CO2 removal by alkalinity enhancement: potential, benefits and risks

The research consortia RETAKE will assess the potential, feasibility and side effects of various forms of marine alkalinity enhancement (AE) as a means to reliably and sustainably remove CO2 from the atmosphere. Increased ocean alkalinity reduces the activity of CO2 in seawater, and prompts an enhanced flux of CO2 from the atmosphere into the ocean, thereby reducing the atmospheric CO2 concentrations. REATKE will examine a range of mineral alkalinity sources with respect to dissolution kinetics, CO2 sequestration potential and side effects on chemistry and biology.

Laboratory studies and mesocosm experiments of AE in benthic and pelagic systems will simulate realistic environments with focus on the Baltic and the North Sea. A hierarchy of numerical models will be used to simulate deployment in German coastal waters and elsewhere, and to extrapolate experimental results from local to regional and global scales. Permanence and accounting of carbon storage as well as monitoring, detection and attribution issues will be examined against the background natural variability. An investigation of economic aspects and the relation to the U.N. sustainability goals will complete the comprehensive assessment in order to inform policymakers about the feasibility, overall sequestration potential and environmental risks of ocean alkalinity enhancement.

Structure of the RETAKE network


GEOMAR Helmholtz Centre for Ocean Research Kiel

Prof. Dr. Andreas Oschlies (Coordinator) // Prof. Dr. Ulf Riebesell // Dr. David Keller // Dr. Sonja Geilert // Dr. Laura Haffert


Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research (AWI)

Prof. Dr. Jelle Bijma // Prof. Dr. Sabine Kasten // Prof. Dr. Maarten Boersma // Dr. Judith Hauck


Helmholtz-Zentrum hereon

Prof. Dr. Corinna Schrum // Dr. Moritz Mathis // Dr. Johannes Pein // Dr. Ute Daewel // Dr. Daniel Pröfrock // Dr. Tristan Zimmermann // Prof. Dr. Helmuth Thomas


Leibniz Institute for Baltic Sea Research Warnemünde (IOW)

Dr. Hagen Radtke // Prof. Dr. Gregor Rehder // Dr. Barbara Hentzsch // Dr. Steffen Bock


Kiel Institute for the World Economy (IfW)

Dr. Wilfried Rickel


Leibniz Centre for Tropical Marine Research (ZMT)

Prof. Dr. Nils Moosdorf


Potsdam Institute for Climate Impact Research (PIK)

Dr. Jessica Strefler


University of Bremen // MARUM // IUP

Prof. Dr. Wolfgang Bach // Prof. Dr. Monika Rhein // Dr. Reiner Steinfeldt


Universität Hamburg

Prof. Dr. Jens Hartman


Kiel University (CAU)

Prof. Dr. Marie-Catherine Riekhof // Dr. Rüdiger Voss // Dr. Hans Sloterdijk

Sponsored by the German Federal Ministry of Education and Research