Rapid Climate Change Events During The Period Between 10ka And 50ka ( Steig )
1376 WordsMar 20, 20166 Pages
The last glacial period has encountered numerous large-magnitude, rapid climate change events; characterising the period between 10ka and 50ka (Steig, 1999). During this period was the Last Glacial Maximum (LGM), which occurred approximately 21ka, a glacial period defined by changes in greenhouse gases, sea level and ice sheets (Otto-Bliesner et al., 2006). In comparison the mid-Holocene occurred approximately 6000 years ago, during the current interglacial. The Holocene period is regarded as relatively muted in terms of ‘signals’ of climate change, with changes primarily associated with changes in seasonal solar radiance (Otto-Bliesner et al., 2006; Steig, 1999).
Models have been constructed in order to replicate the past climates, with specific reference to ‘The Community Climate System Model: Version 3’ (CCSM3), aimed to define continental scale dynamics, variability and climate change (Collins et al., 2006). With the use of models the environmental variation between the LGM and mid-Holocene periods can be construed. Roche et al (2007) refers to the LGM as the classic benchmark for models, enhanced by the use of proxy data associated with ocean surfaces, vegetation, oceanic-circulation and atmospheric conditions.
Clark et al (2009) presented the extent of the LGM, with growth of ice-sheets to their maximum extent occurring between 33ka and 26.5ka; primarily in response to climate forcing from decreases in northern summer insolation, tropical Pacific sea surface