Mystery of the Earth's Polar Caps 41 Million Years Ago
For most of our planet's history until fairly recently, the overall pattern has been for the Earth to be hot, with no permanent ice to be found anywhere.
New research to test global ice volume approximately 41.6 million years ago shows that ice caps at this time, if they existed at all, would have been small and easily accommodated on Antarctica.
The findings contradict a recent controversial suggestion that Earth was extensively glaciated at this time despite having been much warmer than today, most likely because of high atmospheric carbon dioxide levels.
Researchers of the Ocean Drilling Program (ODP) Expedition 207 explored and sampled the Central Atlantic’s Demerara Rise in January and February of 2003. Using pinhead-sized fossils (foraminifera) – collected from sediments deep beneath the Atlantic Ocean, 380 km north of Suriname, South America, they concluded that large continental ice sheets did not exist in both hemispheres around 41 million years ago.
This result is more in keeping with other geological records and climate model results suggesting that the ice sheets were more likely to form earlier in the Southern Hemisphere than in the Northern Hemisphere because the South Pole is capped by a continent, Antarctica, whereas the North Pole is capped by the Arctic Ocean.
“The beauty of the new results," explained Paul Wilson, of the School of Ocean & Earth Science at the UK’s National Oceanography Center and lead proponent of ODP Expedition 207, "is that they resolve a big problem. How can there have been more ice than today during an interval that was much warmer than today? The answer is that there was not more ice – that idea was a mistake based on inadequate data. The results give us renewed confidence in our understanding of the sequence of geological events and thus the controls on ice sheet existence.”
“The research is a classic example of the amazing way in which the Earth System is so intricately integrated,” said co-proponent Dick Norris of University of California, San Diego, Scripps Institution of Oceanography. “Isn’t it a marvelous thing that we can learn so much about the polar continental ice caps by examining tiny fossils that lived on the sea floor at the equator.”
The team's research findings will be published in an article in Nature on August 23rd.
Posted by Casey Kazan.
Related Galaxy posts:
The Day the Seas Died: What Can the Greatest of All Extinction Events Teach Us About Climate Change?
The Timeline For 21st Century “Climate Change Events”
Bigger Threat than Global Warming -Mass Species Extinction
A "Flat World" Solution to Climate Change
Monitoring Climate Change -Experts Say We Need Lunar Observatories
It sounds like you are a global warming denier. I believe in liberal freedom and that is why these people should be sent to reeducation camps.
Posted by: Fremon Sandlewould | July 26, 2008 at 12:22 PM
Dear Casey: This comment has nothing to do with global warming, but I thought it more likely that you would read it if it were addressed directly to you.
While I enjoy DG, I must state that Josh Hill is almost impossible to read, as a result of his near-total grammatical incompetence and general level of incoherence. It is easy to spot a Josh Hill posting, since there will be a glaring fubar mistake in the first sentence. I never read his posts, feeling that scientific acumen does not preclude grammatical skill-- in fact that it is much more likely the truly intelligent will be competent grammatically as well as scientifically.
I prefer, immeasurably, the wit and lucidity of a Luke McKinney. Do not intend to pick on Josh--I wish him good fortune in making a living. (If you are too tender-hearted to reject his attempts, perhaps you could pay to have him take writing lessons.) His medium is the use of words, however, so why shouldn't he be expected to perform at a basic level? Is a major league manager picking on an underperforming player when he sends that player back to the minors? A physicist who could not perform basic mathematics would not be taken seriously. Why should those who CAN use words well be asked to take seriously a person who cannot, but who presumes to practice in their arena?
Again--my intention is not to single Josh out. (Many of your writers, yourself included, commit errors, and though I notice every one of them, I do not critique them, because on the whole you manage well enough, and I have been forced to accept well enough. Josh's garblings are more frequent by several orders of magnitude.) My intention instead is to point out that many of us care about thought, evidence, AND linguistic cogency. When you persist in subjecting us to such verbal blundering, the implicit message is that you do not care about those who are arguably among your more broadly intelligent readers. Perhaps you can afford to alienate us.
As one who has degrees in both mathematics and English, I maintain that mathematics is a language. One demonstrates clear thought at least as much by mastery of the written word as by mathematical competence.
I am quite certain this is so, and predict that before long The Daily Galaxy itself will be reporting on studies that link mathematical and linguistic competence. I can only hope that these reports will not have been written by Josh Hill.
Posted by: Jack Butler | July 27, 2008 at 12:03 PM
Dear Casey: This comment has nothing to do with global warming, but I thought it more likely that you would read it if it were addressed directly to you.
While I enjoy DG, I must state that Josh Hill is almost impossible to read, as a result of his near-total grammatical incompetence and general level of incoherence. It is easy to spot a Josh Hill posting, since there will be a glaring fubar mistake in the first sentence. I never read his posts, feeling that scientific acumen does not preclude grammatical skill-- in fact that it is much more likely the truly intelligent will be competent grammatically as well as scientifically.
I prefer, immeasurably, the wit and lucidity of a Luke McKinney. Do not intend to pick on Josh--I wish him good fortune in making a living. (If you are too tender-hearted to reject his attempts, perhaps you could pay to have him take writing lessons.) His medium is the use of words, however, so why shouldn't he be expected to perform at a basic level? Is a major league manager picking on an underperforming player when he sends that player back to the minors? A physicist who could not perform basic mathematics would not be taken seriously. Why should those who CAN use words well be asked to take seriously a person who cannot, but who presumes to practice in their arena?
Again--my intention is not to single Josh out. (Many of your writers, yourself included, commit errors, and though I notice every one of them, I do not critique them, because on the whole you manage well enough, and I have been forced to accept well enough. Josh's garblings are more frequent by several orders of magnitude.) My intention instead is to point out that many of us care about thought, evidence, AND linguistic cogency. When you persist in subjecting us to such verbal blundering, the implicit message is that you do not care about those who are arguably among your more broadly intelligent readers. Perhaps you can afford to alienate us.
As one who has degrees in both mathematics and English, I maintain that mathematics is a language. One demonstrates clear thought at least as much by mastery of the written word as by mathematical competence.
I am quite certain this is so, and predict that before long The Daily Galaxy itself will be reporting on studies that link mathematical and linguistic competence. I can only hope that these reports will not have been written by Josh Hill.
Posted by: Jack Butler | July 27, 2008 at 12:04 PM