At http://cosmictusk.com/university-of-chicago-nanodiamonds-prove-cosmic-im… … which is a reference to the recent Younger Dryas event. The same story is at http://wattsupwiththat.com/2014/09/11/microscopic-diamonds-suggest-cosmi… … where the first comments become somewhat heated. However, the very first comment is somewhat reflective in that it says that if you ignore the Younger Dryas event the warming after the Ice Age is a straight line right into the Holocene (at 11,500 years ago). In otgher words, the Younger Dryas is an abberation. What does that mean?
However, the Younger Dryas event was not universally cold but it does appear to have included a return to glacial like conditions. Glaciers reformed in parts of the Scottish Highlands. However, temperatures fluctuated. It was never warm, as such, but it was not always bitterly cold. Why might that be? Was the axis of the Earth wobbling – or did the Earth encounter a cloud of stellar dust that created a temporary opaqueness in the upper atmosphere. The effects of a cosmic event such as an atmospheric explosion don't seem capable of creating 1300 years of cool weather – a sort of super Little Ice Age.
The comments at Watts Place are interesting in some respects especially when discussing the extinction of some species of large mammals – both herbivores and carnivores. Nobody quotes Earth in Upheaval or visualises a massive kill off – it is always just big enough for humans to accomplish by overkill. No mention of herds of horses buried in sediment or the mountains of bones on the Arctic Ocean perimeter. Instead, we are fed the idea that human hunters using big Clovis points were capable of doing the deed – killing off the large mammals. The situation in Australia is cited, humans arriving around 50,000 years ago and a major extinction of large faunal species occurring at around 40,000 years ago, while in N America humans appeared at the end of the Ice Age, around 17,000 years ago, and large mammals were decimated shortly thereafter. What they fail to say is that even larger numbers of big mammals died out around 40,000 years ago in N America – when humans were not there.