Daily Archives: August 3, 2011

Two Recent Dust and Climate Papers

G. S. Okin et al., 2011. Dust: Small-Scale Processes With Global Consequences. EOS. volume 92 number 29 19 July 2011. pages 241-241.

This paper discusses the importance of atmospheric dust on climate.  Click here for a further discussion of the significance of this article. 


Solomon, S., J.S. Daniel, R.R. Neely III, J.P. Vernier, E.G. Dutton, and L.W. Thomason 2011. The Persistently Variable “Background” Stratospheric Aerosol Layer and Global Climate Change, Science DOI:10.1126/science.1206027


Click here for the abstract (also below) and to obtain the paper.

Recent measurements demonstrate that the “background” stratospheric aerosol layer is persistently variable rather than constant, even in the absence of major volcanic eruptions. Several independent data sets show that stratospheric aerosols increased in abundance since 2000. Near-global satellite aerosol data imply a negative radiative forcing due to stratospheric aerosol changes over this period of about –0.1 W/m2, reducing the recent global warming that would otherwise have occurred. Observations from earlier periods are limited but suggest an additional negative radiative forcing of about –0.1 W/m2 from 1960 to 1990. Climate model projections neglecting these changes would continue to overestimate the radiative forcing and global warming in coming decades if these aerosols remain present at current values or increase.


Press Misinformation: San Francisco Water

Several news articles have appeared such as this one (click here) saying that San Franciso drinking water may be  unsafe for people with HIV/AIDS. The San Francisco Public Utilities Commission has installed UV disinfection. The following statement in this article is simply misleading:

“Spreck Rosekrans, a water expert, says the process San Francisco uses is one where the water is chemically treated with chloramine and radiated with ultraviolet light, but unlike other areas, it is not filtered to kill certain microorganisms such as the protozoans that cause giardia and cryptosporidiosis. These microorganisms can be potentially unsafe for people with weakened immune systems, like those with HIV or AIDs.”

The UV disinfection process is intended to kill cryptosporidium and is also effective against giardia and bacteria. Filtration can physically remove these organisms, but is not necessarily needed here. This article is unnecessarily alarmist.