Catastrophic Seepage and Climate
July 20, 2006
Catastrophic Seepage is the process where gas trapped at the seabed escapes in a catastrophic blowout. Catastrophic seepage explains how the powerful greenhouse gas, methane, which is trapped in vast quantities in the seabed, could escape to the atmosphere, enhance global warming, and push the global climate towards a tipping point, beyond which humanity will be unable to positively impact climate.
The study, Natural marine seepage blowout: Contribution to atmospheric methane was published July 20, 2006 in the prestigious journal, Global Biogeochemical Cycles, and generated significant interest. [see UCSB Press Release]. The article has been carried on about 30 news venues, including the Washington Post, Reuters, USA Today, MSNBC, and UPI.
The story:
• UCSB Seep Researchers made a seemingly small discovery - that seabed methane could reach the atmosphere through a new process: Catastrophic Seepage.
• Two important points need to be appreciated to understand the significance of Catastrophic Seepage.
1. Methane is a powerful, nasty greenhouse gas, warming the atmosphere twenty times more than carbon dioxide per molecule.
2. There are vast deposits of methane trapped at the deep sea bed, frozen in a type of ice called methane hydrate. And these deposits are really vast. Worse, they are meta-stable. A slight warming and they begin to transform directly from ice to gas. Three thousand times the amount of methane in the atmosphere is estimated locked in seabed hydrates.
• Hydrates were thought to decompose as gentle bubbling. When they do, the gas remains trapped in the deep sea and has no effect on the atmosphere.
• We discovered that when methane at the seabed belches explosively in a blowout - catastrophic seepage - then almost all the methane reaches the sea surface and the atmosphere.
• As seabed methane reaches the atmosphere, it increases greenhouse warming which leads to a warmer ocean and hence more hydrate destabilizing and belching - a viscious cycle.
• In order to destabilize the hydrates, it is not necessary to "warm" the entire ocean - only to create oceanic heat waves - wherein masses of warmer water travel further north than normal.
• If global warming continues, we may reach a tipping point wherein 'frozen' hydrocarbons (called hydrates), will release tremendous amounts of greenhouse gases.
• In a worst case scenario, the structural integrity of hydrate deposits will fail, leading to shelf failure and slumps generating tsunami's and threatening offshore facilities. Massive hydrate icebergs could then begin rising from the deep towards the surface (hydrate is buoyant). It is impossible to predict the outcome of such a scenario.
• Currently, we do not know the rate at which catastrophic seepage occurs from hydrates, although volcanic shaped seabed structures - pockmarks - suggest that seabed methane does erupt explosively. We do not know the current contribution from catastrophic seepage. We cannot predict future rates of catastrophic seepage. We do not know where we stand with regards to pushing climate past the tipping point.
Ira Leifer
Associate Researcher, Multiphase Fluid dynamics, Physical Oceanography, Meteorology, Bubble Processes, Marine Science Institute
Research interests focus on bubbles, bubble-plume dynamics, and oil in the environment including oily bubbles and oil slick evolution. Expertise in both bubble measurements, plume measurements and characterization, and bubble and plume numerical modeling. Other active interests include remote sensing and in-situ measurements of atmospheric methane, hydrate dissociation, bubble dissolution, and bubble formation from breaking waves.
Tel: 805-893-4931
Email: ira.leifer@bubbleology.com
Web: http://www.bubbleology.com
Bruce P. Luyendyk
Professor, Tectonics, Geophysics, Paleomagnetics, Dept of Earth Sciences
Research is divided into three main areas; 1) paleomagnetism and tectonics of southern California and Mojave desert; 2) structural studies in the Western Transverse Ranges, and offshore southern and central California; and 3) studies in Marie Byrd Land, west Antarctica. Research in all three areas involves the integration of various geophysical and structural techniques to address problems of tectonic evolution.
Tel: 805-893-3009
Email: luyendyk@geol.ucsb.edu
Web: http://www.geol.ucsb.edu/faculty/luyendyk
Jim Boles
Professor, Sedimentary Petrology, Diagenesis, Water-rock Interaction, Dept of Earth Sciences
Research centers on understanding the chemical and physical changes that occur in sediments from time of deposition up to and including deep burial and uplift (diagenesis). Identification of subsurface chemical reactions, sources and sinks of material involved, and quantifying rates and magnitudes of material movement.
Tel: 805-893-3042
Email: boles@geol.ucsb.edu
Web: http://www.geol.ucsb.edu/faculty/boles
Jordan F. Clark
Assistant Professor, Hydrogeology, Agueous Geochemistry, Dept of Earth Sciences
Research interests lie in the general field of aqueous geochemistry and center on: 1) the transport of water and dissolved material in groundwater, surface waters, and the coastal ocean; 2) how flow patterns affect water quality; 3) gas exchange across the air-water interface; 4) climate change during the last 30,000 yr. These questions are examined using experiments conducted by introducing chemical tracers into the water bodies, plus analysis of flow patterns, residence times, and mixing rates inferred from the distribution of natural and anthropogenic tracers.
Tel: 805-893-7838
Email: jfclark@geol.ucsb.edu
Web: http://www.geol.ucsb.edu/faculty/jfclark
