Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:


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

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.


'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 in Nature Geoscience

Hannah Johnson | EurekAlert!
Further information:

More articles from Earth Sciences:

nachricht Wandering greenhouse gas
16.03.2018 | Alfred-Wegener-Institut, Helmholtz-Zentrum für Polar- und Meeresforschung

nachricht Unique Insights into the Antarctic Ice Shelf System
14.03.2018 | Alfred-Wegener-Institut, Helmholtz-Zentrum für Polar- und Meeresforschung

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Locomotion control with photopigments

Researchers from Göttingen University discover additional function of opsins

Animal photoreceptors capture light with photopigments. Researchers from the University of Göttingen have now discovered that these photopigments fulfill an...

Im Focus: Surveying the Arctic: Tracking down carbon particles

Researchers embark on aerial campaign over Northeast Greenland

On 15 March, the AWI research aeroplane Polar 5 will depart for Greenland. Concentrating on the furthest northeast region of the island, an international team...

Im Focus: Unique Insights into the Antarctic Ice Shelf System

Data collected on ocean-ice interactions in the little-researched regions of the far south

The world’s second-largest ice shelf was the destination for a Polarstern expedition that ended in Punta Arenas, Chile on 14th March 2018. Oceanographers from...

Im Focus: ILA 2018: Laser alternative to hexavalent chromium coating

At the 2018 ILA Berlin Air Show from April 25–29, the Fraunhofer Institute for Laser Technology ILT is showcasing extreme high-speed Laser Material Deposition (EHLA): A video documents how for metal components that are highly loaded, EHLA has already proved itself as an alternative to hard chrome plating, which is now allowed only under special conditions.

When the EU restricted the use of hexavalent chromium compounds to special applications requiring authorization, the move prompted a rethink in the surface...

Im Focus: Radar for navigation support from autonomous flying drones

At the ILA Berlin, hall 4, booth 202, Fraunhofer FHR will present two radar sensors for navigation support of drones. The sensors are valuable components in the implementation of autonomous flying drones: they function as obstacle detectors to prevent collisions. Radar sensors also operate reliably in restricted visibility, e.g. in foggy or dusty conditions. Due to their ability to measure distances with high precision, the radar sensors can also be used as altimeters when other sources of information such as barometers or GPS are not available or cannot operate optimally.

Drones play an increasingly important role in the area of logistics and services. Well-known logistic companies place great hope in these compact, aerial...

All Focus news of the innovation-report >>>



Industry & Economy
Event News

Ultrafast Wireless and Chip Design at the DATE Conference in Dresden

16.03.2018 | Event News

International Tinnitus Conference of the Tinnitus Research Initiative in Regensburg

13.03.2018 | Event News

International Virtual Reality Conference “IEEE VR 2018” comes to Reutlingen, Germany

08.03.2018 | Event News

Latest News

Wandering greenhouse gas

16.03.2018 | Earth Sciences

'Frequency combs' ID chemicals within the mid-infrared spectral region

16.03.2018 | Physics and Astronomy

Biologists unravel another mystery of what makes DNA go 'loopy'

16.03.2018 | Life Sciences

Science & Research
Overview of more VideoLinks >>>