Methane may be answer to 56-million-year question

11/8/2011

Mike Williams
713-348-6728
mikewilliams@rice.edu

Methane may be answer to 56-million-year question

Rice researchers show ocean could have contained enough methane to cause drastic climate change

The release of massive amounts of carbon from http://en.wikipedia.org/wiki/Methane_hydrate">methane hydrate frozen under the seafloor 56 million years ago has been linked to the greatest change in global climate since a http://en.wikipedia.org/wiki/Cretaceous%E2%80%93Tertiary_extinction_event">dinosaur-killing asteroid presumably hit Earth 9 million years earlier. New calculations by researchers at Rice University show that this long-controversial scenario is quite possible.

Nobody knows for sure what started the incident, but there's no doubt Earth's temperature rose by as much as 6 degrees Celsius. That affected the planet for up to 150,000 years, until excess carbon in the oceans and atmosphere was reabsorbed into sediment.

Earth's ecosystem changed and many species went extinct during the http://en.wikipedia.org/wiki/Paleocene-Eocene_Thermal_Maximum">Paleocene-Eocene Thermal Maximum (PETM) 56 million years ago, when at least 2,500 gigatonnes of carbon, eventually in the form of carbon dioxide, were released into the ocean and atmosphere. (The era is described in great detail in a recent http://ngm.nationalgeographic.com/2011/10/hothouse-earth/kunzig-text">National Geographic feature.)

A new report by Rice scientists in http://www.nature.com/ngeo/journal/vaop/ncurrent/abs/ngeo1301.html">Nature Geoscience suggests that at the time, even though methane-containing gas hydrates – the "ice that burns" – occupied only a small zone of sediment under the seabed before the PETM, there could have been as much stored then http://www.media.rice.edu/media/NewsBot.asp?MODE=VIEW&ID=16163">as there is now.

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