Polar winter: A biological model for impact events and related dark/cold climatic changes

Models of the climatic perturbation caused by a large scale extraterrestrial impact predict an injection of dust into the stratosphere. This would cause the onset of environmental conditions whose two principal characteristics are a prolonged period of darkness and reduced global temperatures. Similar scenarios follow large scale volcanic eruptions, wildfires and they are predicted for a nuclear winter following a protracted nuclear exchange. A significant drop in temperature and solar insolation are also characteristics of the polar winter. In this paper the onset and emergence from the polar winter is examined as a potential biological framework for studying immediate biological effects following transition into and out of a dark/cold catastrophe. Limitations of the conceptual model, particularly with respect to the fact that polar organisms are well adapted to a regular and severe dark/cold climatic change (which the rest of the Earth's biota is not) are discussed. The model has implications for the poles as an extinction refuge during such climatic changes.