Abstract :
The potential effects of CO2 emissions from fossil fuel energy production, large industries and changes in land use on climate change is an area of research requiring and receiving massive global efforts. Possible impacts of climate change and variability on marine life have received some attention, mainly regarding changes in living conditions via changes in water temperature, wind and waves and other physical climate related forcing of the marine environment. There is also a chemical forcing of the marine environment caused by CO2 emissions to the atmosphere penetrating into the oceans. The perturbation of the marine environment through such indirect, i.e. via the atmosphere, storage of CO2 in the oceans may be estimated based on known and predicted atmospheric CO2 levels. Capture of CO2 from the flue gas of power plants and large industries followed by storage directly in the oceans may be a necessary component of a greenhouse gas mitigation strategy for the next century in order to achieve a stabilization of atmospheric CO2 levels. Direct storage of CO2 in the oceans may impose, at least locally, a stronger perturbation of the marine environment than indirect storage via the atmosphere. Storage of waste CO2 in aquifers below the seabed may also affect the marine environment if CO2 leaks out in the water column above. In view of the perturbations of the marine environment that are already ongoing as a consequence of CO2 emissions to the atmosphere and which will accelerate in the business-as-usual scenario as well as in scenarios including realistic CO2 removal options, there is a need to clarify the resilience of marine ecosystems to increased CO2. This paper discusses the large perturbations that are expected in various scenarios. One hypothesis is that direct ocean storage if performed in the most environment-friendly way may be acceptable, while continued emissions to the atmosphere and invasion across the air-sea-interface could lead not only to climate change but could also be harmful to marine food webs and ecosystem functions. Some experimental approaches that may be taken in order to contribute to a wider knowledge base for CO2 policies are briefly described.
