This is the finding of scientists from the University of Southampton's School of Ocean and Earth Science at the National Oceanography Centre, Southampton (NOCS), reported in Nature.
The Eocene epoch (55 to 34 million years ago) was the last interval of sustained global warmth in Earth's history, a likely consequence of atmospheric carbon dioxide levels much higher than today. It has been known for some time that, at the end of the Eocene, ice sheets on Antarctica first expanded to close their modern size. However, in a recent controversial move, it was proposed that, despite the high global temperatures of the time, very large ice sheets existed 8 million years earlier, not just on Antarctica but also in the Northern Hemisphere.
New findings from NOCS researchers show that, if ice sheets did exist during the controversial interval they must have been small and would have been easily accommodated on Antarctica with no need to invoke Northern Hemisphere glaciation. This result is more in keeping with other geological records and climate model results suggesting that the threshold for ice sheet inception would have been crossed earlier in the Southern Hemisphere than in the Northern Hemisphere because the South Pole has a continent sitting over it (Antarctica) while the North Pole has an ocean (the Arctic).
The NOCS group also identifies a short-lived event immediately preceding the controversial interval during which ocean temperatures briefly increased, the deep ocean became more acidic and the carbon cycle was perturbed by the contribution of isotopically light carbon to the ocean/atmosphere system. This finding hints at the operation of carbon cycle processes common to those thought responsible for the famous transient extreme warming events that occurred between 50 and 55 million years ago, providing a focus for future work aimed at better understanding climate-carbon cycle feedbacks.
Kirsty Edgar, Dr Paul Wilson and Philip Sexton of the University of Southampton's School of Ocean and Earth Science, based at NOCS, used stable isotope analysis of fossil shells of foraminifera (microscopic marine organisms) and bulk sediment from deep-sea sediments to generate a record of climate change and estimate potential global ice volumes in the Eocene. Sediment cores were taken in the tropical Atlantic Ocean by the Ocean Drilling Program (ODP).
The Natural Environment Research Council funded this research via a UK ODP grant. Collaborator Yusuke Suganuma is based at the University of Tokyo, Japan.
Sarah Watts | alfa
NASA eyes Pineapple Express soaking California
24.02.2017 | NASA/Goddard Space Flight Center
'Quartz' crystals at the Earth's core power its magnetic field
23.02.2017 | Tokyo Institute of Technology
On January 15, 2009, Chesley B. Sullenberger was celebrated world-wide: after the two engines had failed due to bird strike, he and his flight crew succeeded after a glide flight with an Airbus A320 in ditching on the Hudson River. All 155 people on board were saved.
On January 15, 2009, Chesley B. Sullenberger was celebrated world-wide: after the two engines had failed due to bird strike, he and his flight crew succeeded...
In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport
Cells need to repair damaged DNA in our genes to prevent the development of cancer and other diseases. Our cells therefore activate and send “repair-proteins”...
The Fraunhofer IWS Dresden and Technische Universität Dresden inaugurated their jointly operated Center for Additive Manufacturing Dresden (AMCD) with a festive ceremony on February 7, 2017. Scientists from various disciplines perform research on materials, additive manufacturing processes and innovative technologies, which build up components in a layer by layer process. This technology opens up new horizons for component design and combinations of functions. For example during fabrication, electrical conductors and sensors are already able to be additively manufactured into components. They provide information about stress conditions of a product during operation.
The 3D-printing technology, or additive manufacturing as it is often called, has long made the step out of scientific research laboratories into industrial...
Nature does amazing things with limited design materials. Grass, for example, can support its own weight, resist strong wind loads, and recover after being...
13.02.2017 | Event News
10.02.2017 | Event News
09.02.2017 | Event News
27.02.2017 | Information Technology
27.02.2017 | Materials Sciences
24.02.2017 | Life Sciences