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Victoria University Antarctic Research Expedition Science and Logistics Reports 2004-05: VUWAE 49

1 Popular Summary of Scientific Work Achieved

page 1

1 Popular Summary of Scientific Work Achieved

Unprecedented changes are occurring in the Earth's climate. The 1990's were the warmest decade in the last 2000 years and average global temperature is projected to rise between 1.4°C and 5.8°C by 2100 [IPCC, 2001]. Although the scientific evidence of global warming is now widely regarded as incontrovertible, predicting regional impacts is proving more problematic. Especially, conclusions of the Southern Hemisphere record are limited by the sparseness of available proxy data at present [Mann and Jones, 2003].

While meteorological records from instrumental and remote sensing data available display the large intercontinental climate variability, the data series are insufficient to infer trends or to understand the forcing, which renders prediction difficult [Jones et al., 1999; Mann and Jones, 2003]. The long ice core records from the Antarctic interior and Greenland revolutionised our understanding of global climate and showed for the first time the occurrence of RCE (Rapid Climate Change Events) (for review e.g. Mayweski and White [2002]). To understand the drivers and consequences of climate change on timescales important to us humans, a new focus of ice core work is now moving to the acquisition of 'local' ice cores that overlap with and extend the instrumental records of the last 40 years back over the last several thousand years.

This has been a key motivation behind the US-led International Transantarctic Scientific Expedition (ITASE) of which New Zealand is a member. The NZ ITASE objective is to recover a series of ice cores from glaciers along a 14 degree latitudinal transect of the climatically sensitive Victoria Land coastline to establish the drivers and feedback mechanism of the Ross Sea climate variability [Bertler et al., 2004; Bertler and 54 others, in press; Bertler et al., in press-a; Bertler et al., in press-b; Mayewski et al., in press; Patterson et al., in press]. Furthermore, the ice core records will provide a baseline for climate change in the region that will contribute to the NZ-led multinational Latitudinal Gradient Project as well as providing a reference record for the NZ-led ANDRILL objective to obtain a high-resolution sedimentary archive of Ross Ice Shelf stability.

During the 2004/05 field season one shallow and two intermediate length ice cores (21m, 180m and 200m) have been recovered from Windless Bight, Evans Piedmont Glacier, and Mt Erebus Saddle, respectively. The drilling activity was complemented by in-situ measurements of crystal morphology, density, and borehole temperature. High resolution snow samples were collected at Evans Piedmont Glacier and Mt Erebus Saddle. A weather station was installed at Evans Piedmont Glacier for a 2 year deployment. Furthermore, Victoria Lower Glacier, the first ice core site of this programme has been revisited to maintain the longer-term mass balance measurement time series, which commenced in 1999.