Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Ancient Greenland methane study good news for planet

24.04.2009
An analysis of ancient Greenland ice suggests a spike in the greenhouse gas methane about 11,600 years ago originated from wetlands rather than the ocean floor or from permafrost, a finding that is good news according to the University of Colorado at Boulder scientist who led the study.

Methane bound up in ocean sediments and permafrost, called methane clathrate, has been a concern to scientists because of its huge volume, greenhouse gas potency and potential for release during periods of warming, said Vasilii Petrenko, a CU-Boulder postdoctoral fellow and lead study author.

If just 10 percent of methane from clathrates -- an ice-like substance composed of methane and water -- were suddenly released into Earth's atmosphere, the resulting increase in the greenhouse effect would be equivalent to a 10-fold increase in atmospheric carbon dioxide, he said.

Using carbon 14 as a "tracer" to date and distinguish wetland methane from methane clathrates, an international team determined the methane jump 11,600 years ago likely emanated primarily from Earth's wetlands. "From a global warming standpoint, this appears to be good news," said Petrenko of CU-Boulder's Institute of Arctic and Alpine Research, lead author on a paper that was published in Science on April 24.

Methane is the third most powerful greenhouse gas behind water vapor and CO2 and accounts for roughly 20 percent of the human-caused increase in the greenhouse effect.

As Earth emerged from the last ice age, temperatures in some places in the Northern Hemisphere shot up about 18 degrees Fahrenheit in just 20 years, said Petrenko. Scientists have been concerned that such abrupt warming events could trigger huge oceanic methane "burps" caused by the dissociation of seafloor clathrates, providing a positive climate feedback mechanism that could drive up Earth's temperatures still further.

"If we found that clathrates release a lot of methane to the atmosphere during abrupt episodes of warming, that could signal big trouble for the planet, " said Petrenko. "But even though wetlands appear be the primary source, it's still something to be concerned about."

Methane emitted from human activities like rice cultivation, livestock, the burning of grasslands, forests and wood fuels, gas leaks from fossil fuel production and waste management activities have nearly tripled methane concentrations in Earth's atmosphere in the past 250 years, Petrenko said. The amount of carbon held in methane clathrate deposits on Earth may equal the amount of carbon in all oil, coal and gas reserves on the planet, he said.

Study co-authors were from the Scripps Institution of Oceanography, Oregon State University, the Australian Nuclear Science and Technology Organisation, the National Institute of Water and Atmospheric Research in New Zealand, Danish Technical University and the Commonwealth Scientific and Industrial Research Organisation in Australia. Petrenko conducted most of the research as part of his doctoral thesis at the Scripps Institution of Oceanography under Professor Jeffrey Severinghaus.

The research team extracted several tons of ancient ice from the western margin of the Greenland ice sheet at a site called Pakitsoq, the largest ice samples ever recovered for a climate change study. The researchers cut the ice into blocks with electric chain saws, dumped 17 cubic feet at a time into a vacuum melting tank heated by powerful propane torches, and transferred ancient air released from bubbles in the ice into cylinders for subsequent laboratory analysis, Petrenko said.

The effort, which lasted five field-seasons, was "an undertaking of epic proportions," said Petrenko. "This was the first measurement of its kind, and we really pushed the envelope," he said. "It represents a major advance in analytical methods for studying ancient ice."

Methane clathrates are only stable in conditions that combine cold temperatures and high pressures. Some scientists suspect that a swift and massive warming in the early Cenozoic era about 56 million years ago may have been triggered by huge methane releases from clathrates into the atmosphere, Petrenko said.

Methane levels in Earth's atmosphere increased about 2 percent from about A.D. 1 to 1000 and decreased by 2 percent from 1000 to 1700, which may have been due in part to decreased landscape burning by indigenous people in the Americas devastated by introduced diseases, according to a 2005 CU-Boulder study. About 60 percent of atmospheric methane is now generated from human-related activities, according to the International Panel on Climate Change.

The 2009 Greenland ice study was funded by the National Science Foundation, the American Chemical Society and several other agencies. Petrenko's postdoctoral fellowship at CU-Boulder is funded by The University Corporation for Atmospheric Research.

Contact: Vasilii Petrenko, 303-492-7132 Vasilii.petrenko@colorado.edu
Jim Scott, 303-492-3114

Vasilii Petrenko | EurekAlert!
Further information:
http://www.colorado.edu

More articles from Earth Sciences:

nachricht Wintertime Arctic sea ice growth slows long-term decline: NASA
07.12.2018 | NASA/Goddard Space Flight Center

nachricht Why Tehran Is Sinking Dangerously
06.12.2018 | 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: 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 >>>