The ocean absorbs a great amount of carbon dioxide from the air and is the carbon sink with the greatest capacity. This slows down atmospheric changes and the effect of the ocean on climate change is correspondingly great.
As a result of the important role of the ocean in the world-wide carbon cycle the question arises, whether the natural carbon absorption of the ocean can be accelerated by the additional introduction of carbon dioxide in the deep sea or below the surface of the sea.
Recent studies show, that storage of liquid CO₂ in the ocean could prove an alternative to the reduction of carbon in the world-wide cycle. Certain structures in the sea floor, e.g. water conducting strata or earlier deposit sites of fossil energy, appear promising for carbon injection.

Ecological Consequences:
Up to now the effects of carbon injection in sediment strata of the sea floor are not well known. The highly compressed CO₂ can alter the geophysical characteristics of the sediments.

• The liquefaction or the fixation of pH-sensitive ecologically relevant compounds
• Formation and stability of CO₂ hydrates in sea water and (sub)sediment in the relevant temperature and pressure range
• Accumulation of CO₂ hydrates and their effects on the permeability of the reservoir
• Changes in the acoustic velocity and in geo-electric characteristics

Without detailed knowledge about these processes the ecological effects of the proposed marine carbon dioxide disposal cannot be adequately estimated. The possible effects should be examined not only theoretically but also through experiments.

Economic and legal consequences:
From an economic standpoint the most important question is how much CO₂ injection will cost in comparison to other climate protection measures. Furthermore, the question arises of how carbon storage can be integrated into an efficient and effective complete carbon cycle management system. Only when the contribution of carbon binding in a carbon management system has been determined, should the use of appropriate political measures and the introduction of incentives for carbon storage be examined. Various types of political instruments could be used to create such incentives. The definition of these instruments is an especially ambitious research goal, since the oceans are not regulated by the legislation of individual countries but rather by international law. From a legal point of view it is still not clear, how CO₂ injection in international waters can be reconciled with currently valid international law. In addition, the mechanisms that can be used to offset costs and benefits to create incentives for countries and private companies to get involved in carbon storage still need to be clarified. 

Contact

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• Prof. Bernd Hartke

  Institution:

  Institut für Physikalische Chemie

  Phone:

  +49 431 880-2753

  E-mail:

  hartke@phc.uni-kiel.de

• Prof. Arne Körtzinger

  Institution:

  GEOMAR | Helmholtz-Zentrum für Ozeanforschung Kiel

  Phone:

  +49 431 600-4205

  E-mail:

  akoertzinger@geomar.de