At http://blog.mysciencework.com/en/2012/06/19/new-evidence-for-climate-cha… …. is an overview of the YDB event hypothesis and its detractors – and the nature of the dispute between those who favour a cosmic impact of some kind and those who are opposed to such an idea, preferring the ocean circulation hypothesis. Note that the idea of solar activity, or a downsizing of solar activity, is not part of the debate – here, at least. The blog post of Abby Tabor is good as it provides direct links to a number of papers central to the debate and readers can evaluate the situation for themselves without overt direction towards one side or the other. It also notes that lightning, another source of high temperatures, produce similar objects known as fulgarites. Yet there is supposed to be no known mechanism, as accepted in the consensus paradigm, for distributing fulgarites over a wide area such as found with SLOs, particles of melted silica grains. One of the problems is that the detractors insist on criticising by way of an impact event rather than a more nuanced situation akin to the Clube and Napier model. They probably feel it is easier to shoot down the impact hypothesis, or muddy the waters, as we are basically dealing with people who just do not wish to embrace catastrophism – of any kind. The concept of heavy meteoric activity is just ignored and the criticism is always aimed at actual impacts, and lack of craters etc.
George Howard accuses the anti-impact scientists of being disingenious with the evidence, as if impacts cannot cause a change in climate. The same people have no problem with the idea of nuclear war causing a cosmic winter (a nuclear winter) and yet a succession of tunguska like explosions is many times more powerful than human-made nuclear bombs. At http://cosmictusk.com/another-informative-blog/ George Howard also addresses the length of the Younger Dryas climatic downturn, providing his view of how it might have come about and what might have happened to bring it to an end – an interesting idea.