Runaway Global Warming 635 Million Years Ago

LiveScience.com on Yahoo ^ | 5/28/08

[NormsRevenge]

A sudden and extreme case of runaway global warming 635 million years ago was caused by an abrupt release of methane, a powerful greenhouse gas, scientists said today.

The methane seeped from ice sheets that covered much of the planet toward the end of a frigid era called Snowball Earth. The gas escaped gradually at first and then very quickly from clathrates, or methane ice that forms and stabilizes beneath water ice sheets. As the water ice melted, pressure was relieved on the clathrates and they began to de-gas.

The transition represents one of the earliest known cases of what scientists now call a climatic tipping-point.

The big question scientists are now pondering: Could it happen again?

"Our findings document an abrupt and catastrophic global warming that led from a very cold, seemingly stable climate state to a very warm, also stable, climate state - with no pause in between," said geologist Martin Kennedy of the University of California at Riverside, who led the research team.

"What we now need to know is the sensitivity of the trigger," Kennedy said. "How much forcing does it take to move from one stable state to the other - and are we approaching something like that today with current carbon dioxide warming?"

Also called marsh gas, methane is a colorless, odorless gas. As a greenhouse gas, it is about 30 times more potent than carbon dioxide.

Methane clathrates still exist in Arctic permafrost and beneath the oceans at continental margins. Kennedy said it's possible that very little warming could unleash this trapped methane, potentially warming the planet by tens of degrees.

Kennedy and colleagues collected hundreds of marine sediment samples in South Australia for stable isotope analysis, an important tool used in climate reconstruction. They found the broadest range of oxygen isotopic variation ever reported from marine sediments, which they attribute to melting waters in ice sheets as well as destabilization of clathrates by glacial meltwater.

"Today we're conducting a global-scale experiment with Earth's climate system," Kennedy said, "and witnessing an unprecedented rate of warming, all with little or no knowledge of what instabilities lurk in the climate system and how they can influence life on Earth."

He said Nature did a similar experiment 635 million years ago, "and the outcome is preserved in the geologic record. We see that strong forcing on the climate, not unlike the current carbon dioxide forcing, results in the activation of latent controls in the climate system that, once initiated, change climate to a completely different state."

The research, detailed in the May 29 issue of the journal Nature, was supported by the National Science Foundation and NASA's Exobiology Program.

[americanophile]

Imagine the world covered in ice then rapidly warming without any SUVs. I don’t know whether there is significant climate change or global warming and if so, what causes it, but at least I admit it. These “experts” look at billions of years of natural history in which massive climate fluctuations occur (somewhat regularly), and then come to the conclusion that they understand the entire, immensely complex system, that we are the cause of said fluctuation, and that the scientific debate is over.

[TigersEye]

The globe is not encased in ice and there are no methane ice sheets now anywhere. Where is the comparison?

[JustDoItAlways]

During this period, almost all of the landmasses on Earth were locked together over the South Pole. Think Antarctica times 20.

The icesheets built up all the pole, spread out, reflected sunlight, grew bigger and so on and so on. The glaciers spread out so far that entire Earth cooled enough so that the oceans even froze except for the tropics probably.

Then continental drift starting splitting up the landmasses, they moved away from the Pole and viola, Snowball Earth over.

Continental drift explains these climate fluctuations throughout deep history far better than the global warming model.

This illustration is from the Carboniferous ice period 300 million years ago, but the principle is the same. 600 million years ago, basically all the continents were locked together in this configuration.

[steelyourfaith]

 

Beam me to Planet Gore !

[Alas Babylon!]

"Today we're conducting a global-scale experiment with Earth's climate system," Kennedy said, "and witnessing an unprecedented rate of warming, all with little or no knowledge of what instabilities lurk in the climate system and how they can influence life on Earth."

Main Entry: un·prec·e·dent·ed
Pronunciation: "&n-'pre-s&-"den-t&d
Function: adjective
Date: 1623
: having no precedent : NOVEL, UNEXAMPLED
- un·prec·e·dent·ed·ly adverb

We've gone ONE DEGREE C since 1860...

Someone PLEASE tell me how in the hell that is UNPRECEDENTED?

File under: Global Warming Lies & Hysteria!

[SunkenCiv]

Note: this topic is from 5/28/2008. Thanks NormsRevenge.

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