Is Antarctica
isolated from Anthropogenic Global Warming?
Dated 2005, a
white paper from International Partnerships in Ice Core Sciences (IPICS)
entitled “The
IPICS 2k Array: a network of ice core climate and climate forcing records for
the last two millennia” contains an interesting graphic. A couple of
horizontal lines have been added to help illustrate the point. It clearly shows
that over the last 200 years of the last millennium Antarctica temperatures have
fluctuated but that the temperatures in the late 20th century were matched in
about 1830 and 1940. There are two distinct temperature minimums at around 1865
and 1955. It is also important to note that the continent wide ice core records
do not demonstrate the same positive trend of the southern hemisphere
instrumented record.
By inspection, if
the record had been extended to beyond the year 2000, it is likely that the
apparent peak in the 1990’s, where the smoothed curve stops, would have turned
over and matched fairly closely, or possibly been lower than the other two
maxima. Bear in mind that Antarctica is a significant proportion of the Earth's
land area, being approximately double the size of Australia, half as big again
as the USA or nearly fifty times that of the UK.
Update:
Schneider
has released a paper on this work. It contains a slightly extended
graph, and indeed the late twentieth century peak does turn over and plummets.
An excellent critique can be found
here:
Here is the graphic from the paper -
Schneider, D. P., E. J. Steig, T. D. van Ommen, D. A. Dixon, P. A. Mayewski, J.
M. Jones, and C. M. Bitz (2006), Antarctic temperatures over the past two
centuries from ice cores, Geophys. Res. Lett., 33, L16707,
doi:10.1029/2006GL027057:
Now compare the continent wide Antarctic
temperature reconstruction with the accepted carbon dioxide record:
It is rather difficult to conclude that
atmospheric carbon dioxide is driving temperature.
However, Schneider et al conclude:
Interesting. It seems that peer review
missed this one.