From ABC News in Science, 22 April 2013:
Average temperatures around the world in the last thirty years of the 20th century were higher than any other time in nearly 1400 years.
That’s the conclusion of the first climate reconstruction to examine global climate change from a regional perspective by an international network of climatologists known as the PAGES 2k network.
Their findings, based on climate data from eight continental scale regions, including Australasia, Europe, North and South America, are published today in Nature Geoscience .
The data, which was derived from sources such as tree rings, glacier ice, pollen and corals, showed all regions except Antarctica experienced a long-term cooling trend that reversed abruptly in the 20th century.
“Excluding Antarctica, the 20th century average temperature among the six regions was about 0.4°C higher than the averaged temperatures of the preceding five centuries,” write the authors.
“Compared to the preceding five centuries, 20th-century warming in the four northern hemisphere regions was, on average, about twice that of the more strongly ocean-dominated regions of Australasia and South America (about 0.5°C compared with 0.2°C), with the greatest differences at northern high latitudes.”
This is the first major effort to examine regional climate variability over the past two thousand years, says co-author and paleoclimatologist Dr Steven Phipps.
“Previous understanding of changes over this period have been based largely on the northern hemisphere because that’s where most of the records are and that’s where most of the scientists are, but what we’re doing here is extending it to the southern hemisphere as well,” says Phipps, research fellow at the University of New South Wales. Read more here.