There is a news article in the Australian News by Leigh Dayton, (Thanks to Joseph D’Aleo for alerting us to it) entitled
“North hottest for 1500 years”
It reads
“The northern hemisphere is hotter now than at any time in the past 1500 years, according to the most comprehensive reconstruction of the earth’s temperature over the last two millenniums.
It’s likely the southern hemisphere is also warmer than ever although data is sketchier, claim US and British scientists.
While the new research also concluded that the so-called Medieval warmth from 950-1100 was hotter than previously thought, the last decade was hotter still.
“The findings deeply reinforce the incontrovertible conclusion that we are warming rapidly outside natural variability,” said climate scientist Andy Pitman, co-director of the Climate Change Research Centre at the University of NSW.
The new findings come from a team led by Michael E. Mann, director of the Environmental Systems Institute at Pennsylvania State University in University Park.
Writing in the US journal Proceedings of the National Academy of Sciences, they reported that they’d pulled together the largest ever set of climate data, enabling them to assess changes on decadal and centennial scales.
Associate Professor Mann and his colleagues used “natural climate archives” like tree-rings, corals and ice cores, along with historical documentary records and recently updated instrumental data to reconstruct the climate of past centuries in unprecedented detail and compare it with existing conditions.
“Our results extend previous conclusions that recent northern hemisphere surface temperature increases are likely anomalous in a long-term context,” they claimed.
According to Professor Pitman, the work showed clearly that despite “wiggles” of warming and cooling in the past, driven by natural variation, surface temperatures in the modern period (1961-1990) show an upward trend not triggered by solar variability or other natural processes.
He also said the report highlighted the need to obtain more southern hemisphere data. That would help scientists further refine the climate change models used to predict future conditions in regions around the world.”
This is, quite frankly, a very poor (and erroneous) news report. The data used for its construction are not temporally homogeneous (such as kludging a thermometer record on the end of a proxy temperature record) as well as ignoring the very substantial evidence of a warm bias in the surface temperature record that is summarized in
Pielke Sr., R.A., C. Davey, D. Niyogi, S. Fall, J. Steinweg-Woods, K. Hubbard, X. Lin, M. Cai, Y.-K. Lim, H. Li, J. Nielsen-Gammon, K. Gallo, R. Hale, R. Mahmood, S. Foster, R.T. McNider, and P. Blanken, 2007: Unresolved issues with the assessment of multi-decadal global land surface temperature trends. J. Geophys. Res., 112, D24S08, doi:10.1029/2006JD008229
and
Lin, X., R.A. Pielke Sr., K.G. Hubbard, K.C. Crawford, M. A. Shafer, and T. Matsui, 2007: An examination of 1997-2007 surface layer temperature trends at two heights in Oklahoma. Geophys. Res. Letts., 34, L24705, doi:10.1029/2007GL031652.
If the scientists are quoted correctly in the news release [which is always a question!], then they have failed to examine the substantive issues that have been raised with the surface temperature record. The Reporter certainly neglected to properly investigate the claims of the authors and, as a result, has presented the public with yet another biased news article on climate.