Vertebrate and Hominid Evolution as a Response to Climate Change
From the latest Miocene to the Holocene period, three biotic events in the large mammal communities of the western Mediterranean region show significant and robust diversity changes and/or turnover with respect to sampling, and correspond in time to significant pulses of the latest Cenozoic glaciations. The ‘Ruscinian mammal turnover pulse’ represents a major biotic event close to the ‘Messinian salinity crisis’. This can be described more as a turnover than a dispersion event. The pattern of turnover shows a significantly high value of first appearances close to the Mio-Pliocene transition; last appearances were also important but reduced significantly in the following interval. A Southern Hemisphere glaciation event has been related to the Messinian crisis. The second major biotic event corresponds to the so-called ‘Equus–elephant event’ during early Villafranchian time. The relevance of this dispersal event is proved by a marked increase in diversity as a result of a high number of first appearances. Between 3.0 and 2.6 Ma the onset of bi-polar glaciations occurred, followed by glacial–interglacial cycles of moderate amplitude sustained at the orbital periodicity of 41 ka. The last major biotic event was the ‘Galerian mammal turnover pulse’ around 1.0 Ma. This turnover represents an important community reorganization that marks a total rejuvenation of the fauna and is coincident with the arrival of Homo species in the western Mediterranean region. At this time, glacial maxima became more extreme and the dominant periodicity of variation shifted to 100 ka, which is attributed to the massive Northern Hemisphere ice sheets.
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Climates: Past and Present
The climate of the early Earth was probably very warm and has, in general, reduced since the Archean. However, it now seems that the world is about 0.6°C warmer than it was 100 years ago and estimates of the rate of global warming over the next century range from 0.16°C to 0.35°C per decade. Concurrently, global sea-level is predicted to rise from 2.4 to 10 cm per decade. These rates of change are much faster than those normally associated with the geological record, causing geologists and palaeontologists to reassess their data and their forecasts on rates of future change.
With the current interest in global climatic change and, more specifically, with global warming, it is clear that palaeontologists have valuable information to provide on the impacts of past climatic change. This volume contains papers from an international array of such geologists and palaeontologists, showing how studies of micro- and macrofossils, plant and vertebrate fossils from a range of geological ages have contributed to our understanding of how climate affects both local and more widespread areas. The contributions are arranged in geological order, ranging from the Permo-Carboniferous to the post-glacial recovery of the last 18,000 years, with an emphasis on climate change during the last two million years, particularly in NW Europe.
Climates: Past and Present will be of interest to palaeontologists, geologists and palaeoclimatologists who specialize in climatic reconstructions and any professionals enagaged in research into the geological aspects of climate change.