What we do

The consortium RETAKE generates practical knowledge on the feasibility, potentials, and risks of marine alkalinity enhancement (AE). Our motivation is to test the hypothesis that increasing alkalinity in seawater can lead to increased CO2 uptake from the atmosphere in an ecologically sound manner. AE is accomplished by introducing appropriate minerals that provide a source of alkalinity by dissolving in seawater (e.g., carbonate and silicate rocks) and altering the chemistry of seawater.

Different approaches and research methods will be used:

  • laboratory experiments, mesocosm (water column) and benthocosm (seabed) studies examine the underlying mechanisms and effects of alkalinity enhancement under idealised laboratory conditions on the one hand and under natural conditions in closed experimental setups on the other hand
    –> Topic: Mechanisms
  • observational studies quantify the natural variability of alkalinity and form the basis for the development of balancing and monitoring methods
    –> Topic: Observation & Monitoring
  • numerical models simulate alkalinity enhancement and extrapolate experimental results to larger spatial and temporal scales
    –> Topic: Extrapolation through Models
  • socio-economic studies assess the potential of CO2 removal in relation to global climate policies, net-zero greenhouse gas targets, the UN Sustainable Development Goals (SDGs), aa well as food security and fisheries development
    –> Topic: Social Sciences and Economics

How does alkalinity enhancement work?

The weathering of rocks is a natural process in which CO2, which is constantly being released into the atmosphere through geological processes (e.g. volcanic eruptions), is removed again. While this process has ensured that the Earth’s climate has remained relatively stable over the past billions of years, the anthropogenic CO2 input is about a hundred times too fast to be compensated by natural weathering.
The RETAKE project will investigate the extent to which rock weathering and subsequent storage of carbon in the form of stable bicarbonate or carbonate ions in seawater can be accelerated by the additional input of suitable rocks, thereby removing some of the anthropogenically produced CO2 from the atmosphere again in the long term.