Carbon cycling was much smaller during last ice age than in today's climate: study

Nov 20, 2011
Earth

Atmospheric carbon dioxide (CO2) is one of the most important greenhouse gases and the increase of its abundance in the atmosphere by fossil fuel burning is the main cause of future global warming. In past times, during the transition between an ice age and a warm period, atmospheric CO2 concentrations changed by some 100 parts per million (ppm) – from an ice age value of 180 ppm to about 280 ppm during warm periods.

Scientists can reconstruct these changes in the atmospheric carbon stock using direct measurements of atmospheric CO2 trapped in air bubbles in the depth of Antarctica's ice sheets. However explaining the cause of these 100ppm changes in atmospheric CO2 concentrations between glacial and interglacial climate states – as well as estimating the carbon stored on land and in the ocean – is far more difficult.

The researchers, led by Dr Philippe Ciais of the Laboratoire des Sciences du Climat et l'Environnement near Paris, ingeniously combined measurements of isotopes of atmospheric oxygen (18O) and carbon (13C) in marine sediments and ice cores with results from dynamic global vegetation models, the latter being driven by estimates of glacial climate using climate models.

Dr Marko Scholze of the University of Bristol's School of Earth Sciences, co-author on the paper said: "The difference between glacial and pre-industrial carbon stored in the terrestrial biosphere is only about 330 petagrams of carbon, which is much smaller than previously thought. The uptake of carbon by vegetation and soil, that is the terrestrial productivity during the ice age, was only about 40 petagrams of carbon per year and thus much smaller: roughly one third of present-day terrestrial productivity and roughly half of pre-industrial productivity."

From these results, the authors conclude that the cycling of carbon in the terrestrial biosphere – that is, the time between uptake by photosynthesis and release by decomposition of dead plant material – must have been much smaller than in the current, warmer climate.

Furthermore there must have been a much larger size of non-decomposable carbon on land during the Last Glacial Maximum (the period in the Earth's history when ice sheets were at their maximum extension, between 26,500 and 19,000 years ago).

The authors suggest that this inert carbon should have been buried in the permanently frozen soils and large amounts of peat of the northern tundra regions.

Explore further: Researchers prove for the first time that ash clouds can cross Atlantic Ocean

More information: 'Large inert carbon pool in the terrestrial biosphere during the Last Glacial Maximum' by P. Ciais, A. Tagliabue, M. Cuntz, L. Bopp, M. Scholze, G. Hoffmann, A. Lourantou, S. P. Harrison, I. C. Prentice, D. I. Kelley, C. Koven and S. L. Piao, Nature Geoscience, 2011.

Related Stories

Losing more than we gain from autumn warming in the north

Jan 02, 2008

An international study investigating the carbon sink capacity of northern terrestrial ecosystems discovered that the duration of the net carbon uptake period (CUP) has on average decreased due to warmer autumn temperatures.

Global warming: New study challenges carbon benchmark

Sep 28, 2011

The ability of forests, plants and soil to suck carbon dioxide (CO2) from the air has been under-estimated, according to a study on Wednesday that challenges a benchmark for calculating the greenhouse-gas ...

Ice core studies confirm accuracy of climate models

Sep 11, 2008

An analysis has been completed of the global carbon cycle and climate for a 70,000 year period in the most recent Ice Age, showing a remarkable correlation between carbon dioxide levels and surprisingly abrupt changes in ...

US rivers and streams saturated with carbon

Oct 17, 2011

Rivers and streams in the United States are releasing enough carbon into the atmosphere to fuel 3.4 million car trips to the moon, according to Yale researchers in Nature Geoscience. Their findings could ...

Recommended for you

Geologists discover ancient buried canyon in South Tibet

7 hours ago

A team of researchers from Caltech and the China Earthquake Administration has discovered an ancient, deep canyon buried along the Yarlung Tsangpo River in south Tibet, north of the eastern end of the Himalayas. ...

User comments : 14

Adjust slider to filter visible comments by rank

Display comments: newest first

StillWind
2 / 5 (16) Nov 20, 2011
Wow...it is inconceivable that people are stupid enough o believe this drivel.
omatumr
2 / 5 (16) Nov 20, 2011
Atmospheric carbon dioxide (CO2) is one of the most important greenhouse gases and the increase of its abundance in the atmosphere by fossil fuel burning is the main cause of future global warming.


In fact Earth's climate has always changed. Life evolves because Earth's heat source - the Sun - changes and continues to evolve.

http://judithcurr...t-140333

With kind regards,
Oliver K. Manuel
Former NASA Principal
Investigator for Apollo
http://myprofile....anuelo09
jsa09
4.3 / 5 (12) Nov 20, 2011
If your comments are in conflict with the researchers findings do you mind stating why and where the conflict arises. That quote above is not even from this article and stating that this is drivel without clarifying is pointless.
deatopmg
1.9 / 5 (20) Nov 20, 2011
@jsa09 This article is drivel because NO scientific relationship has yet been established, or even hints that the concentration of CO2 drives temperature of the earth, even though the warmistas and the other societal parasites would have you believe the science is settled. The earth may be warming but it's not CO2. Based on first principles and evidence it simply isn't. The models are simply that; faulty, incomplete models that fail to duplicate the past.

In addition, CO2 is only a minor GH gas. Water vapor is THE major GH gas and major temperature modulator.
unknownorgin
1.9 / 5 (8) Nov 21, 2011
The study shows that grand ideas of cutting CO2 levels could trigger another ice age according to the greenhouse gas theory.
Birger
3.9 / 5 (7) Nov 21, 2011
"Wow...it is inconceivable that people are stupid enough o believe this drivel."

Yes, all those problematic air bubbles trapped in the Antarctic ice are just a practical joke left by God when he created Earth 4004 BC. Just like all those dinosaur fossils (sarcasm).

If anyone says anything that challenges my beliefs, I will simply assume it is a global conspiracy, financed by the communtist-nazis and Opus Dei. With a bit of help from the Martians.

Anyway, who needs elitisty "scientific facts" and "truth" when "truthiness"* (my random assumptions and beliefs) is more comforting

[* a term invented by that great thinker and statesman G. W. Bush]
ED__269_
3 / 5 (4) Nov 21, 2011
@jsa09 This article is drivel because NO scientific relationship has yet been established, or even hints that the concentration of CO2 drives temperature of the earth, even though the warmistas and the other societal parasites would have you believe the science is settled.


The atmosphere does contributed to GW, that includes a CO2 factor(The sum of which is most likely better said through entropy). The dedicated scientist know that the science still needs tweaking... (dagnamit, I wanted to concentrate on other areas of physics, but that may have to change).

... In addition, CO2 is only a minor GH gas. Water vapor is THE major GH gas and major temperature modulator.


Again, this is probably better addressed via tracking relative changes in entropy.

Oliver is right in that the sun provides the energy which drives the earths temperature. However, changes to the earths equilibrium in the continuous capacity is the real issue. We can know this...
ShotmanMaslo
3.4 / 5 (5) Nov 21, 2011
In addition, CO2 is only a minor GH gas. Water vapor is THE major GH gas and major temperature modulator.


And your point is?

1. Humans do not directly alter the concentration of water vapour significantly, contrary to CO2

2. Water vapour increases the effect of CO2 by positive feedback
ED__269_
1 / 5 (4) Nov 21, 2011
We can know this because there is a third component to our heavenly equilibrium, the moon.

I'm sure, that after doing a comparative area accretion rate comparison between the earth and moon, that Oliver's underlying implied sun-changes can be correctly mitigated.
antialias_physorg
4.8 / 5 (5) Nov 21, 2011
This article is drivel because NO scientific relationship has yet been established, or even hints that the concentration of CO2 drives temperature of the earth

And you may notice that the article doesn't say a word about global warming or the connection of CO2 thereto.

Declaring something 'drivel' for something it doesn't state just shows that you have either not read the article or haven't understood it (and therefore are supremely unqualified to comment on it)
rubberman
3.7 / 5 (3) Nov 21, 2011
@AP
The article doesn't...but the commentary preceding the article does state a direct correlation to CO2 and future warming. Therefore we can sight an innate lack of intelligence as the reason deatopmg should not be commenting. GHG's trap heat in the atmosphere, CO2 has been proven to be a GHG, therefore the more of it there is, the less heat it will allow to escape. That is as simply put as i can make it, if you do not understand, go hang out at the FOX website with the rest of your IQ bracket.
ED__269_
1 / 5 (1) Nov 22, 2011
@AP
The article doesn't...but the commentary preceding the article does state a direct correlation to CO2 and future warming. Therefore we can sight an innate lack of intelligence as the reason deatopmg should not be commenting. GHG's trap heat in the atmosphere, CO2 has been proven to be a GHG, therefore the more of it there is, the less heat it will allow to escape. That is as simply put as i can make it, if you do not understand, go hang out at the FOX website with the rest of your IQ bracket.


It's not that simple.

there is around a 27 L per gram conversion for combusted fossil fuels.

Do the math just on the Worlds daily Global fossil fuel consumption, and do a volume analysis. Then answer the question

Where does all that volume go to? To help give you insight, ask "how come the earths atmosphere boundary doesn't keep expanding?"... "And how come the oceans are only at the present level of acidity?"

Explain the diffence
ED__269_
1 / 5 (1) Nov 22, 2011
It's not that simple.

there is around a 27 L per gram conversion for combusted fossil fuels.

Do the math just on the Worlds daily Global fossil fuel consumption, and do a volume analysis. Then answer the question

Where does all that volume go to? To help give you insight, ask "how come the earths atmosphere boundary doesn't keep expanding?"... "And how come the oceans are only at the present level of acidity?"

Explain the difference
***edit***
ED__269_
1 / 5 (1) Nov 22, 2011
Anyway,

The science I want to concentrate is not GW. There is no solution in GW. So, I leave it here, to be most likely mitigated.

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.