Navigation Links
CO2 drop and global cooling caused Antarctic glacier to form
Date:2/26/2009

New Haven, Conn. Global climate rapidly shifted from a relatively ice-free world to one with massive ice sheets on Antarctica about 34 million years ago. What happened? What changed? A team of scientists led by Yale geologists offers a new perspective on the nature of changing climatic conditions across this greenhouse-to-icehouse transitionone that refutes earlier theories and has important implications for predicting future climate changes.

Detailed in the February 27 issue of Science, their data disproves a long-held idea that massive ice growth in the Antarctic was accompanied by little to no global temperature change.

This report shows that before the Southern Hemisphere ice expansion, high-latitude temperatures were at least 10C (about 18˚F) warmer than previously estimated and that there was a 5˚C - 10˚C drop in surface-water temperature during the climate transition.

"Previous reconstructions gave no evidence of high-latitude cooling," according to senior author Mark Pagani, professor of geology and geophysics at Yale. "Our data demonstrate a clear temperature drop in both hemispheres during this time."

Their conclusions are based on sea-surface "temperature proxies" calculations of temperature based on the distribution of specific organic molecules from ancient plankton that only lived at certain temperatures and were later preserved in ocean sediments. These molecules were assayed in ocean cores collected by the Integrated Ocean Drilling Program (IODP) and earlier marine programs that study Earth history by coring deep-ocean sediments and crust around the world.

"Temperatures in some regions, just before the Antarctic glaciers formed, were surprisingly higher than current climate models predicted, suggesting that these models underestimate high-latitude warming under high CO2 conditions," said lead author Zhonghui Liu, Pagani's postdoctoral associate who is now an assistant professor at the University of Hong Kong. Further, he said, the substantial cooling that occurred in both Northern and Southern high latitudes suggests that a decline in CO2 level, rather than a localized change of ocean circulation drove the climate transition.

The ice formed over Antarctica in about 100,000 years, which is an "overnight" shift in geological terms. "Just over thirty-five million years ago, 'poof,' there was an ice sheet where there had been subtropical temperatures before," said Co-author Matthew Huber of Purdue University.

Another theory refuted by this study is the notion that ice-expansion also occurred in the Northern Hemisphere during this time a supposition poorly supported by physical evidence of glacier formation in that region, say the Yale scientists.

There are about 70 meters of vertical sea level rise represented in the ice sheets of Antarctica. And, there are many questions regarding the glacier's stability, the temperature thresholds that would cause radical glacier melting, and the rate at which it would change, according to Pagani. "Our findings point to the difficulty of modeling accurate temperatures under higher CO2 in this critical region."


'/>"/>

Contact: Janet Rettig Emanuel
janet.emanuel@yale.edu
203-432-2157
Yale University
Source:Eurekalert  

Related biology news :

1. Global Warming and the Habitability of Planet Earth, Sept. 26
2. Green skies: Engineers work may reduce jet travels role in global warming
3. Scientists in first global study of poison gas in the atmosphere
4. North Americas northernmost lake affected by global warming
5. IEEE-USA innovation forum will help prepare US tech leaders to prosper in a global marketplace
6. Majority of Americans want local action on global warming, says poll
7. International team of scientists warns of climate changes impact on global river flow
8. Changing the global dietary environment
9. Global deal fuels QUTs world-changing research
10. NIH hosts event to launch Council of Science Editors global theme issue
11. Agricultural soil erosion is not adding to global warming
Post Your Comments:
*Name:
*Comment:
*Email:
Related Image:
CO2 drop and global cooling caused Antarctic glacier to form
(Date:3/30/2017)... 30, 2017  On April 6-7, 2017, Sequencing.com will ... hackathon at Microsoft,s headquarters in ... focus on developing health and wellness apps that provide ... the Genome is the first hackathon for personal ... largest companies in the genomics, tech and health industries ...
(Date:3/29/2017)...  higi, the health IT company that operates the ... , today announced a Series B investment from ... The new investment and acquisition accelerates higi,s strategy to ... population health activities through the collection and workflow integration ... collects and secures data today on behalf of over ...
(Date:3/24/2017)... 2017 The Controller General of Immigration from Maldives ... Algeen have received the prestigious international IAIR Award for the most ... Reading ... Maldives ... Abdulla Algeen (small picture on the right) have received the IAIR award ...
Breaking Biology News(10 mins):
(Date:4/21/2017)... ... April 21, 2017 , ... Frederick Innovative Technology Center, Inc. ... bio and technology start-ups, is hosting “Celebration Friday” (a festive gathering highlighting client ... with libations and networking at 3:30 p.m. at FITCI’s 4539 Metropolitan Court location, ...
(Date:4/20/2017)... ... April 20, 2017 , ... USDM Life Sciences , the ... and healthcare industries, is pleased to announce Holger Braemer as Vice President ... Europe GmbH” based in Germany. , Braemer is an integral part of USDM’s ...
(Date:4/20/2017)... CA (PRWEB) , ... April 20, 2017 , ... ... of clinical trials worldwide, announced today that they were named one of the ... which covers the latest developments in the pharmaceutical industry. , “We take pride in ...
(Date:4/19/2017)... (PRWEB) , ... April 18, 2017 , ... ... 1970s and has been a key device for generating monodisperse droplets of known ... droplet processes and for generating monodisperse solid particles by drying monodisperse droplets. ...
Breaking Biology Technology: