21-08-2011, 04:48 AM
GREG SAYS, The "transparency" of C02 has nothing at all to do with this, Gary. There is a gas called, Dimethylsulfide (or DMS for short). This gas is responsible for well over 90% of the release of oceanic sulphuric gas, and accounts for a significant amount of cloud formation because it oxidizes (in the atmosphere) resulting in sulfate aerosols, which in turn seed cloud condensation. Its relationship to increased C02 is a subject you would perhaps do well to study.
Gary says,
Is the CLAW hypothesis dead?
The CLAW hypothesis takes its name from Charlson, Lovelock, Andreae and Warren, whose 1987 paper suggested that phytoplankton could help regulate Earth's climate. Phytoplankton single-celled algae emit a gas called dimethylsulphide (DMS) and the authors suggested that DMS forms tiny new particles (or aerosol) in the atmosphere which controls climate by affecting the amount of sunlight reflected by clouds. New aerosol particles from DMS have the potential to increase cloud reflectivity because they are effective cloud condensation nuclei and can increase the number of cloud drops.
However, new results from GLOMAP suggest that CLAW may be very weak.
The key aerosol quantity is the number concentration of cloud condensation nuclei (CCN), but until recently global models did not include the necessary aerosol physics to quantify CCN. We used GLOMAP to calculate the sensitivity of CCN to changes in DMS emission using multiple present-day and future sea-surface DMS climatologies.
The DMS flux from a future globally warmed climatology was 0.2 Tg (sulphur) per year higher than present day. The largest CCN response to this extra DMS was seen in the Southern Ocean, contributing to a Southern Hemisphere mean annual increase of less than 0.2%.
We show that the changes in DMS flux and CCN concentration between the present day and global warming scenario are similar to interannual differences due to variability in windspeed. So although DMS makes a significant contribution to global marine CCN concentrations, the sensitivity of CCN to potential future changes in DMS flux is very low. This finding, together with the predicted small changes in future seawater DMS concentrations, suggests that the role of DMS in climate regulation is very weak.
Gary says,
Is the CLAW hypothesis dead?
The CLAW hypothesis takes its name from Charlson, Lovelock, Andreae and Warren, whose 1987 paper suggested that phytoplankton could help regulate Earth's climate. Phytoplankton single-celled algae emit a gas called dimethylsulphide (DMS) and the authors suggested that DMS forms tiny new particles (or aerosol) in the atmosphere which controls climate by affecting the amount of sunlight reflected by clouds. New aerosol particles from DMS have the potential to increase cloud reflectivity because they are effective cloud condensation nuclei and can increase the number of cloud drops.
However, new results from GLOMAP suggest that CLAW may be very weak.
The key aerosol quantity is the number concentration of cloud condensation nuclei (CCN), but until recently global models did not include the necessary aerosol physics to quantify CCN. We used GLOMAP to calculate the sensitivity of CCN to changes in DMS emission using multiple present-day and future sea-surface DMS climatologies.
The DMS flux from a future globally warmed climatology was 0.2 Tg (sulphur) per year higher than present day. The largest CCN response to this extra DMS was seen in the Southern Ocean, contributing to a Southern Hemisphere mean annual increase of less than 0.2%.
We show that the changes in DMS flux and CCN concentration between the present day and global warming scenario are similar to interannual differences due to variability in windspeed. So although DMS makes a significant contribution to global marine CCN concentrations, the sensitivity of CCN to potential future changes in DMS flux is very low. This finding, together with the predicted small changes in future seawater DMS concentrations, suggests that the role of DMS in climate regulation is very weak.