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Enhanced marine sulphur emissions offset global warming and impact rainfall.

Grandey BS, Wang C - Sci Rep (2015)

Bottom Line: The associated increase in marine primary productivity may lead to an increase in emissions of dimethyl sulphide (DMS), the primary source of sulphate aerosol over remote ocean regions, potentially causing direct and cloud-related indirect aerosol effects on climate.We find that the cooling effect associated with enhanced DMS emissions beneficially offsets greenhouse gas induced warming across most of the world.These results demonstrate that changes in marine phytoplankton activity may lead to a mixture of positive and negative impacts on the climate.

View Article: PubMed Central - PubMed

Affiliation: Center for Environmental Sensing and Modeling, Singapore-MIT Alliance for Research and Technology, Singapore.

ABSTRACT
Artificial fertilisation of the ocean has been proposed as a possible geoengineering method for removing carbon dioxide from the atmosphere. The associated increase in marine primary productivity may lead to an increase in emissions of dimethyl sulphide (DMS), the primary source of sulphate aerosol over remote ocean regions, potentially causing direct and cloud-related indirect aerosol effects on climate. This pathway from ocean fertilisation to aerosol induced cooling of the climate may provide a basis for solar radiation management (SRM) geoengineering. In this study, we investigate the transient climate impacts of two emissions scenarios: an RCP4.5 (Representative Concentration Pathway 4.5) control; and an idealised scenario, based on RCP4.5, in which DMS emissions are substantially enhanced over ocean areas. We use mini-ensembles of a coupled atmosphere-ocean configuration of CESM1(CAM5) (Community Earth System Model version 1, with the Community Atmosphere Model version 5). We find that the cooling effect associated with enhanced DMS emissions beneficially offsets greenhouse gas induced warming across most of the world. However, the rainfall response may adversely affect water resources, potentially impacting human livelihoods. These results demonstrate that changes in marine phytoplankton activity may lead to a mixture of positive and negative impacts on the climate.

No MeSH data available.


Annual DMS emissions for the (a) RCP4.5 and (b) EnDMS scenarios. Global totals are provided at the side of each map. The mass unit “g(S)” refers to grams of sulphur. For each latitude band and month, the oceanic DMS emissions in EnDMS are equal to the maximum found in RCP4.5. Since the EnDMS emissions are constructed for each month separately, the annual DMS emissions in EnDMS can be greater than the annual RCP4.5 maximum for any given latitude. The figure was created using Python.
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f1: Annual DMS emissions for the (a) RCP4.5 and (b) EnDMS scenarios. Global totals are provided at the side of each map. The mass unit “g(S)” refers to grams of sulphur. For each latitude band and month, the oceanic DMS emissions in EnDMS are equal to the maximum found in RCP4.5. Since the EnDMS emissions are constructed for each month separately, the annual DMS emissions in EnDMS can be greater than the annual RCP4.5 maximum for any given latitude. The figure was created using Python.

Mentions: “EnDMS”, an experimental scenario with enhanced DMS emissions (Fig. 1). Following idealised assumptions about nutrient limitation and the other factors affecting DMS emissions (see Methods), EnDMS can be interpreted as an idealised upper-bound scenario in which ocean fertilisation prevents nutrient limitation of DMS emissions.


Enhanced marine sulphur emissions offset global warming and impact rainfall.

Grandey BS, Wang C - Sci Rep (2015)

Annual DMS emissions for the (a) RCP4.5 and (b) EnDMS scenarios. Global totals are provided at the side of each map. The mass unit “g(S)” refers to grams of sulphur. For each latitude band and month, the oceanic DMS emissions in EnDMS are equal to the maximum found in RCP4.5. Since the EnDMS emissions are constructed for each month separately, the annual DMS emissions in EnDMS can be greater than the annual RCP4.5 maximum for any given latitude. The figure was created using Python.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4543957&req=5

f1: Annual DMS emissions for the (a) RCP4.5 and (b) EnDMS scenarios. Global totals are provided at the side of each map. The mass unit “g(S)” refers to grams of sulphur. For each latitude band and month, the oceanic DMS emissions in EnDMS are equal to the maximum found in RCP4.5. Since the EnDMS emissions are constructed for each month separately, the annual DMS emissions in EnDMS can be greater than the annual RCP4.5 maximum for any given latitude. The figure was created using Python.
Mentions: “EnDMS”, an experimental scenario with enhanced DMS emissions (Fig. 1). Following idealised assumptions about nutrient limitation and the other factors affecting DMS emissions (see Methods), EnDMS can be interpreted as an idealised upper-bound scenario in which ocean fertilisation prevents nutrient limitation of DMS emissions.

Bottom Line: The associated increase in marine primary productivity may lead to an increase in emissions of dimethyl sulphide (DMS), the primary source of sulphate aerosol over remote ocean regions, potentially causing direct and cloud-related indirect aerosol effects on climate.We find that the cooling effect associated with enhanced DMS emissions beneficially offsets greenhouse gas induced warming across most of the world.These results demonstrate that changes in marine phytoplankton activity may lead to a mixture of positive and negative impacts on the climate.

View Article: PubMed Central - PubMed

Affiliation: Center for Environmental Sensing and Modeling, Singapore-MIT Alliance for Research and Technology, Singapore.

ABSTRACT
Artificial fertilisation of the ocean has been proposed as a possible geoengineering method for removing carbon dioxide from the atmosphere. The associated increase in marine primary productivity may lead to an increase in emissions of dimethyl sulphide (DMS), the primary source of sulphate aerosol over remote ocean regions, potentially causing direct and cloud-related indirect aerosol effects on climate. This pathway from ocean fertilisation to aerosol induced cooling of the climate may provide a basis for solar radiation management (SRM) geoengineering. In this study, we investigate the transient climate impacts of two emissions scenarios: an RCP4.5 (Representative Concentration Pathway 4.5) control; and an idealised scenario, based on RCP4.5, in which DMS emissions are substantially enhanced over ocean areas. We use mini-ensembles of a coupled atmosphere-ocean configuration of CESM1(CAM5) (Community Earth System Model version 1, with the Community Atmosphere Model version 5). We find that the cooling effect associated with enhanced DMS emissions beneficially offsets greenhouse gas induced warming across most of the world. However, the rainfall response may adversely affect water resources, potentially impacting human livelihoods. These results demonstrate that changes in marine phytoplankton activity may lead to a mixture of positive and negative impacts on the climate.

No MeSH data available.