Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Study bolsters greenhouse effect theory, solves ice age mystery

27.01.2005


Critics who dismiss the importance of greenhouse gases as a cause of climate change lost one piece of ammunition this week. In a new study, scientists found further evidence of the role that greenhouse gases have played in Earth’s climate.



In Thursday’s issue of the journal Geology, Ohio State University scientists report that a long-ago ice age occurred 10 million years earlier than once thought. The new date clears up an inconsistency that has dogged climate change research for years.

Of three ice ages that occurred in the last half-billion years, the earliest ice age posed problems for scientists, explained Matthew Saltzman, assistant professor of geological sciences at Ohio State.


Previous studies suggested that this particular ice age happened during a time that should have been very warm, when volcanoes all over the earth’s surface were spewing carbon dioxide (CO2) and other heat-trapping greenhouse gases into the atmosphere.

With CO2 levels as much as 20 times higher than today, the late Ordovician period (460-440 million years ago) wasn’t a good time for growing ice.

Critics have pointed to the inconsistency as a flaw in scientists’ theories of climate change. Scientists have argued that today’s global climate change has been caused in part by buildup of CO2 in the atmosphere resulting from fossil fuel emissions.

But, critics have countered, if CO2 truly raises global temperatures, how could an ice age have occurred when a greenhouse effect much greater than today’s was in full swing?

The answer: This particular ice age didn’t begin when CO2 was at its peak -- it began 10 million years earlier, when CO2 levels were at a low. “Our results are consistent with the notion that CO2 concentrations drive climate.”

Saltzman and doctoral student Seth Young found that large deposits of quartz sand in Nevada and two sites in Europe -- Norway and Estonia -- formed around the same time, 440 million years ago. The scientists suspect that the sand formed when water levels fell low enough to expose quartz rock, so that wind and rain could weather the rock into sand.

The fact that the deposits were found in three different sites suggests that sea levels may have been low all over the world at that time, likely because much of the planet’s water was bound in ice at the poles, Saltzman said.

Next, the scientists examined limestone sediments from the sites and determined that there was a relatively large amount of organic carbon buried in the oceans -- and, by extension, relatively little CO2 in the atmosphere -- at the same time.

Taken together, the evidence suggests that the ice began to build up some 10 million years earlier than when volcanoes began pumping the atmosphere full of the CO2 that ended the Ordovician ice age.

For Saltzman, the find solves a long-standing mystery.

Though scientists know with a great degree of certainty that atmospheric CO2 levels drive climate change, there are certain mismatches in the geologic record, such as the Ordovician ice age -- originally thought to have begun 443 million years ago -- that seem to counter that view.

“How can you have ice when CO2 levels are through the roof? That was the dilemma that we were faced with. I think that now we have good evidence that resolves this mismatch,” Saltzman said.

Scientists at the three sites previously attributed these quartz deposits to local tectonic shifts. But the new study shows that the conditions that allowed the quartz sand to form were not local.

“If sea level is dropping globally at the same time, it can’t be a local tectonic feature,” Saltzman said. “It’s got to be the result of a global ice buildup.”

Saltzman wants to bolster these new results by examining sites in Russia -- where he hopes to find more evidence of sea level drop -- and in parts of South America and North Africa, which would have been covered in ice at the time.

Matthew Saltzman | EurekAlert!
Further information:
http://www.osu.edu

More articles from Earth Sciences:

nachricht In times of climate change: What a lake’s colour can tell about its condition
21.09.2017 | Leibniz-Institut für Gewässerökologie und Binnenfischerei (IGB)

nachricht Did marine sponges trigger the ‘Cambrian explosion’ through ‘ecosystem engineering’?
21.09.2017 | Helmholtz-Zentrum Potsdam - Deutsches GeoForschungsZentrum GFZ

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Highly precise wiring in the Cerebral Cortex

Our brains house extremely complex neuronal circuits, whose detailed structures are still largely unknown. This is especially true for the so-called cerebral cortex of mammals, where among other things vision, thoughts or spatial orientation are being computed. Here the rules by which nerve cells are connected to each other are only partly understood. A team of scientists around Moritz Helmstaedter at the Frankfiurt Max Planck Institute for Brain Research and Helene Schmidt (Humboldt University in Berlin) have now discovered a surprisingly precise nerve cell connectivity pattern in the part of the cerebral cortex that is responsible for orienting the individual animal or human in space.

The researchers report online in Nature (Schmidt et al., 2017. Axonal synapse sorting in medial entorhinal cortex, DOI: 10.1038/nature24005) that synapses in...

Im Focus: Tiny lasers from a gallery of whispers

New technique promises tunable laser devices

Whispering gallery mode (WGM) resonators are used to make tiny micro-lasers, sensors, switches, routers and other devices. These tiny structures rely on a...

Im Focus: Ultrafast snapshots of relaxing electrons in solids

Using ultrafast flashes of laser and x-ray radiation, scientists at the Max Planck Institute of Quantum Optics (Garching, Germany) took snapshots of the briefest electron motion inside a solid material to date. The electron motion lasted only 750 billionths of the billionth of a second before it fainted, setting a new record of human capability to capture ultrafast processes inside solids!

When x-rays shine onto solid materials or large molecules, an electron is pushed away from its original place near the nucleus of the atom, leaving a hole...

Im Focus: Quantum Sensors Decipher Magnetic Ordering in a New Semiconducting Material

For the first time, physicists have successfully imaged spiral magnetic ordering in a multiferroic material. These materials are considered highly promising candidates for future data storage media. The researchers were able to prove their findings using unique quantum sensors that were developed at Basel University and that can analyze electromagnetic fields on the nanometer scale. The results – obtained by scientists from the University of Basel’s Department of Physics, the Swiss Nanoscience Institute, the University of Montpellier and several laboratories from University Paris-Saclay – were recently published in the journal Nature.

Multiferroics are materials that simultaneously react to electric and magnetic fields. These two properties are rarely found together, and their combined...

Im Focus: Fast, convenient & standardized: New lab innovation for automated tissue engineering & drug

MBM ScienceBridge GmbH successfully negotiated a license agreement between University Medical Center Göttingen (UMG) and the biotech company Tissue Systems Holding GmbH about commercial use of a multi-well tissue plate for automated and reliable tissue engineering & drug testing.

MBM ScienceBridge GmbH successfully negotiated a license agreement between University Medical Center Göttingen (UMG) and the biotech company Tissue Systems...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

“Lasers in Composites Symposium” in Aachen – from Science to Application

19.09.2017 | Event News

I-ESA 2018 – Call for Papers

12.09.2017 | Event News

EMBO at Basel Life, a new conference on current and emerging life science research

06.09.2017 | Event News

 
Latest News

Comet or asteroid? Hubble discovers that a unique object is a binary

21.09.2017 | Physics and Astronomy

Cnidarians remotely control bacteria

21.09.2017 | Life Sciences

Monitoring the heart's mitochondria to predict cardiac arrest?

21.09.2017 | Health and Medicine

VideoLinks
B2B-VideoLinks
More VideoLinks >>>