Reuters release…

Oceans absorbing less CO2 may have 1,500 year impact
Wed Apr 16, 2008 7:06pm BST

By Sylvia Westall

VIENNA (Reuters) - Global oceans are soaking up less carbon dioxide, a development that could speed up the greenhouse effect and have an impact for the next 1,500 years, scientists said on Wednesday.

Research from a five-year project funded by the European Union showed the North Atlantic, which along with the Antarctic is of the world’s two vital ocean carbon sinks, is absorbing only half the amount of CO2 that it did in the mid-1990s.

Using recent detailed data, scientists said the amount absorbed is also fluctuating each year, making it hard to predict how and whether the trend will continue and if oceans will be able to perform their vital balancing act in the future.

Oceans soak up around a quarter of annual CO2 emissions, but should they fail to do so in the future the gas would stay in the atmosphere and could accelerate the greenhouse effect, a prospect project director Christoph Heinze called “alarming”.

Oceans are like a “slow-mixing machine”. Carbon absorbed in the North Atlantic takes around 1,500 years to circulate around the world’s seas. This means changes to their fragile balance could be felt long into the future, Heinze said at a geoscience conference in Vienna.

Scientists are still debating the reasons why oceans are absorbing less carbon dioxide. While some point to CO2 saturation, others say it could be caused by a change in surface water circulation, triggered by changes in weather cycles.

Heinze described a “bottleneck effect” because of the large amount of manmade carbon dioxide oceans already store.

“The more CO2 the oceans store, the more difficult it will be for them to take up the additional load from the atmosphere and carbon absorption will stagnate even further,” Heinze said.

Some forms of sea life have suffered from the large amounts of CO2 absorbed, because of changes in acidity levels.

“The seafloor is becoming an increasingly hostile environment,” said Marion Gehlen, from the Laboratory of Climate and Environment Science in France.

“This corrosive water means mollusc organisms have a hard time making their shells and eventually they might not be able to do it at all.”

For the scientists there is only one thing humans can do to resolve the problem — reduce emissions by at least 75 percent.

“We must act now. The good news is that while the negative effects can last a long time, the good things we do will also have an effect for the next 1,500 years,” Heinze said.

“It’s cheap and it’s possible to do this but people must have the will to do it.”

(Editing by Mary Gabriel)

PDF of press release here.
“CARBOOCEAN: How much man-made CO2 can the ocean absorb?”

Categories: Ocean Fertilization
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The UNESCO Intergovernmental Oceanographic Commission recently formed an ad-hoc Consultative Group on Ocean Fertilization in part for the purpose of addressing several scientific questions posed by the International Maritime Organization (IMO) London Convention Scientific Group.  Participating were Ken Caldeira, Scott Doney, Ulf Riebesell, Andrew Watson, Phil Boyd, Chris Sabine, Scott Barrett and others.  They have released a statement in advance of the IMO LC SG working session in Guayaquil, Ecuador in May.

Addressed in the statement were three principle questions:

• What constitutes “large scale” in the ocean?
• Is there justification of the need for experiments at scales of order 200km by 200km?
• What is the assessment of the impacts on oceans of experiments at such scales?

A few quotes:

“There is no well-established meaning to “large scale” that would allow it to usefully distinguish between activities that would and activities that would not damage the ocean environment”

“The effects on the fertilized patch of stirring and mixing with water that has not received the fertilization treatment becomes less important near the center of the patch as patch size increases. This would provide incentive to develop experiments at scales of order 200 km by 200 km, this scale being larger than that of typical ocean eddies. For the same reason, it may be easier to assess the influence of surface manipulations on the sinking fluxes of particles when the experiments are at this scale.”

“It is impossible to assess the impacts of experiments through information on spatial scale alone. A host of factors, including rates, amounts, concentration, duration and composition of chemical addition, location, time of year, and so on, could all jointly be determinative of ocean impacts.”

The complete statement is available here. 

Categories: Ocean Fertilization
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