Australia: The Land Where Time Began

A biography of the Australian continent 

Antarctic Climate Change and Environment - The Holocene

The transition from the LGM to the present interglacial period (the Holocene, beginning around 12,000 years ago) was the last major global climate change event. Geological evidence from land in the Antarctic shows that there were two marked warm periods in the Holocene, one between 11,500 - 9000 years ago, and one between 4,000 - 2,000 years ago. Some marine records show evidence of a climate optimum between about 7,000 - 3,000 years ago. These warm periods were likely to have raised temperatures by no more than around 0.5ºC. 13. The ice core record shows dramatic changes in atmospheric circulation in the Antarctic, first at 6000 years ago with strengthening of the southern hemisphere westerlies, followed at 5400-5200 years ago with abrupt weakening of the southern hemisphere westerlies, then around 1,200 years ago with intensification of the westerlies and the Amundsen Sea Low Pressure cell. 14. Links between the climates of the northern and southern hemispheres exist, but through most of the Holocene and in the prior ice age northern hemisphere climate events lagged southern hemisphere ones by several hundred years. In contrast, in recent decades the northern hemisphere signal of rising temperature since about 1850 AD has paralleled that of the southern hemisphere. Temperature change in the two hemispheres (at least as far as West Antarctica is concerned) now appears to be synchronous - a significant departure from former times, which suggests a new and different forcing, most likely related to anthropogenic activity in the form of enhanced greenhouse gases. There is no evidence in Antarctica for an equivalent to the northern hemisphere Medieval Warm Period, and there is only weak circumstantial evidence in a few places for a cool event crudely equivalent in time to the northern hemisphere’s Little Ice Age.

Sources & Further reading

  1. Turner, j., Bindschadler, R., Convey, P., di Prisco, G., Fahrbach, E., Gutt, J., Hodgson, D., Mayewski, P., Summerhayes, C., (Eds.), 2009, Antarctic Climate Change and the Environment, Scientific Committee on Antarctic Research Scott Polar Research Institute, Cambridge
Author: M. H. Monroe
Email: admin@austhrutime.com
Last updated: 11/02/2016
Home
Journey Back Through Time
Geology
Biology
     Fauna
     Flora
Climate
Hydrology
Environment
Experience Australia
Aboriginal Australia
National Parks
Photo Galleries
Site Map
                                                                                           Author: M.H.Monroe  Email: admin@austhrutime.com     Sources & Further reading