A project undertaken at the University of Melbourne, and supervised by Agathe Lise-Pronovost
Global warming is melting polar ice sheets, leading to accelerated sea-level rise. Under the IPCC’s ‘worst-case emissions scenario’, this is expected to contribute up to 1 metre of mean sea-level rise by 2100, impacting hundreds of millions of people living along the world’s coastlines, including those living in Australia’s coastal cities.
Ice-sheet models, which are used to predict the timing, volume and source region of melting, are critical for projecting future sea-level rise and, ultimately, planning adaptation pathways. However, testing and calibrating these models is challenging, largely because the length of instrumental measurements of ice sheet properties is too brief.
An alternative is to interrogate the palaeoclimate record, which contains evidence of ice-sheet responses to episodes of warm climate in the relatively recent past. The aim of this project is to determine the exact timing of ice-sheet meltwater releases from Antarctica during the Last Interglacial (130,000 – 120,000 years ago), the most recent period of excessive warmth. Evidence for ice sheet melting at this time is preserved in marine sediments in the Southern Ocean, but the time scales for marine records of this age are imprecise.
We use information from cave mineral deposits called speleothems (e.g. stalagmites) from NZ and Tasmanian sites to determine the timing of mid-latitude climate responses to ice-sheet meltwater pulses. By combining our cave data with marine sediments and ice cores, we will ultimately develop a sequence of polar meltwater events from both hemispheres.
These results will be used to test and refine the models used to predict future sea-level rise and the regional climate impacts of large-scale ice-sheet melting. Improved models will ultimately translate to better-informed adaptation strategies.