Embargoed Until 1 p.m. Eastern Time:
NSF PR 03-140 - December 17, 2003
Media contact: Cheryl Dybas (703) 292-7734 [email protected] Program contact: Enriqueta Barrera (703) 292-8551 [email protected] Stable Isotope Data Provide Evidence for Huge Global Methane Release about 600 Million Years Ago
Led to Rapid Warming of Earth's Climate
The cap carbonate contains disrupted and cemented textures similar to modern methane seeps underneath the seafloor.
Photo by Ganqing Jiang at the University of California at Riverside.
Select image for larger version
(Size: 109KB)
Note About Images Arlington, Va.—The Earth's most severe ice coverings are thought to have occurred about 600 million years ago, with frozen ice sheets covering much of the globe. Some scientists have suggested the oceans froze over during that time, resulting in a white planet or "snowball Earth" that would have reflected much of the Sun's heat and resulted in a condition of persistent extreme cold. Now, in a study published in the December 18 issue of the journal Nature, scientists describe new evidence from south China that explains how the planet might have thawed from its icy past. According to geologist Ganqing Jiang of the University of California at Riverside and lead author of the paper, the results point to the release of the powerful "greenhouse gas" methane, than to the release of carbon dioxide, which has been believed to be the mechanism by which the Earth re-warmed. Where did the methane come from? "It probably arose from deposits known as methane hydrates," said Jiang. "Methane hydrates likely were widespread in sediments deposited under very cold conditions and would have been released as a gas at the end of this ice age, rapidly warming Earth’s climate." Methane hydrates usually are locked away in Earth's sediments, said Herman Zimmerman, director of the National Science Foundation's (NSF) division of earth sciences, which funded the research. NSF is the federal agency responsible for supporting basic science, engineering and education research. "But large amounts of greenhouse gases may be released from those sediments, during so-called 'destablization events.'" If this hypothesis is correct, added Enriqueta Barrera, geology and paleontology program director at NSF, "this could have been the largest such release of methane in Earth history. This is an important process needing further study, because a similar event could occur in the future as a consequence of global warming." The new data provide strong support for an idea first published by Jiang's coauthors, geologists Martin Kennedy, also at UC-Riverside, and Nicholas Christie-Blick of Columbia University's Lamont-Doherty Earth Observatory. Features observed in many of the sediments studied seemed to indicate a role for a release of methane from exposed methane hydrates. The new data are based on especially well preserved samples, say the scientists. "If this study is borne out by further research, it may point to the largest such methane hydrate release in more than four billion years of Earth history," said Jiang. "Such an event would have had a profound impact on global climate." The National Science Foundation (NSF) is an independent federal agency that supports fundamental research and education across all fields of science and engineering, with an annual budget of nearly $5.3 billion. NSF funds reach all 50 states through grants to nearly 2,000 universities and institutions. Each year, NSF receives about 30,000 competitive requests for funding, and makes about 10,000 new funding awards. The NSF also awards over $200 million in professional and service contracts yearly. Receive official NSF news electronically through the e-mail delivery system, NSFnews. To subscribe, send an e-mail message to [email protected]. In the body of the message, type "subscribe nsfnews" and then type your name. (Ex.: "subscribe nsfnews John Smith") Useful NSF Web Sites:
NSF Home Page: http://www.nsf.gov
News Highlights: http://www.nsf.gov/od/lpa
Newsroom: http://www.nsf.gov/od/lpa/news/media/start.htm
Science Statistics: http://www.nsf.gov/sbe/srs/stats.htm
Awards Searches: http://www.fastlane.nsf.gov/a6/A6Start.htm
National Science Foundation
Office of Legislative and Public Affairs
4201 Wilson Boulevard
Arlington, Virginia 22230, USA
Tel: 703-292-8070
FIRS: 800-877-8339 | TDD: 703-292-5090
| 