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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 Jyrioffinland on 8/30/2010 11:34:43 AM , Rating: 0
"Common sense" has been used to justify, e.g., slavery. Without proper knowledge (i.e. science) it's just another name for guessing.


RE: Slow news day
By mdogs444 on 8/30/2010 11:56:00 AM , Rating: 2
At the time, it probably was common sense from certain peoples perspectives that slavery was good for the country. Financially for slave owners, they were probably right. Emotionally and morally it was wrong - that many years ago life was much different.

In a sense, this is polar opposite. Emotionally and morally, the environmental movement is trying to get back to back global warming - not by the scientific facts or lack there of, but out of the visuals of polar bears, dying animals, oil covered birds, etc. When shown the hockey stick graph and all of its controversial methods and the CRU emails - actual proven facts that people can see for themselves - the movement wouldn't go anywhere.

So in the end - common sense to you is believing in global warming - which as you just stated, is just another name for guessing.


RE: Slow news day
By Jyrioffinland on 8/30/2010 8:18:01 PM , Rating: 2
Let me give you another explanation so maybe you understand what I try to say.

Suddenly you get a major headache. What do you do?

Common sense tells a layman to take an aspirin or two and it should go away.

For someone with knowledge of medicine it's a sign you may have a brain hemorrhage and aspirin may cause you bleed to death. Skip aspirin, go to ER.

So you need also knowledge, not just common sense, to understand subjects like climate change or global warming.

quote:
common sense to you is believing in global warming


Whoa! Hold your horses, cowboy! Where did I say I believe in global warming? What do you even mean by that?

I don't "believe in global warming". I know some facts and I know there's a lot we don't know yet.

Only a fool would claim the globe has not warmed any in the last few decades. Also, only a fool would claim we're predestined to end up like burgers on a BBQ grill.

Only a fool would claim the climate is static, never-changing. Only a fool would claim humans have either absolutely none or all to do with the recent changes.

Only a fool would claim we are now capable of predicting certainly how it will change in the future. Only a fool would claim we never will.

I know the climate+oceans+humans-equation is basically a chaotic (non-linear) system and theoretically it can go any way from now on.

So only a fool would NOT acknowledge the possibility --- how ever small it may be --- that things may go wrong, maybe even horribly wrong.

There IS a slight chance this globe of ours is not going to be able to keep its cool endlessly, given what we throw at it. It's only good proactive thinking to take into account all possible scenarios when planning the future for us.

Moreover, personally I get frustrated with people who have no understanding whatsoever of science yet they keep disparaging perfectly legit scientists and research results.

It feels like if someone came up a new fine drug for cancer and everybody would just be dissing the scientist and some zealots would give advice for cancer patients to forget the drug but pray instead.

And all the rushlimbaughs on the AM hate radio would air special shows on how this anti-American God-hating commy-loving corrupted scientist actually did it just to make another top-seller for the baby-blood-drinking drug company big shots.


RE: Slow news day
By SPOOFE on 8/30/2010 3:06:53 PM , Rating: 2
quote:
"Common sense" has been used to justify, e.g., slavery. Without proper knowledge (i.e. science) it's just another name for guessing.

But WITH proper knowledge, it makes your "slavery" analogy look absolutely idiotic.


RE: Slow news day
By Jyrioffinland on 8/31/2010 4:53:18 AM , Rating: 2
quote:
But WITH proper knowledge, it makes your "slavery" analogy look absolutely idiotic


Yeah, right! And withOUT any rationale, your comment sounds absolutely idiotic.

Go back to your comic books, please.


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