Title:- Effects of Marine Cloud Brightening on Polar Regions and Meridional Heat Flux

Marine cloud brightening (MCB) is one of several proposed solar radiation management geoengineering schemes designed to enhance the albedo of marine stratocumulus clouds, with concomitant overall cooling, and the intention of averting some of the undesirable effects of climate change (Latham et al. 2008, 2012). Such changes include ice loss, desertification and increased sea levels. Polar sea ice fraction has been recorded by satellite data for the last 40 years. This data shows a general long term reduction in sea ice thickness and area and this reduction has been attributed to climate change. Changes in climate have been reported to be disproportionately larger in polar regions. The HadGEM1 (UK Met Office Climate Model, V6.1) is a fully coupled climate model. It is used to project changes in polar ice cover and temperatures as a result of increasing carbon dioxide and the deployment of MCB geoengineering. The meridional heat flux is the mechanism for moving energy from the tropics to the polar regions. The results show that for a comparison between a control (~ 2020 carbon dioxide concentrations) and a double pre-industrial carbon dioxide simulation, the maximum meridional heat flux is found to change from 5.8 PW to 6.1 PW. With three-region MCB seeding of marine stratocumulus, this is reduced to 5.7 PW. Application of a three region seeding scenario, results an increase insea ice cover to 0.20 million sq km above the initial values. ( Parkes et al. 2012 ) Latham J. et al (2008) Global temperature stabilization. Phil Trans Roy Soc A. doi 10.1098/rsta.2008.0137 Latham J et al (2012) Marine Cloud Brighetening. Phil Trans Ro Soc A. In press rsta 1012.0086