Climate swings have brought great CO2 pulses up from the deep sea

[C1ay]

A study released today provides some of the first solid evidence that warming-induced changes in ocean circulation at the end of the last Ice Age caused vast quantities of ancient carbon dioxide to belch from the deep sea into the atmosphere.

 

Scientists believe the carbon dioxide (CO2) releases helped propel the world into further warming. The study, done by researchers at the University of Colorado, Kent State University and Columbia University's Lamont-Doherty Earth Observatory, appears in the May 10 advance online version of the leading journal Science.

 

Atmospheric CO2, also produced by burning of fossil fuels, is thought to be largely responsible for current warming. However, scientists have known for some time that the gas also goes through natural cycles. By far most of the world's mobile carbon is stored in the oceans-40 trillion metric tons, or 15 times more than in air, soil and water combined. But how this vast marine reservoir interacts with the atmosphere has been a subject of debate for the last 25 years. The study indicates what many scientists have long suspected, but could not prove: sometimes the oceans can release massive amounts of CO2 into the air as they overturn. "The lesson is that abrupt changes in ocean circulation in the past have affected the oceans' ability to keep carbon dioxide out of the atmosphere," said geologist Thomas Marchitto of the University of Colorado, a co-lead author. "This could help us understand how that ability might be affected by future global warming."

 

The researchers found the evidence in a core of Pacific Ocean sediment brought up from 705 meters--about 2,300 feet-off the coast of Baja California, Mexico. The core held the remains of bottom-dwelling protozoa called foraminifera, which take up carbon from surrounding water and use it to build their shells. The isotope carbon 14-normally used to date organic remains such as wood and bones-can also be used to date the water in which the foraminifera grew. Going back through layers built up over the past 38,000 years, the researchers found the shells contained expected levels of C14 in all but two brief periods, beginning roughly 18,000 years and 13,000 years ago. That meant the protozoa were using older sources of carbon, long isolated from the atmosphere. The carbon could come from only one place: upwelling of the deep sea, from depths of 3 kilometers (nearly two miles) or more. The researchers believe the water came not from the Pacific, but from the faraway Antarctic Ocean--the only part of the world where great upwelling can occur, due to the bottom topography and wind patterns. Most of the rising C02 probably poured out into the air in southern latitudes, but some carbon-rich water traveled on currents at intermediate depths to the north, where the foraminifera recorded its C14 signature.

 

The upwelling and release of this carbon dioxide matches well with rapid warming and rises in atmospheric CO2 shown in glacial ice cores from Antarctica and other far-flung records. The researchers believe that largely as a result of these episodes, CO2 in the atmosphere went from 190 parts per million (ppm) during glacial times to about 270 ppm, and remained at that level until recently. A similar but much more rapid rise, to 380 ppm, has taken place since the Industrial Revolution-most of it in the last few decades. Both rises almost certainly stoked climate warming.

 

Exactly what caused the upwelling is not clear, but many scientists believe the world was already undergoing a natural warming cycle, possibly due to a slight periodic change in earth's orbit. This suddenly ended the last Ice Age, in turn changing ocean currents and wind patterns. The hypothesis favored by paper's authors is that sudden disintegration of northern ice sheets during this initial warming slowed or halted deep Atlantic Ocean circulation. This in turn warmed the Antarctic, causing massive retreats of sea ice and allowing deep Antarctic waters to surface. Thus, it is possible that the signal detected in the Pacific ultimately originated on the other side of the world.

 

"Once the CO2 started rising, it probably helped the warming process along-but exactly how much, we can't say," said Robert Anderson, a Lamont-Doherty expert in ocean circulation who was not involved in the study. "And there is still huge uncertainty as to how the oceans will respond to current warming." Anderson says the study should be a wake-up call to the scientific community to expand studies of the oceans' relationship to climate change.

 

Source: The Earth Institute at Columbia University

[Pangolin]

Here in California we like a healthy upwelling because the nutrients fire off phytoplankton that feed the edible fish species. Also one of the claimed advantages of OTEC, ocean-thermal, power plants is that they bring nutrients to the surface resulting in localized increases in fish populations.

 

Now this article says upwelling could be bad but provides no info on what the balance of the effects are. :P

 

Anybody got a clue?

[Eilizsia]

All You Have to Do Is Filter the Carbon, The same way Moisture does in the atmosphere, Causing acid rain. But If you Use Moistured Filter In car exausts The Carbon Will Attach to the Water and just leak at the end of the exaust pipe. If It is done, An if a constant circulation keeks all the filter wet, then the smake will just pass through over and over again. That will stop carbon to go into the atmosphere, Copy what acid rain does but on the groung.

[CraigD]

Now this article says upwelling could be bad but provides no info on what the balance of the effects are. :xparty:

The effect suggested by the article is that such ocean upwellings resulted in large amounts of disolved CO2 being released into the atmosphere. At the end of an ice age, when the Colorado, Kent State and Columbia researchers suggest this last happened, such a release was not “bad”, as the resulting increase in global temperature made Earth more hospitable to our sort of life. If it were to happen now, it would be bad, as the resulting increase in global temperature would cause flooding, agricultural problems, and other disruptions to human civilization.

All You Have to Do Is Filter the Carbon, The same way Moisture does in the atmosphere, Causing acid rain.

Because Acid rain removes primarily SO2 and nitrogen oxides, not CO2, from the air, this wouldn’t be an effective way to remove CO2. To remove CO2, something like a CO2 scrubber (or, simpler, a plant) is needed.

[Zythryn]

Very interesting, and it seems to nicely fit the observed data.

I very much agree with the call for even more research into the role of the oceans in the carbon cycle/GW.

If the hypothesis/theory is correct, we should be able to duplicate the results in othere areas of the ocean. The results may be even more clear and give us a better idea as to what happened if we try this study in more southern regions of the ocean.