Australia: The Land Where Time Began

A biography of the Australian continent 

Climate Change Science – Land Temperatures – Boreholes

A global temperature reconstruction using temperatures that were measured from boreholes was begun and maintained by The Geothermal Laboratory of the University of Michigan (UM), and has also been maintained by the NCDC. The underground temperature measurements in the UM study were examined from a database of more than 350 boreholes located in eastern North America (116), central Europe (98), Southern Africa (86) and Australia (58). The scientists have found by this approach that the 20^th century was the warmest of the past 500 years, which confirmed the results of the temperature studies.

To generate the borehole reconstructions the geophysical methods used do not permit annual or decadal resolution, only the century-scale temperature trend over the last several centuries. This record, however, that is totally independent of data and methods used in other studies, shows that the Earth has been warming dramatically for some time.

It is indicated by a composite temperature history from 358 borehole sites from around the world that was obtained by the UM scientists that the mean temperature of the present day is on average 1.0^oC warmer than it was 500 years ago. In the 20^th century alone the temperature change has been about 0.5^oC, equalling the cumulative change inferred for the previous 400 years. In the time interval of overlap the composite meteorological record for the sites, where available, shows similar trends.

Farmer et al. say more information on land temperatures from the boreholes is available on:

http://www.ncdc.noaa.gov/paleo/paleo.html

Sources & Further reading

1. Farmer, G. Thomas & Cook, John, 2013, Climate Change Science: A modern Synthesis, The Physical Climate Vol.1, Springer Dordrecht