Poster's note : 3 years old, but directly relevant, and hasn't made the list yet. I've recently posted some later analyses to the list which may supercede some of the core analysis referred to in this paper.
http://onlinelibrary.wiley.com/doi/10.1002/wcc.76/abstract Abstract Of the natural forcings causing short-term climatic variations, volcanism, along with its climatic impact, is perhaps the best understood. The primary net result of the impact is the reduced receipt of solar energy at Earth's surface due to the scattering of incoming solar radiation by secondary sulfate aerosols formed from volcanic sulfur. The quantitative effects can be measured in energy-balance-based climate models, which require validation using high-quality paleoclimatic and paleovolcanic data. An important advancement in the effort to understand the role of volcanism in climate change in the recent decade is the significant improvement in paleovolcanic records from polar ice cores, represented by long records with unprecedented temporal accuracy and precision, and by the potential to identify climate-impacting stratospheric eruptions in the records. Other improvements include (1) the investigation of long-term relationship between eruptions (including super-eruptions) and climate variations, beyond an eruption's radiative impact of up to a few years; (2) a better understanding of the response to volcanic perturbation of feedback mechanisms in the climate system; and (3) the limited role of volcanic eruptions in the era of human-induced greenhouse warming. Urgent research/investigation is needed to evaluate the geoengineering proposition to counteract greenhouse warming by injecting sulfur dioxide into the stratosphere, which is based on the significant cooling effects of stratospheric volcanic eruptions, and its serious unintended consequences. WIREs Clim Change 2010 1 824–839 DOI: 10.1002/wcc.76 -- 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 geoengineering+unsubscr...@googlegroups.com. To post to this group, send email to geoengineering@googlegroups.com. Visit this group at http://groups.google.com/group/geoengineering. For more options, visit https://groups.google.com/groups/opt_out.