Geoworld Spotlight

Geologists have long known that the Earth has gone through numerous glacial advances in the last two million years and that, barring interference by human activity, an ice age would "naturally" occur again in the next 20K-50K years.

Prof Tom Crowley has recently combined data and model analyses to suggest that the increase in climate variability over the last million years may be an indication that the climate system may have been evolving to -- not just another glaciation, but permanent midlatitude northern hemisphere glaciation.

Crowley and his co-author, William Hyde from the University of Toronto, base their interpretations upon the fact that increased variability is sometimes an indicator of an unstable system ready to transition to its new stable state.

• Crowley, T. J. and W. T. Hyde (2008). Transient nature of late Pleistocene climate variability Nature 456(7219): 226-230.
• Scottish Alliance for Geosciences Environment and Society (SAGES)