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Antonio Navarra - One of the best experts on this subject based on the ideXlab platform.
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global and regional Ocean carbon uptake and climate change sensitivity to a substantial mitigation scenario
Climate Dynamics, 2011Co-Authors: Marcello Vichi, Elisa Manzini, Pier Giuseppe Fogli, Andrea Alessandri, Lavinia Patara, Enrico Scoccimarro, Simona Masina, Antonio NavarraAbstract:Under future scenarios of business-as-usual emissions, the Ocean Storage of anthropogenic carbon is anticipated to decrease because of Ocean chemistry constraints and positive feedbacks in the carbon-climate dynamics, whereas it is still unknown how the Oceanic carbon cycle will respond to more substantial mitigation scenarios. To evaluate the natural system response to prescribed atmospheric “target” concentrations and assess the response of the Ocean carbon pool to these values, 2 centennial projection simulations have been performed with an Earth System Model that includes a fully coupled carbon cycle, forced in one case with a mitigation scenario and the other with the SRES A1B scenario. End of century Ocean uptake with the mitigation scenario is projected to return to the same magnitude of carbon fluxes as simulated in 1960 in the Pacific Ocean and to lower values in the Atlantic. With A1B, the major Ocean basins are instead projected to decrease the capacity for carbon uptake globally as found with simpler carbon cycle models, while at the regional level the response is contrasting. The model indicates that the equatorial Pacific may increase the carbon uptake rates in both scenarios, owing to enhancement of the biological carbon pump evidenced by an increase in Net Community Production (NCP) following changes in the subsurface equatorial circulation and enhanced iron availability from extratropical regions. NCP is a proxy of the bulk organic carbon made available to the higher trophic levels and potentially exportable from the surface layers. The model results indicate that, besides the localized increase in the equatorial Pacific, the NCP of lower trophic levels in the northern Pacific and Atlantic Oceans is projected to be halved with respect to the current climate under a substantial mitigation scenario at the end of the twenty-first century. It is thus suggested that changes due to cumulative carbon emissions up to present and the projected concentration pathways of aerosol in the next decades control the evolution of surface Ocean biogeochemistry in the second half of this century more than the specific pathways of atmospheric CO2 concentrations.
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Global and regional Ocean carbon uptake and climate change: sensitivity to a substantial mitigation scenario
Climate Dynamics, 2011Co-Authors: Marcello Vichi, Elisa Manzini, Pier Giuseppe Fogli, Andrea Alessandri, Lavinia Patara, Enrico Scoccimarro, Simona Masina, Antonio NavarraAbstract:Under future scenarios of business-as-usual emissions, the Ocean Storage of anthropogenic carbon is anticipated to decrease because of Ocean chemistry constraints and positive feedbacks in the carbon-climate dynamics, whereas it is still unknown how the Oceanic carbon cycle will respond to more substantial mitigation scenarios. To evaluate the natural system response to prescribed atmospheric "target" concentrations and assess the response of the Ocean carbon pool to these values, 2 centennial projection simulations have been performed with an Earth System Model that includes a fully coupled carbon cycle, forced in one case with a mitigation scenario and the other with the SRES A1B scenario. End of century Ocean uptake with the mitigation scenario is projected to return to the same magnitude of carbon fluxes as simulated in 1960 in the Pacific Ocean and to lower values in the Atlantic. With A1B, the major Ocean basins are instead projected to decrease the capacity for carbon uptake globally as found with simpler carbon cycle models, while at the regional level the response is contrasting. The model indicates that the equatorial Pacific may increase the carbon uptake rates in both scenarios, owing to enhancement of the biological carbon pump evidenced by an increase in Net Community Production (NCP) following changes in the subsurface equatorial circulation and enhanced iron availability from extratropical regions. NCP is a proxy of the bulk organic carbon made available to the higher trophic levels and potentially exportable from the surface layers. The model results indicate that, besides the localized increase in the equatorial Pacific, the NCP of lower trophic levels in the northern Pacific and Atlantic Oceans is projected to be halved with respect to the current climate under a substantial mitigation scenario at the end of the twenty-first century. It is thus suggested that changes due to cumulative carbon emissions up to present and the projected concentration pathways of aerosol in the next decades control the evolution of surface Ocean biogeochemistry in the second half of this century more than the specific pathways of atmospheric CO2 concentrations. © 2011 Springer-Verlag
Lavinia Patara - One of the best experts on this subject based on the ideXlab platform.
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global and regional Ocean carbon uptake and climate change sensitivity to a substantial mitigation scenario
Climate Dynamics, 2011Co-Authors: Marcello Vichi, Elisa Manzini, Pier Giuseppe Fogli, Andrea Alessandri, Lavinia Patara, Enrico Scoccimarro, Simona Masina, Antonio NavarraAbstract:Under future scenarios of business-as-usual emissions, the Ocean Storage of anthropogenic carbon is anticipated to decrease because of Ocean chemistry constraints and positive feedbacks in the carbon-climate dynamics, whereas it is still unknown how the Oceanic carbon cycle will respond to more substantial mitigation scenarios. To evaluate the natural system response to prescribed atmospheric “target” concentrations and assess the response of the Ocean carbon pool to these values, 2 centennial projection simulations have been performed with an Earth System Model that includes a fully coupled carbon cycle, forced in one case with a mitigation scenario and the other with the SRES A1B scenario. End of century Ocean uptake with the mitigation scenario is projected to return to the same magnitude of carbon fluxes as simulated in 1960 in the Pacific Ocean and to lower values in the Atlantic. With A1B, the major Ocean basins are instead projected to decrease the capacity for carbon uptake globally as found with simpler carbon cycle models, while at the regional level the response is contrasting. The model indicates that the equatorial Pacific may increase the carbon uptake rates in both scenarios, owing to enhancement of the biological carbon pump evidenced by an increase in Net Community Production (NCP) following changes in the subsurface equatorial circulation and enhanced iron availability from extratropical regions. NCP is a proxy of the bulk organic carbon made available to the higher trophic levels and potentially exportable from the surface layers. The model results indicate that, besides the localized increase in the equatorial Pacific, the NCP of lower trophic levels in the northern Pacific and Atlantic Oceans is projected to be halved with respect to the current climate under a substantial mitigation scenario at the end of the twenty-first century. It is thus suggested that changes due to cumulative carbon emissions up to present and the projected concentration pathways of aerosol in the next decades control the evolution of surface Ocean biogeochemistry in the second half of this century more than the specific pathways of atmospheric CO2 concentrations.
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Global and regional Ocean carbon uptake and climate change: sensitivity to a substantial mitigation scenario
Climate Dynamics, 2011Co-Authors: Marcello Vichi, Elisa Manzini, Pier Giuseppe Fogli, Andrea Alessandri, Lavinia Patara, Enrico Scoccimarro, Simona Masina, Antonio NavarraAbstract:Under future scenarios of business-as-usual emissions, the Ocean Storage of anthropogenic carbon is anticipated to decrease because of Ocean chemistry constraints and positive feedbacks in the carbon-climate dynamics, whereas it is still unknown how the Oceanic carbon cycle will respond to more substantial mitigation scenarios. To evaluate the natural system response to prescribed atmospheric "target" concentrations and assess the response of the Ocean carbon pool to these values, 2 centennial projection simulations have been performed with an Earth System Model that includes a fully coupled carbon cycle, forced in one case with a mitigation scenario and the other with the SRES A1B scenario. End of century Ocean uptake with the mitigation scenario is projected to return to the same magnitude of carbon fluxes as simulated in 1960 in the Pacific Ocean and to lower values in the Atlantic. With A1B, the major Ocean basins are instead projected to decrease the capacity for carbon uptake globally as found with simpler carbon cycle models, while at the regional level the response is contrasting. The model indicates that the equatorial Pacific may increase the carbon uptake rates in both scenarios, owing to enhancement of the biological carbon pump evidenced by an increase in Net Community Production (NCP) following changes in the subsurface equatorial circulation and enhanced iron availability from extratropical regions. NCP is a proxy of the bulk organic carbon made available to the higher trophic levels and potentially exportable from the surface layers. The model results indicate that, besides the localized increase in the equatorial Pacific, the NCP of lower trophic levels in the northern Pacific and Atlantic Oceans is projected to be halved with respect to the current climate under a substantial mitigation scenario at the end of the twenty-first century. It is thus suggested that changes due to cumulative carbon emissions up to present and the projected concentration pathways of aerosol in the next decades control the evolution of surface Ocean biogeochemistry in the second half of this century more than the specific pathways of atmospheric CO2 concentrations. © 2011 Springer-Verlag
Andrea Alessandri - One of the best experts on this subject based on the ideXlab platform.
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global and regional Ocean carbon uptake and climate change sensitivity to a substantial mitigation scenario
Climate Dynamics, 2011Co-Authors: Marcello Vichi, Elisa Manzini, Pier Giuseppe Fogli, Andrea Alessandri, Lavinia Patara, Enrico Scoccimarro, Simona Masina, Antonio NavarraAbstract:Under future scenarios of business-as-usual emissions, the Ocean Storage of anthropogenic carbon is anticipated to decrease because of Ocean chemistry constraints and positive feedbacks in the carbon-climate dynamics, whereas it is still unknown how the Oceanic carbon cycle will respond to more substantial mitigation scenarios. To evaluate the natural system response to prescribed atmospheric “target” concentrations and assess the response of the Ocean carbon pool to these values, 2 centennial projection simulations have been performed with an Earth System Model that includes a fully coupled carbon cycle, forced in one case with a mitigation scenario and the other with the SRES A1B scenario. End of century Ocean uptake with the mitigation scenario is projected to return to the same magnitude of carbon fluxes as simulated in 1960 in the Pacific Ocean and to lower values in the Atlantic. With A1B, the major Ocean basins are instead projected to decrease the capacity for carbon uptake globally as found with simpler carbon cycle models, while at the regional level the response is contrasting. The model indicates that the equatorial Pacific may increase the carbon uptake rates in both scenarios, owing to enhancement of the biological carbon pump evidenced by an increase in Net Community Production (NCP) following changes in the subsurface equatorial circulation and enhanced iron availability from extratropical regions. NCP is a proxy of the bulk organic carbon made available to the higher trophic levels and potentially exportable from the surface layers. The model results indicate that, besides the localized increase in the equatorial Pacific, the NCP of lower trophic levels in the northern Pacific and Atlantic Oceans is projected to be halved with respect to the current climate under a substantial mitigation scenario at the end of the twenty-first century. It is thus suggested that changes due to cumulative carbon emissions up to present and the projected concentration pathways of aerosol in the next decades control the evolution of surface Ocean biogeochemistry in the second half of this century more than the specific pathways of atmospheric CO2 concentrations.
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Global and regional Ocean carbon uptake and climate change: sensitivity to a substantial mitigation scenario
Climate Dynamics, 2011Co-Authors: Marcello Vichi, Elisa Manzini, Pier Giuseppe Fogli, Andrea Alessandri, Lavinia Patara, Enrico Scoccimarro, Simona Masina, Antonio NavarraAbstract:Under future scenarios of business-as-usual emissions, the Ocean Storage of anthropogenic carbon is anticipated to decrease because of Ocean chemistry constraints and positive feedbacks in the carbon-climate dynamics, whereas it is still unknown how the Oceanic carbon cycle will respond to more substantial mitigation scenarios. To evaluate the natural system response to prescribed atmospheric "target" concentrations and assess the response of the Ocean carbon pool to these values, 2 centennial projection simulations have been performed with an Earth System Model that includes a fully coupled carbon cycle, forced in one case with a mitigation scenario and the other with the SRES A1B scenario. End of century Ocean uptake with the mitigation scenario is projected to return to the same magnitude of carbon fluxes as simulated in 1960 in the Pacific Ocean and to lower values in the Atlantic. With A1B, the major Ocean basins are instead projected to decrease the capacity for carbon uptake globally as found with simpler carbon cycle models, while at the regional level the response is contrasting. The model indicates that the equatorial Pacific may increase the carbon uptake rates in both scenarios, owing to enhancement of the biological carbon pump evidenced by an increase in Net Community Production (NCP) following changes in the subsurface equatorial circulation and enhanced iron availability from extratropical regions. NCP is a proxy of the bulk organic carbon made available to the higher trophic levels and potentially exportable from the surface layers. The model results indicate that, besides the localized increase in the equatorial Pacific, the NCP of lower trophic levels in the northern Pacific and Atlantic Oceans is projected to be halved with respect to the current climate under a substantial mitigation scenario at the end of the twenty-first century. It is thus suggested that changes due to cumulative carbon emissions up to present and the projected concentration pathways of aerosol in the next decades control the evolution of surface Ocean biogeochemistry in the second half of this century more than the specific pathways of atmospheric CO2 concentrations. © 2011 Springer-Verlag
Ken Caldeira - One of the best experts on this subject based on the ideXlab platform.
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Ocean Storage of CO2
Elements, 2008Co-Authors: E. Eric Adams, Ken CaldeiraAbstract:One method for minimizing climate change is to capture CO2 from power plants and inject it into the deep Ocean, thus reducing the magnitude and rate of change of CO2 concentration in the atmosphere and the surface Ocean. Many discharge options are possible, with varied mixing and retention characteristics. The Ocean's capacity is vast, and mathematical models suggest that injected CO2 could remain sequestered for several hundred years. While theoretical and laboratory studies support the viability of Ocean Storage, field experiments are necessary to realistically evaluate the environmental impact.
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Differing methods of accounting Ocean carbon sequestration efficiency
Journal of Geophysical Research, 2004Co-Authors: Kevin J. Mueller, Ken Caldeira, Long Cao, Atul K. JainAbstract:[1] Presently, much of CO2 fossil-fuel emissions are removed from the atmosphere through natural Ocean uptake of CO2. Many schemes have now been proposed by which the accumulation of anthropogenic CO2 in the atmosphere could be slowed with intentional further Storage of CO2 in the Ocean. Our review of the literature indicates inconsistency in whether ambient Ocean carbon uptake is included when accounting for the effectiveness of such schemes. This inconsistency is a consequence of differing choices of atmospheric boundary condition. In the case of one particular form of Ocean sequestration, namely direct injection of liquefied CO2 emissions into the Ocean interior, this choice is the determination of whether the atmospheric CO2 concentration responsively increases due to leakage of injected carbon from the Ocean or retains a specified value. We first show how results of simulations using these two different boundary conditions can be related with the convolution of an atmosphere pulse release. We then use a numerical model to present a more complete analysis of the role of these boundary conditions. Finally, we suggest that a responsive atmospheric CO2 boundary condition is appropriate for predicting future carbon concentrations, but a specified atmospheric CO2 boundary condition is appropriate for evaluating how much CO2 Storage should be attributed to an Ocean Storage project.
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The role of the southern Ocean in uptake and Storage of anthropogenic carbon dioxide
Science, 2000Co-Authors: Ken Caldeira, Philip B. DuffyAbstract:An Ocean-climate model that shows high fluxes of anthropogenic carbon dioxide into the Southern Ocean, but very low Storage of anthropogenic carbon there, agrees with observation-based estimates of Ocean Storage of anthropogenic carbon dioxide. This low simulated Storage indicates a subordinate role for deep convection in the present-day Southern Ocean. The primary mechanism transporting anthropogenic carbon out of the Southern Ocean is isopycnal transport. These results imply that if global climate change reduces the density of surface waters in the Southern Ocean, isopycnal surfaces that now outcrop may become isolated from the atmosphere, tending to diminish Southern Ocean carbon uptake.
Peter M. Haugan - One of the best experts on this subject based on the ideXlab platform.
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Ocean abyssal carbon experiments at 0.7 and 4 KM depth
Greenhouse Gas Control Technologies 7, 2005Co-Authors: Peter M. Haugan, Yasuharu Nakajima, Ryuji Kojima, Kenji Yamane, Izuo Aya, Peter G. Brewer, Edward T. Peltzer, Peter Walz, Noriko Nakayama, Joakim HoveAbstract:Publisher Summary The chapter reviews and compares observations from the two experiments performed in 2003. The main focus is on the way in which CO 2 behaves and is transported away from the site in realistic deep-sea conditions where hydrates form and where CO 2 is exposed to sediments. The synthesis of observations is then used as a basis for discussing and presenting best estimates of the fate of larger quantities of CO 2 placed on the seafloor. The chapter also discusses observations from small-scale CO 2 experiments conducted off the coast of California at 684 m depth and at 3942 m depth. In both experiments, when the seawater velocity was sufficiently strong, parcels of liquid CO 2 were torn off and transported away as discrete units by the turbulent water current. In the deep experiment, newly formed frazil hydrate was observed at the interface, occasionally including sediment particles. Hydrate furthermore collected and created a floating consolidated solid in the downstream end of the trough, dissolving slowly from one day to the next. These observations have important implications for understanding and modeling of larger scale disposal at the seafloor. When CO 2 is released by the interfacial instability mechanism driven by strong currents, the seawater density increase due to dissolution of CO 2 may not have time to act and stabilize the water column before the discrete parcels of liquid phase CO 2 are advected away from the disposal site. The floating solid that formed at the interface is hypothesized to consist of hydrate and additional trapped seawater. Its appearance was not expected in advance and its role in delaying dissolution cannot be determined from the present experimental set-up. A capability for long-term seafloor perturbation experiments is deemed to be crucial both for direct Ocean-Storage research and for studying effects of invasion of anthropogenic CO 2 from the atmosphere.
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Progress of COSMOS (CO2 Sending Method for Ocean Storage) and OACE (Ocean Abyssal Carbon Experiment)
Volume 1: Offshore Technology; Ocean Space Utilization, 2003Co-Authors: Izuo Aya, Yasuharu Nakajima, Hideyuki Shirota, Ryuji Kojima, Kenji Yamane, Sadahiro Namie, Peter G. Brewer, Edward T. Peltzer, Peter M. Haugan, Truls JohannessenAbstract:The Storage of liquid CO2 at an Ocean floor, one of promising measures to mitigate the global warming, requires 3500 m depth for the gravitationally stable Storage, a breakthrough technology and a reasonable cost to realize, although it has large advantages such as the sequestration term longer than 2000 years. However CO2 can be sent to the Ocean floor by shallow release, if we can use the nature that the cold CO2 to be shipped by a CO2 carrier is much denser than the ambient seawater even at shallow depths. The National Maritime Research Institute (NMRI) conducted several joint field CO2 release experiments with the Monterey Bay Aquarium Research Institute (MBARI, USA) since 1999 under the auspices of the NEDO, and proposed the improved COSMOS, CO2 Sending Method for Ocean Storage, in which CO2 is released into 200 m depth as slurry masses (mixture of dry ice and cold liquid CO2 ). Since 2002, under the NEDO Grant, the NMRI started a new international joint research, OACE, Ocean Abyssal Carbon Experiment with the MBARI and the University of Bergen (UoB, Norway), in order to accumulate the basic data on the long-term stability of stored CO2 and its environmental effects around Storage site.Copyright © 2003 by ASME
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On the Production and Use of Scientific Knowledge About Ocean Sequestration
Greenhouse Gas Control Technologies - 6th International Conference, 2003Co-Authors: Peter M. HauganAbstract:Publisher Summary Planned small scale Ocean experiments designed to learn the possibilities and limitations of direct Ocean Storage of CO2 have recently met with sufficient opposition to be stopped at the highest political level in Norway. In this case, sentiments and appeals to irrational feelings were decisive. Obligations through previous permits and commitments, freedom of research, and hard scientific facts were less important. The production of scientific knowledge was interrupted and may be set back for a long time because scientists and their institutions will prefer to work on other problems with less interference and disturbances. Some environmental organizations see the value and importance of science as a basis for decision-making. Global environmental problems facing mankind are complicated and interconnected. It is suggested that there is a need for a clean separation between the production of knowledge by scientists and the use of the knowledge in informed decisions by the public through democratically elected politicians and intergovernmental mechanisms. A higher public respect for unbiased and “value-free” natural science and improved communication between scientists and stakeholders is required. It is proposed that existing mechanisms and organizations may be used to promote consensus building and guide environmental impact assessments in the case of Ocean sequestration.
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Impacts on the marine environment from direct and indirect Ocean Storage of CO2
Waste Management, 1998Co-Authors: Peter M. HauganAbstract:Abstract The potential effects of CO 2 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 CO 2 emissions to the atmosphere penetrating into the Oceans. The perturbation of the marine environment through such indirect, i.e. via the atmosphere, Storage of CO 2 in the Oceans may be estimated based on known and predicted atmospheric CO 2 levels. Capture of CO 2 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 CO 2 levels. Direct Storage of CO 2 in the Oceans may impose, at least locally, a stronger perturbation of the marine environment than indirect Storage via the atmosphere. Storage of waste CO 2 in aquifers below the seabed may also affect the marine environment if CO 2 leaks out in the water column above. In view of the perturbations of the marine environment that are already ongoing as a consequence of CO 2 emissions to the atmosphere and which will accelerate in the business-as-usual scenario as well as in scenarios including realistic CO 2 removal options, there is a need to clarify the resilience of marine ecosystems to increased CO 2 . 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 CO 2 policies are briefly described.