Today I want to briefly amend another aspect to the method introduced in my last post. The study by Bala et al. (2010) deals with impacts of cloud-seeding on the hydrological cycle. The method of cloud-seeding produces low-level clouds only above the ocean while the cloud layer above land remains unmodified. That means solar radiation is only reduced over the oceans. Nevertheless this geo-engineering method has an impact in the whole hydrological system. The article further describes that reflecting radiation via maritime clouds leads to a decrease in global mean precipitation and evaporation (1.3%) but an increase in runoff over land (7.5%) and land-mean precipitation. According to the study this is a result of the cooling of the atmosphere over the oceans which leads to a ‘monsoonal circulation with rising motion over land (...), and sinking motion over ocean with associated statistically significant increases in precipitation over land.’ (Bala et al. (2010): 927)
The study emphasises that an enhancement of albedo does not only have a cooling effect for our climate, but that that there are other side effects that have to be kept in mind. It is mentioned that those results contrast with previous studies, which is why further research is necessary before a decision on the implementation of cloud-seeding on a global scale is made.
Literature:
Bala, G., Caldreia, K., Nemani, R., Cao, L., Ban-Weiss, G., and Shin, H.-J.: Albedo enhancement of marine cloud to counteract global warming: impacts on the hydrological cycle, Clim. Dy- nam., doi:10.1007/s00382-010-0868-1, 2010.
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