At http://cosmictusk.com/repeat-grondine-essay-on-collapse-of-roman-empire/ the url says it all, the end of the Roman Empire and the descent into a cold wet phase of northern European climate – but what else was going on? Grondine focusses on barbarian migrations, volcanoes, earthquakes, plagues, aurora, comets, famine and fireballs etc. He claims there are 3 texts from sub Roman Britain and Gaul that refer to the destruction of Bazas in Gaul in 580AD – by a small impactor, or fireball exploding in the atmosphere. For example one of the texts is that of Adomnan's Life of St Columba, who lived from early 6th century until the 590s and many strange miracles are associated with his life. Grondine homes in on the 580s and early 7th century as a time of strange portents, earthquakes, floods and tsunamis, and other activity – and this actually leads up to Mohammad and the appearance of Islam on the world stage. Meanwhile, in western Europe, the strange things going on led to the establishment of Christianity – not only as a religion but as a powerful political force. George Howard hopes to start up a debate on what caused the low growth tree ring events at 536 and 541AD. Baillie says it was cosmic but Keys said it was a volcano. More recently, two people well known in the climate science community have chipped in by rejecting the ideas of Baillie and saying it was a volcano. This is important for climate science as volcanoes are capable of injecting large amounts of C02 into the atmosphere, and many such volcanoes have occurred in the past. If climate models take account of volcanoes and not of cosmic intrusions they would have to alter their models to compensate as the Little Ice Age was to some extent caused by an opaque sky that inhibited the amount of sunshine reaching the surface of the earth. This is not recognised generally, or only the known volcanoes, but if a lot of meteoric dust and debris in the upper atmosphere was also at play, as Korean evidence appears to indicate, this would cause climate scientists a problem – if it happened a couple of hundred years ago it could also have happened on numerous occasions in the past. Also, Baillie is on record as saying that tree ring proxies are useless as temperature markers in the past as trees are affected by all kinds of things, especially moisture and precipitation levels. In contrast, Larsen and Briffa have used tree rings as proxy data for temperature in the past. Briffa has also been involved in some peculiar collation of data in the hockey stick type modelling process, using a few trees from a remote forest in Siberia that completely contradicted data from the same forest obtained by Russian scientists. He also featured in the Climategate emails.
Now, George Howard is keen to set up a forum on the 6th century AD events – or series of events as we see in what happened a parallel with the Little Ice Age, which also involved strange goings on in the sky and religious fervours. However, in the Late Roman Period sea levels rose dramatically, which did not happen in the LIA. In fact, sea levels have been almost constant since the Tudor era, with very little erosion in contrast to the situation in the period prior to the Tudors.