A plan to produce more natural dimethyl sulfide (DMS) has been proposed. DMS is a major source of nuclei that make clouds and would lead to more sunlight reflected to space and cooler temperatures.
July 25, 2007 (Press Release) --
SOCORRO, NM July 26, 2007: Prof. Oliver Wingenter of New Mexico Tech and his colleagues propose a limited iron fertilization of the Southern Ocean as a means to stimulate the natural sulfur cycle associated with marine phytoplankton which could result in increased cloud reflectivity that would cool the Earth and possibly slow sea level rise.
Wingenter and his research colleagues Dr. Scott M. Elliot at Los Alamos National Laboratory and Prof. Donald R. Blake at University of California, Irvine report their findings in the article "New Directions: Enhancing the natural sulfur cycle to slow global warming" published July 18 in the journal Atmospheric Environment.
The scientists base their plan on their observations made during the 2002 Southern Ocean Iron Experiments (SOFeX) research expedition. During the SOFeX, two patches of the Southern Ocean approximately 100 square miles in area each were fertilized with trace amounts of iron in order to see if an increase in populations of marine, single-cell algae known as phytoplankton could be used to remove, or "sink," carbon dioxide---from the atmosphere into the deep ocean. However, the effectiveness of iron fertilization for sequestering significant amounts of carbon dioxide is still in question. "However, phytoplankton not only consume inorganic carbon, but also produce and consume many climate-relevant organic gases." Wingenter continues. "The greatest climate effect of iron fertilization may be in enhancing dimethyl sulfide (DMS) production, leading to changes in the optical properties of the atmosphere and cooling of the region." Samples taken by Wingenter during SOFeX showed that the concentration of DMS increased about five times in the iron fertilized area. Emissions of DMS are the main source of sulfate particle formation to the region and "seed" much of the cloud formation.
Wingenter and his research colleagues propose a limited fertilization of only about 2 percent of Southern Ocean---which would result in an estimated two degrees (Celsius) cooling of the region. A program of limited-scale iron fertilization in the Southern Ocean and perhaps a portion of the equatorial Pacific may have the potential to set back the tipping point of global warming from about 10 years to about 20 or more years." Wingenter estimates.
The program envisioned by Wingenter would require about 30 ships at an annual cost of about $50 million. Results could be verified by satellites and any unforeseen consequences would need to be monitored. A danger is that policy makers might view proposed geoengineering solutions an excuse not to deal with cutting back CO2 emissions.
"Our plan to enhance the sulfur cycle must be differentiated from previous plans of massive iron enhancements to sequester CO2. Full-scale iron fertilization of the Southern Ocean must be ruled out simply because major cooling of the region by increased DMS would result in a temperature drop of perhaps 10 degrees Celsius or more."
Wingenter and his research colleagues Dr. Scott M. Elliot at Los Alamos National Laboratory and Prof. Donald R. Blake at University of California, Irvine report their findings in the article "New Directions: Enhancing the natural sulfur cycle to slow global warming" published July 18 in the journal Atmospheric Environment.
The scientists base their plan on their observations made during the 2002 Southern Ocean Iron Experiments (SOFeX) research expedition. During the SOFeX, two patches of the Southern Ocean approximately 100 square miles in area each were fertilized with trace amounts of iron in order to see if an increase in populations of marine, single-cell algae known as phytoplankton could be used to remove, or "sink," carbon dioxide---from the atmosphere into the deep ocean. However, the effectiveness of iron fertilization for sequestering significant amounts of carbon dioxide is still in question. "However, phytoplankton not only consume inorganic carbon, but also produce and consume many climate-relevant organic gases." Wingenter continues. "The greatest climate effect of iron fertilization may be in enhancing dimethyl sulfide (DMS) production, leading to changes in the optical properties of the atmosphere and cooling of the region." Samples taken by Wingenter during SOFeX showed that the concentration of DMS increased about five times in the iron fertilized area. Emissions of DMS are the main source of sulfate particle formation to the region and "seed" much of the cloud formation.
Wingenter and his research colleagues propose a limited fertilization of only about 2 percent of Southern Ocean---which would result in an estimated two degrees (Celsius) cooling of the region. A program of limited-scale iron fertilization in the Southern Ocean and perhaps a portion of the equatorial Pacific may have the potential to set back the tipping point of global warming from about 10 years to about 20 or more years." Wingenter estimates.
The program envisioned by Wingenter would require about 30 ships at an annual cost of about $50 million. Results could be verified by satellites and any unforeseen consequences would need to be monitored. A danger is that policy makers might view proposed geoengineering solutions an excuse not to deal with cutting back CO2 emissions.
"Our plan to enhance the sulfur cycle must be differentiated from previous plans of massive iron enhancements to sequester CO2. Full-scale iron fertilization of the Southern Ocean must be ruled out simply because major cooling of the region by increased DMS would result in a temperature drop of perhaps 10 degrees Celsius or more."
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