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Gas Releases Helped End Ice Ages

Larry O'Hanlon, Discovery News

"Now, here's the rub: While one of these processes acts as negative feedback mechanism for climate change (namely sea-level lowering during glacial periods)," said Hornbach, "the other mechanism (ocean temperature warming) triggers a positive feedback mechanism that potentially injects large quantities of methane into an already warming climate."

There's also the danger that the warming of hydrates could weaken undersea slopes and cause massive submarine landslides that belch huge amounts of methane into the atmosphere, Hornbach told Discovery News. That may even be what was happening in those ice age methane releases.

"In fact, two studies back in 2003 and 2004 indicate that near-critical gas pressures may exist at many gas hydrate provinces, indicating that many ... are at the brink of instability, and only very minor changes in temperature or pressure could lead to structural failure, and methane gas release," he said.

Nor will the slight additional rise in sea level stave off these troubles by putting today's gas hydrates under more pressure, said Hornbach.

"A few tens of meters of sea level rise, will not significantly offset the effects of a few degrees of ocean temperature warming," Hornbach said.

Related Links:

Larry O'Hanlon's blog: Earth Impacts

USGS: Gas Hydrates -- A New Fronteir