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  (Source: Travelvivi)
But scientists say it did not contribute to global warming today

Lawrence Livermore National Laboratory (LLNL) scientist, along with his team, recently used radiocarbon dating to trace carbon dioxide released to the atmosphere from the deep ocean at the end of the last ice age.

Radiocarbon dating employs the use of radioisotope carbon-14 to figure out the age of ancient and prehistoric carbonaceous materials. This process can be used on materials as old as 62,000 years old. 

Tom Guilderson, a scientist at the LLNL's Center for Accelerator Mass Spectrometry and an author of the study, found that an increase in atmospheric CO2 concentrations corresponded with a decreased amount of carbon-14 relative to carbon-12 in the atmosphere. 

"This suggests that there was a release of very 'old' or low 14/12CO2 from the deep ocean to the atmosphere during the end of the last ice age," said Guilderson. He noted that CO2 release may increase the rate at which ice melts after an ice age. 

Ocean circulation regulates radiocarbon in the atmosphere, and in turn, this regulates the sequestration of carbon dioxide in the deep ocean by atmosphere-ocean carbon exchange. Around 110,000 to 10,000 years ago when the last ice age occurred, lower atmospheric carbon dioxide levels coincided with increased atmospheric radiocarbon concentrations, which have been "credited to great storage of CO2 in a poorly ventilated abyssal ocean." The circulation of the ocean was drastically different back then, and Guilderson admits that he and his team do not fully understand the manner in which carbon was stored in deep ocean at that time. 

The team dated two sediment cores from the subtropic South Pacific near New Zealand and the sub-Antarctic to be approximately 13,000 and 19,000 years old. Guilderson was able to determine when the large CO2 release occurred using the carbon-14 in the cores. Also, he was able to determine the ocean pathway by which it escaped. 

"In this case, the absence of a signal is telling us something important," said Guilderson. "Deeper waters substantially depleted in carbon-14 were drawn to the upper layers and this is the main source of the CO2 during deglaciation. Data suggests that the upwelling of this water occurred in the Southern Ocean, near Antarctica. In our cores off New Zealand, which lie in the path of waters which 'turn over' in the Southern Ocean, we don't find anomalously low carbon-14/12 ratios.

"This implies that either water which upwelled in the Southern Ocean, after 16,500 years ago, had a vigorous exchange with the atmosphere, allowing its 14C-clock to be reset, or the circulation was significantly different than what the current paradigm is. If the paradigm is wrong, then during the glacial and deglaciation, the North Pacific is much more important than we give it credit for."

This carbon dioxide release sped up the melting, but when asked about CO2's contribution to

global warming today, Guilderson said this release of CO2 from the last ice age "is not relevant." But he did mention that he has used radiocarbon dating on CO2 in the atmosphere today, and that isotopic signature shows that use of fossil fuels is what is causing global warming. 

The study was published in the August 26 edition of Nature



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RE: Slow news day
By the3monkies on 8/30/2010 1:21:17 PM , Rating: 4
I'm a very wealthy guy - inherited most of my money - so naturally I'm a Republican. That's because the core concern of the powers behind my party has always been 'more money for me' - me, of course, meaning 'the mega rich'. Now we realize that the lower classes aren't going to get all pumped up to vote Republican if we come out and tell them we don't give a sh*t about anybody but the rich; so we keep the political spot-light on gay marriage, abortion, the Bible and that cute little Baby Jesus, freedom, guns, patriotism, and the uppity coloreds - all the things we've hoodwinked small-town America into believing are central to its well being.

Obviously, we don't give a rat's ass about any of these issues. My homes and townhouses are guarded and my kids go to exclusive prep schools where brain-dead nonsense like creationism is definitely not on the curriculum. But the end justifies the means, and if dumbing down the message is what it takes to get Joe Sixpack to vote the very candidates into office who work tirelessly to make it increasingly difficult for the average guy to have a decent life, so be it. (thumbs up smiley)

I mean, these people are hopeless anyway; remember this is a country where half the population thinks Jesus is coming back sometime in the next 50 years to smite the sinners and carry the righteous white folk off to heaven. The poor should consider themselves lucky to get the trickle-down slops we toss their way. Isn't the fact they're not rich proof that they're inferior?

So while our hired-guns in Congress work to lower income taxes for the top tenth of a percent of Americans who already own everything, strive to do away with odious inheritance taxes, and fight raising the minimum wage for the coloreds and white trash - we need guys like Glenn and Rush to blow smoke in the eyes of the dumb and gullible so that John Q doesn't catch on that he's being butt-f****d by the very people he votes for.

Thank Jesus I'm a billionaire!


RE: Slow news day
By SPOOFE on 8/30/2010 3:04:15 PM , Rating: 2
quote:
remember this is a country where half the population thinks Jesus is coming back sometime in the next 50 years to smite the sinners and carry the righteous white folk off to heaven.

Uh-huh, because non-white folk have no religious affiliation whatsoever. Hey, did you know Proposition 8 passed in California thanks to Latinos?

quote:
The poor should consider themselves lucky to get the trickle-down slops we toss their way. Isn't the fact they're not rich proof that they're inferior?

80% of the millionaires in this country are first-generation rich. The fact is that there is NO magic ceiling preventing virtually anyone from "making it"... it is simply a matter of most people being incapable of doing it.


RE: Slow news day
By mcnabney on 8/30/2010 7:02:57 PM , Rating: 2
That 80% stat is highly skewed due to real estate impacts, rapid population growth in the 20th century, and most importantly - inflation. If I sold my house and liquidated all of my assets I would probably be a millionaire too. It really isn't that much money.


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