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:3/31/2016)... RATON, Florida , March 31, 2016 ... LEGX ) ("LegacyXChange" or the "Company") ... for potential users of its soon to be launched ... video ( https://www.youtube.com/channel/UCyTLBzmZogV1y2D6bDkBX5g ) will also provide ... the use of DNA technology to an industry that ...
(Date:3/22/2016)... and SANDY, Utah , ... which operates the highest sample volume laboratory in ... Genomics and UNIConnect, leaders in clinical sequencing informatics and ... launch of a project to establish the informatics infrastructure ... NSO has been contracted by the Ontario ...
(Date:3/15/2016)... 15, 2016 Yissum Research Development Company ... company of the Hebrew University, announced today the formation ... technology of various human biological indicators. Neteera Technologies has ... from private investors. ... detection of electromagnetic emissions from sweat ducts, enables reliable ...
Breaking Biology News(10 mins):
(Date:4/27/2016)... ... , ... Shimadzu Scientific Instruments (SSI) will be showcasing a ... and Expo. Shimadzu’s high-performance instruments enable laboratories to test cannabis products for potency, ... by booth 1021 to learn how Shimadzu’s instruments can help improve QA/QC testing, ...
(Date:4/27/2016)... ... April 27, 2016 , ... Most consumers engage with ... recognition for secure access, voice recognition for hands-free communication, and facial recognition to ... with biometrics technology today. But if they asked Joey Pritikin, Vice President ...
(Date:4/27/2016)... SILVER SPRING, Md. and RESEARCH ... -- United Therapeutics Corporation (NASDAQ: UTHR ) announced ... Co-Chief Executive Officer, of United Therapeutics will provide an ... Deutsche Bank 41 st Annual Health Care Conference. ... May 5, 2016, at 10:00 a.m. Eastern Time, and ...
(Date:4/27/2016)... ... April 27, 2016 , ... NDA ... joined the company as an Expert Consultant. Mr. Clark was formerly a ... managing the development of small molecule monographs based on analytical methods. NDA ...
Breaking Biology Technology: