Unpublished letter to the Sydney Morning Herald, sent 10 May 2010.
If Penny Wong, Kurt Lambeck and David Karoly want evidence (Climate scientists cross with Abbott for taking Christ's name in vain, 10/5) to suggest it was hotter 2000 years ago, they can find just one example, of many, in a recent article titled "Holocene thinning of the Greenland ice sheet" published in Nature in 2009. The article by Bo Vinther of the Niels Bohr Institute in Copenhagen and colleagues uses oxygen Isotope data to reconstruct temperatures over Greenland through the Holocene. Not only does the Vinther data confirm the presence of the rather "toasty" Holocene Climate Optimum, it also reveals numerous warm pulses when temperatures were also higher than present. These include the Minoan Warm Period (1450–1300 BC), the Roman Warm Period (250–0 BC), discussed with students by Tony Abbott, and the Medieval Warm Period (800–1100AD) that the IPCC attempted to whitewash from history with its infamous hockey stick graph.
In developing policy to deal with future climate change Penny Wong should note that the long term temperature trend in the Vinther data is downwards.
