A important paper published today in the Journal of Geophysical Research finds that large quantities of ozone [O3], a "major greenhouse gas," are being produced naturally by an increase in lightning activity "caused by the influx of aerosols from a volcano." According to the authors, "Our findings thus suggest a stronger O3 historical radiative forcing because this link implies lower lightning-generated [nitrous oxide] and lower O3, especially in the upper troposphere, in preindustrial time. Aerosol forcing therefore has a warming component via its effect on O3 production and this component has mostly been ignored in previous studies of climate forcing related to O3 and aerosols." Prior research has shown that large variations in solar UV activity also control ozone production and that ozone levels could be the main driver of recent climate. Once again, natural variability including changes in ozone, solar and volcanic activity have been shown to be important drivers of clmate.
JOURNAL OF GEOPHYSICAL RESEARCH, doi:10.1029/2012JD017723
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