Researchers find a 'great fizz' of carbon dioxide at the end of the last ice age

Aug 25, 2010
Rutgers oceanographer Elisabeth Sikes wrapping up core samples during a recent research voyage.

Imagine loosening the screw-top of a soda bottle and hearing the carbon dioxide begin to escape. Then imagine taking the cap off quickly, and seeing the beverage foam and fizz out of the bottle. Then, imagine the pressure equalizing and the beverage being ready to drink.

Rutgers marine scientist Elisabeth Sikes and her colleagues say that something very similar happened on a grand scale over a 1,000 year period after the end of the last ice age - or glaciation, as scientists call it.

According to a paper published recently in the journal Nature, the last ice age featured a decrease in the amount of and an increase in the atmospheric carbon 14, the isotope that guides scientists in evaluating the rate of decay of everything from shells to trees.

In recent years, other researchers have suggested that some of that carbon dioxide flowed back into the rather than being entirely released into the atmosphere in the .

Sikes and her colleagues disagree. Their data, taken from cores of pulled up from 600 meters to 1,200 meters below the South Pacific and Southern Ocean, suggest that this "de-gassing" was regional, not global. This has important implications for understanding what controls where and how CO2 comes out of the ocean, and how fast - or, to put it another way, what tightens or loosens the bottle cap.

Carbon dioxide and carbon 14 in the atmosphere and ocean are on opposite ends of an environmental pulley. When the level of carbon dioxide in the atmosphere increases, the level of carbon 14 drops, and vice versa. That's chemistry and . Biology also helps, because photosynthesizing organisms use carbon dioxide, then die and take it with them to the bottom. During the last ice age, the level of carbon dioxide in the atmosphere was lower because much of it was trapped in the bottom of the oceans.

The ventilation of the deep - the circulation of oxygen through the deep waters - slowed considerably during the last ice age, causing carbon dioxide to build up. Sikes and her co-authors report that, as the ice began to melt, the oceanic bottle cap began to loosen, and the carbon dioxide began to leak back into the atmosphere. Then, as warming intensified, the cap came off, and the carbon dioxide escaped so quickly, and so thoroughly, that Sikes and her colleagues could find very little trace of it in the they examined in their samples.

Eventually, just like the carbonated drink in a bottle, equilibrium was established between the carbon dioxide in the atmosphere and the carbon dioxide in the ocean. Today, the carbon dioxide level in the atmosphere has been rising in the past 200 years pushing the levels in the ocean up. Human activity is responsible for that rise and the rise of other "greenhouse gases." Some people have suggested we can pull carbon dioxide out of the and force it back down to the bottom of the oceans by manipulating the biology - growing algae, for instance, which would increase photosynthesis and send carbon dioxide to the bottom when the organisms die. But Sikes' results suggest that global warming could eventually result in another great fizz.

Explore further: NASA sees Genevieve squeezed between 3 tropical systems

More information: Paper: www.nature.com/nature/journal/… ull/nature09288.html

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thermodynamics
5 / 5 (6) Aug 25, 2010
I guess I am surprised the denialists have not pounced on this yet. The article says: "Today, the carbon dioxide level in the atmosphere has been rising in the past 200 years pushing the levels in the ocean up. Human activity is responsible for that rise and the rise of other "greenhouse gases."" The denialists will say:

1) How do you know that humans are responsible for the CO2 rise over the past 200 years?

2) The human contribution to CO2 is small with regard to the total CO2 flux.

3) This shows that CO2 follows warming not the other way around...

So, let me answer these preemptively.

1) We know that human activity is raising the CO2 levels because we can do a "mass balance." While not complete (we don't have a handle on all of the sources and sinks) we do have enough information to determine that the incremental contribution by humans have pushed the CO2 content up by the amount that is consistent with a chemical engineering mass balance. (continued)
thermodynamics
4.8 / 5 (6) Aug 25, 2010
Continued:

2) While the "wild" sources do outweigh the human sources, they were in near balance before we started burning fossil fuels and changing land use. It is the incremental change that is making the difference and causing the rise in CO2 content. It would be as though you were filling a bucket with a hole in it. If the amount going in is the same as the amount going out you are balanced. However, if you change the amount going in just a tiny bit you will start filling the bucket. This is independent of the amount of the major flows and can be very small with respect to those major flows. Our addition of CO2 is small but imbalances the major fluxes by the amount we are adding unnaturally.

3) Yes, in the past CO2 followed warming (as the conditions changed it came out of the sinks). Now we have changed the game by leading with CO2. The result is that we have "kick started" warming and feedback will add even more CO2 and H2O.

Let the denialists start screaming.
marjon
1 / 5 (5) Aug 25, 2010
"Their data, taken from cores of ocean sediment pulled up from 600 meters to 1,200 meters below the South Pacific and Southern Ocean, suggest that this "de-gassing" was regional, not global."

We are told that the CO2 levels monitored at Maui correlate with global levels.
Skeptic_Heretic
5 / 5 (4) Aug 25, 2010
We are told that the CO2 levels monitored at Maui correlate with global levels.
The top of Kilawea and the bottom of the Gulf of California are not the same, or even semi-similar places.
marjon
1 / 5 (4) Aug 25, 2010
We are told that the CO2 levels monitored at Maui correlate with global levels.
The top of Kilawea and the bottom of the Gulf of California are not the same, or even semi-similar places.

"degassing was regional"
"This has important implications for understanding what controls where and how CO2 comes out of the ocean, "
They certainly imply that CO2 levels in the atm across the globe have regional variability.
Skeptic_Heretic
5 / 5 (3) Aug 25, 2010
They certainly imply that CO2 levels in the atm across the globe have regional variability.
No they don't. degassing would be the action of releasing from aqueous solution, not the injection into the atmosphere. The injection into the atmosphere would rather readily and quickly be dispersed by wind currents.
thermodynamics
5 / 5 (3) Aug 25, 2010
There are two different issues here. There is, indeed, some local variation in CO2. For instance, measuring CO2 downwind from a power plant gives more CO2 than measuring CO2 over the middle of the ocean. However, that is transient and localized. As soon as you get any significant distance from CO2 sources it starts mixing. However, it is not perfect mixing even over thousands of miles. There are new satellites in orbit to measure this heterogeneity. Having said that it is a small and variable heterogeneity. The bulk of CO2 in the atmosphere is well mixed and any plume will mix over time. What I want to say here is that there is some heterogeneity but it does not have a global effect.

If we say there is none, marjon will jump all over it if he is smart enough to look up the new satellite mission statement. They are talking about identifying fluctuations around sources and sinks and not about the effect on global temperature (which will be small) and is for mass balance.
marjon
1 / 5 (2) Aug 25, 2010
not about the effect on global temperature (which will be small)

Jumping: small?
thermodynamics
5 / 5 (3) Aug 25, 2010
marjon: I am referring to the fluctuations probably having a small effect, not the CO2. I was sure you could find something to jump on and didn't want to disappoint you. Thanks for pointing out the lack of clarity.

While the effect is expected to be small on the global scale, understanding the local effects will be important for sensitivity analysis in the simulation software. For all I know, the sensitivity analysis will turn up something that does have a global effect. That is why they build the simulations.
marjon
1 / 5 (2) Aug 25, 2010
For all I know, the sensitivity analysis will turn up something that does have a global effect. That is why they build the simulations.

GIGO.
MatthiasF
5 / 5 (1) Aug 25, 2010
Imagine loosening the screw-top of a soda bottle and hearing the carbon dioxide begin to escape. Then imagine taking the cap off quickly, and seeing the beverage foam and fizz out of the bottle. Then, imagine the pressure equalizing and the beverage being ready to drink.


AND THE BEVERAGE TURNS TO DIAMONDS!

Jesus, that was a long winded paragraph.