum, the primary ingredient in catalytic converters, the equipment commonly installed in cars to reduce smog. More Antarctica Current Events and Antarctica News Articles |
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