If you use GM or breeding to boost aerosol levels it might be harmful. A On 27 Feb 2014 15:29, "Simone Tilmes" <[email protected]> wrote:
> VOC's are emitted from the forest and have an impact on climate, however, > how much they really change with increasing CO2 levels is questionable and > may go in both directions. To really change the amount of aerosols that > build up over the forests, afforestation would be the way to go. That > certainly would be a good way to "manipulate climate" because more forest > increases the CO2 uptake and it maybe more important for climate than the > change in aerosols. I don't see the health effect playing a role, is it > unhealthy to walk through a forest? > > Simone > >> >> Poster's note : I've been wondering about whether this mechanism can be >> manipulated for geoengineering purposes. David Keith is concerned about >> health effects, suggesting they will outweigh relative benefits. >> >> http://www.nature.com/nature/journal/v506/n7489/full/nature13032.html >> >> A large source of low-volatility secondary organic aerosol >> >> Mikael Ehn, Joel A. Thornton, Einhard Kleist, Mikko Sipilä, Heikki >> Junninen, Iida Pullinen, Monika Springer, Florian Rubach, Ralf Tillmann, >> Ben Lee,Felipe Lopez-Hilfiker, Stefanie Andres, Ismail-Hakki Acir, Matti >> Rissanen, Tuija Jokinen, Siegfried Schobesberger, Juha Kangasluoma, Jenni >> Kontkanen,Tuomo Nieminen, Theo Kurtén, Lasse B. Nielsen,Solvejg Jørgensen, >> Henrik G. Kjaergaard, Manjula Canagaratna, Miikka Dal Maso et al. >> >> Nature 506, 476–479 (27 February 2014)doi:10.1038/nature13032 >> >> Published online 26 February 2014 >> >> Article tools >> >> Forests emit large quantities of volatile organic compounds (VOCs) to the >> atmosphere. Their condensable oxidation products can form secondary organic >> aerosol, a significant and ubiquitous component of atmospheric aerosol, >> which is known to affect the Earth’s radiation balance by scattering solar >> radiation and by acting as cloud condensation nuclei. The quantitative >> assessment of such climate effects remains hampered by a number of factors, >> including an incomplete understanding of how biogenic VOCs contribute to >> the formation of atmospheric secondary organic aerosol. The growth of newly >> formed particles from sizes of less than three nanometres up to the sizes >> of cloud condensation nuclei (about one hundred nanometres) in many >> continental ecosystems requires abundant, essentially non-volatile organic >> vapours, but the sources and compositions of such vapours remain unknown. >> Here we investigate the oxidation of VOCs, in particular the terpene >> α-pinene, under atmospherically relevant conditions in chamber experiments. >> We find that a direct pathway leads from several biogenic VOCs, such as >> monoterpenes, to the formation of large amounts of extremely low-volatility >> vapours. These vapours form at significant mass yield in the gas phase and >> condense irreversibly onto aerosol surfaces to produce secondary organic >> aerosol, helping to explain the discrepancy between the observed >> atmospheric burden of secondary organic aerosol and that reported by many >> model studies. We further demonstrate how these low-volatility vapours can >> enhance, or even dominate, the formation and growth of aerosol particles >> over forested regions, providing a missing link between biogenic VOCs and >> their conversion to aerosol particles. Our findings could help to improve >> assessments of biosphere–aerosol–climate feedback mechanisms, and the air >> quality and climate effects of biogenic emissions generally. >> >> -- >> You received this message because you are subscribed to the Google Groups >> "geoengineering" group. >> To unsubscribe from this group and stop receiving emails from it, send an >> email to [email protected]. >> To post to this group, send email to [email protected]. >> Visit this group at http://groups.google.com/group/geoengineering. >> For more options, visit https://groups.google.com/groups/opt_out. >> > > -- You received this message because you are subscribed to the Google Groups "geoengineering" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To post to this group, send email to [email protected]. Visit this group at http://groups.google.com/group/geoengineering. For more options, visit https://groups.google.com/groups/opt_out.
