Carbon sequestration: Boon or burden

Jun 27, 2010
Calculations show that storing CO2 in deep sea would cause serious problems for life in deep seas, and in addition, CO2 will rather quickly find its way back into the atmosphere.

The idea to sequester carbon is gaining support as a way to avoid global warming. For example, the European Union plans to invest billions of Euros within the next ten years to develop carbon capture and storage whereby CO2 will be extracted at power plants and other combustion sites and stored underground. But how effective is this procedure and what are the long-term consequences of leakage for the oceans and climate? A Niels Bohr Institute researcher has now cast light upon these issues. This research has just been published in the scientific journal, Nature Geoscience.

Large scale use of carbon sequestration could help to avoid extreme global warming that would otherwise occur in the near future unless are reduced significantly. But it is not clear how effective different types of sequestration are in the long run, owing to leakage of stored CO2 back out to the atmosphere. Nor is it clear what would be the long-term consequences of such leakage for the Earth's environment.

Gary Shaffer, professor at the Niels Bohr Institute, and leader of the Danish Center for Earth System Science, made long model projections for a number of sequestration/leakage scenarios. His results show that leakage of the stored CO2 may bring about large atmosphere warming, large sea level rise and , and elevated CO2 concentrations in the ocean.

Storage of CO2 in the is a poor choice since this creates grave problems for deep sea life and since CO2 stored this way returns to the atmosphere relatively quickly, bringing back the global warming.

Geological storage may be more effective in delaying the return of the warming and associated consequences but only if a CO2 leakage of 1 % or less per thousand years can be obtained.

Carbon sequestration: Boon or burden
CO2 storage underground may be more effective but only if we can achieve minimal leakage of 1 percent or less for each millennium.

A burden for future society

Alternatively, one could actively counter leakage from the ocean or geological reservoirs by re-sequestering CO2 to stabilize climate at some desired level. But it would be hard to gauge the global leakage rate to be matched by re-sequestration. Furthermore, re-sequestration would have to be carried out over many thousands of years, a burden for future society in line with that of long term management of nuclear waste.

"CO2 sequestration has many potential advantages over other forms of climate geoengineering. It makes good sense to modify the Earth's radiation balance by putting carbon back in where it came from. Atmospheric CO2 is long-lived and evenly-distributed globally making it possible to manage it in a long-term, controlled way with less chance for unpleasant climate surprises. However, one should not underestimate potential short and long-term problems with leakage from underground reservoirs. Carbon in light form will seek its way out of the ground or seabed. The present situation in the Gulf of Mexico is a poignant reminder of that", says Gary Shaffer.

Professor Shaffer concludes that "the dangers of carbon sequestration are real and the development of this technique should not be used as an argument for continued high fossil fuel emissions. On the contrary, we should greatly limit CO2 emissions in our time to reduce the need for massive and thus reduce unwanted consequences and burdens over many future generations from the leakage of sequestered CO2."

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Provided by University of Copenhagen

3.8 /5 (16 votes)

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User comments : 12

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vivcollins
2.5 / 5 (4) Jun 27, 2010
Why throw away the Co2? why is it not considered a valuable feedstock for other processes?

Is it just an attitude problem? Give a lump of coal to a combustion expert and they see it as heat and flue gas, the same lump of coal to a chemical engineer is a bewildering array of useful chemical products
Corban
4.4 / 5 (8) Jun 27, 2010
Plant trees. Here's why:

1. Tree bark is atmosphere + sunlight, not dirt + sunlight. Good CO2 binding!
2. Existence of giant sequoias establishes that CO2 can be reliably sealed for hundreds of years.
3. Practically grows itself without maintenance
4. Photosynthesis is very efficient

Why people are looking to novel technological solutions is beyond me. Maybe it's because you can't trademark trees?
Shootist
1.8 / 5 (4) Jun 27, 2010
Plant trees. Here's why:

1. Tree bark is atmosphere + sunlight, not dirt + sunlight. Good CO2 binding!
2. Existence of giant sequoias establishes that CO2 can be reliably sealed for hundreds of years.
3. Practically grows itself without maintenance
4. Photosynthesis is very efficient

Why people are looking to novel technological solutions is beyond me. Maybe it's because you can't trademark trees?


Channeling Freeman Dyson?
omatumr
2.5 / 5 (8) Jun 27, 2010
Plant trees. Here's why:

1. Tree bark is atmosphere + sunlight, not dirt + sunlight. Good CO2 binding!
2. Existence of giant sequoias establishes that CO2 can be reliably sealed for hundreds of years.
3. Practically grows itself without maintenance
4. Photosynthesis is very efficient

Why people are looking to novel technological solutions is beyond me. Maybe it's because you can't trademark trees?


"More Research Grants" is the name of the game.

Carbon sequestration is a boondoggle - a scheme that wastes time and money.

With kind regards,
Oliver K. Manuel
Former NASA Principal
Investigator for Apollo

mrlewish
4 / 5 (4) Jun 28, 2010
Remember the movies War Games? The only way to win is not to play the game.

The solution to carbon sequestration is not to produce it of have to produce it in the first place. The solution has been know for thousands of years. It's called birth control and female education and economic empowerment. Wouldn't this world be quite nice if there were only a billion of us?
Parsec
5 / 5 (5) Jun 28, 2010
Sequesterization inside some mineral types cause chemical combination of the CO2 with the mineral. This means that unless that mineral is subjected to volcanic or seduction events, the expected leakage rate would be MUCH lower that 1% per thousand years.

This is the mechanism in which vast quantities of ancient CO2 sequestered in carbonate deposits are stable even when exposed to millions of years of surface erosion and sedimentation.

Only people who know nothing about the subject would consider this to be a boondoggle. It may fail for a number of reasons, but the technological feasibility of the science is certainly viable.
JerryPark
1 / 5 (3) Jun 28, 2010
Foolishness, even with good intention, is never anything but foolish.

Chicken Little cannot prop up the sky -- and does not need to.
PPihkala
5 / 5 (2) Jun 28, 2010
The reason for venting CO2 to atmosphere is a) it is allowed and b) it's the cheapest way to get rid of that byproduct of burning fossil fuels. Until it is more accepted that this activity is not sustainable, it will continue. But we must stop it sooner or later. The later, the more we must also deal with more harmful consecuances of this pollution.
RealScience
5 / 5 (2) Jun 28, 2010
In addition to forming carbonate rocks, any well that has held natural gas for tens to hundreds of millions of year is a great bet for holding CO2.

And if it turns out that we need the CO2 to prevent the next ice age (or as a chemical feedstock), we can re-open the wells and extract the CO2 again.

Carbon sequestration may have economic challenges but not geologic challenges.
po6ert
1 / 5 (1) Jun 29, 2010
excesive carbon sequestration is one of the cause of global ice ages. luckily we are reversing the effect. If you are worried about global warming, try an ice age!
Choice
1 / 5 (1) Jun 30, 2010
Please see discourse by geochemist on fate of CO2 injected into subsurface reservoirs: http://160.36.161...91ec4da8
There remain many questions.

I fail to understand why CO2 conversion to (bi)carbonates followed by injection into ocean waters, as discussed by Calera and Rau, is ignored in all of these comparative discussions. It is as if the decision has already been made to implement solely end-of-pipe capture to geologic sequestration. Could this be yet another case of the oil/gas/drilling folks tilting the machine in their direction with research $$? I have nothing against this strategy but doubt its efficacy on the global scale, considering all the nations and variety of GHG sources involved. I posit that atmospheric capture followed by chemical transformation and (bi)carbonate sequestration is a necessary adjunct to flue capture plus underground burial. There are many strong arguments behind this statement. No room here to expand.
Hunnter
1 / 5 (1) Jul 04, 2010
Not too sure if i am a fan of preventing global climate change. We could well screw up Earth this time around instead of just screwing up the life on it.

Still, why ditch it at all? Carbon nanotubes. That is all.