Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Scientists study ocean to understand global cooling

07.01.2005


The depth in the ocean where calcium carbonate dissolves at a faster rate than it is deposited is called the calcite compensation depth (CCD). At present this depth is approximately 4,500 meters (14,700 feet) with some variation between and within ocean basins. Because the CCD is linked to ocean acidity, which is, in turn, linked to atmospheric carbon dioxide concentrations and, hence, to global climate, it is important for scientists to understand the impact of possible changes in its depth.

In the current issue of Nature, URI Graduate School of Oceanography (GSO) visiting scientist Helen Coxall describes how the deepening of the CCD in the Pacific Ocean correlated to global cooling approximately 34 million years ago, when the first significant permanent ice sheets appeared on Antarctica. Other members of the scientific team include Paul Wilson, Southampton Oceanography Center, UK, Heiko Pälike and Jan Backman, University of Stockholm, Sweden, and Caroline H. Lear, Rutgers University, New Jersey.

"This event 34 million years ago marks the transition from a warm ’greenhouse’ climate state, when atmospheric carbon dioxide levels were naturally high and there was no or very little ice at the poles, to the cold glaciated climate state of the modern world that was characterized by lower carbon dioxide," said Coxall. "It is therefore equivalent to global warming in reverse. The results of our study are crucial to the understanding of how climate change works, especially how rapidly major changes in ice-sheet growth and sea level rise and fall occur under altered conditions of atmospheric carbon dioxide."



Coxall and her colleagues analyzed sediment records and found that the deepening of the CCD was more rapid than previously documented and occurred in two jumps of about 40,000 years each, in step with the onset of Antarctic ice-sheet growth. The 40,000-year interval was separated by a plateau of 200,000 years.

The glaciation began after the Earth entered a cooler phase during an interval when the Earth’s orbit of the Sun favored cool summers. The researchers’ observations suggest that it was the prolonged absence of warm summers, inhibiting summer snow melt, not the occurrence of cool winters favoring accumulation, that was important for establishing the first major ice sheets on Antarctica. Although the pattern of Earth’s orbital configuration was the ultimate trigger for creating conditions that led to ice-sheet growth, a natural long-term decrease in atmospheric carbon dioxide levels, which promoted global cooling, was responsible for increasing Earth’s sensitivity to this factor.

In addition, analysis of the data indicates that along with the growth of the Antarctic ice sheet, glaciation in the Northern Hemisphere must also have been taking place.

Lisa Cugini | EurekAlert!
Further information:
http://www.gso.uri.edu

More articles from Ecology, The Environment and Conservation:

nachricht Machine learning helps predict worldwide plant-conservation priorities
04.12.2018 | Ohio State University

nachricht From the Arctic to the tropics: researchers present a unique database on Earth’s vegetation
20.11.2018 | Martin-Luther-Universität Halle-Wittenberg

All articles from Ecology, The Environment and Conservation >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Researchers develop method to transfer entire 2D circuits to any smooth surface

What if a sensor sensing a thing could be part of the thing itself? Rice University engineers believe they have a two-dimensional solution to do just that.

Rice engineers led by materials scientists Pulickel Ajayan and Jun Lou have developed a method to make atom-flat sensors that seamlessly integrate with devices...

Im Focus: Three components on one chip

Scientists at the University of Stuttgart and the Karlsruhe Institute of Technology (KIT) succeed in important further development on the way to quantum Computers.

Quantum computers one day should be able to solve certain computing problems much faster than a classical computer. One of the most promising approaches is...

Im Focus: Substitute for rare earth metal oxides

New Project SNAPSTER: Novel luminescent materials by encapsulating phosphorescent metal clusters with organic liquid crystals

Nowadays energy conversion in lighting and optoelectronic devices requires the use of rare earth oxides.

Im Focus: A bit of a stretch... material that thickens as it's pulled

Scientists have discovered the first synthetic material that becomes thicker - at the molecular level - as it is stretched.

Researchers led by Dr Devesh Mistry from the University of Leeds discovered a new non-porous material that has unique and inherent "auxetic" stretching...

Im Focus: The force of the vacuum

Scientists from the Theory Department of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science (CFEL) in Hamburg have shown through theoretical calculations and computer simulations that the force between electrons and lattice distortions in an atomically thin two-dimensional superconductor can be controlled with virtual photons. This could aid the development of new superconductors for energy-saving devices and many other technical applications.

The vacuum is not empty. It may sound like magic to laypeople but it has occupied physicists since the birth of quantum mechanics.

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

New Plastics Economy Investor Forum - Meeting Point for Innovations

10.12.2018 | Event News

EGU 2019 meeting: Media registration now open

06.12.2018 | Event News

Expert Panel on the Future of HPC in Engineering

03.12.2018 | Event News

 
Latest News

Small but ver­sat­ile; key play­ers in the mar­ine ni­tro­gen cycle can util­ize cy­anate and urea

10.12.2018 | Life Sciences

New method gives microscope a boost in resolution

10.12.2018 | Physics and Astronomy

Carnegie Mellon researchers probe hydrogen bonds using new technique

10.12.2018 | Life Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>