20 May, 2012

Some inconvenient temperature data from Australia

Below is a recent bit of Warmist "research" from Australia. I guess that they hope nobody notices the figures behind their conclusions. I have always been one of those pesky people who look at the actual results in a scientific paper rather than the conclusions authors draw from their results -- and that habit is richly rewarded here.

What they actually found is quite hilarious. They found that the current temperature in the Australian region is essentially identical with the temperature in the 13th century!

To be precise, it was just nine hundredths of one degree warmer in the 20th century than it was in the 13th century. A better disproof of 20th century warming would be hard to imagine. The big surprise is that they didn't deep-six their study instead of publishing it

Journal of Climate 2012

Evidence of unusual late 20th century warming from an Australasian temperature reconstruction spanning the last millennium

Joëlle Gergis et al.

Abstract

This study presents the first multi-proxy warm season (September-February) temperature reconstruction for the combined land and oceanic region of Australasia (0°S-50°S, 110°E-180°E). We perform a 3000-member ensemble Principal Component Reconstruction (PCR) using 27 temperature proxies from the region. The proxy network explained 69% of the inter-annual variance in the HadCRUT3v SONDJF spatial mean temperature over the 1921-1990 calibration period. Applying eight stringent reconstruction ‘reliability’ metrics identified post A.D. 1430 as the highest quality section of the reconstruction, but also revealed a skilful reconstruction is possible over the full A.D. 1000-2001 period.

The average reconstructed temperature anomaly in Australasia during A.D. 1238-1267, the warmest 30-year pre-instrumental period, is 0.09°C (±0.19°C) below 1961-1990 levels. Following peak pre-industrial warmth, a cooling trend culminates in a temperature anomaly of 0.44°C (±0.18°C) below 1961-1990 levels between A.D. 1830-1859. A preliminary assessment of the roles of solar, volcanic, and anthropogenic forcings and natural ocean-atmosphere variability is performed using CSIRO Mk3L model simulations and independent palaeoclimate records. Solar and volcanic forcing does not have a marked influence on reconstructed Australasian temperature variations, which appear to be masked by internal variability.

In 94.5% of the 3000-member reconstruction ensemble, there are no other warm periods in the past 1,000 years that match or exceed post-1950 warming observed in Australasia. The unusual 20th century warming cannot be explained by natural variability alone, suggesting a strong influence of anthropogenic forcing in the Australasian region

SOURCE

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