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The Biological Atmosphere: Too Long Ignored by the IPCC?
Volume 10, Number 51: 19 December 2007

In a recent Research Front article in Environmental Chemistry, Jaenicke et al. (2007) review the status of research being conducted on biological materials in the atmosphere, which they denominate primary biological atmospheric particles or PBAPs. Originally, these particles were restricted to culture forming units, including pollen, bacteria, mold and viruses, but they also include fragments of living and dead organisms and plant debris, human and animal epithelial cells, broken hair filaments, parts of insects, shed feather fractions, etc., which they lump together under the category of dead biological matter.

With respect to the meteorological and climatic relevance of these particles, they note that many PBAPs, including "decaying vegetation, marine plankton and bacteria are excellent ice nuclei," and they say that "one can easily imagine the[ir] influence on cloud cover, climate forcing and feedback and global precipitation distribution."

In describing their own measurements and those of others, which they say "have now been carried out at several geographical locations covering all seasons of the year and many characteristic environments," Jaenicke et al. report that "by number and volume, the PBAP fraction is ~20% of the total aerosol, and appears rather constant during the year." In addition, they write that "the impression prevails that the biological material, whether produced directly or shed during the seasons, sits on surfaces, ready to be lifted again in resuspension."

In a brief summation of their findings, the German researchers say "the overall conclusion can only be that PBAPs are a major fraction of atmospheric aerosols, and are comparable to sea salt over the oceans and mineral particles over the continents," and, consequently, that "the biosphere must be a major source for directly injected biological particles, and those particles should be taken into account in understanding and modeling atmospheric processes." However, they note that "the IPCC-Report of 2007 does not even mention these particles [our italics and boldface]," and that "this disregard of the biological particles requires a new attitude."

We agree. And we hope that that attitude includes a willingness to acknowledge that, as comprehensive as current state-of-the-art climate models might be, there is much of significance that is not included in them, and that when that which is missing is finally factored in and properly modeled, it could well result in radically different conclusions being reached from those that are currently held by the IPCC.

Sherwood, Keith and Craig Idso

Reference
Jaenicke, R., Matthias-Maser, S. and Gruber, S. 2007. Omnipresence of biological material in the atmosphere. Environmental Chemistry 4: 217-220.