Future plans and strategy of IODP drilling in Antarctica and the Southern Ocean


Contact
Karsten.Gohl [ at ] awi.de

Abstract

The International Ocean Discovery Program (IODP) states in its current IODP Science Plan for 2013-2023 that the polar regions are one of the primary target areas for scientific drilling using the drill vessels Joides Resolution and Chikyu as well as various drilling options in so-called Mission-Specific Platforms. In particular this is expressed in the Science Plan’s Key Theme “Climate and Ocean Change” and its Challenge 1 “How does Earth’s climate system respond to elevated levels of atmospheric CO2” and Challenge 2 “How do ice sheets and sea level respond to a warming climate”: The response of ice sheets to a warmer climate can be reconstructed from sedimentary records of relatively recent interglacial episodes when ice extent was similar, or slightly less than at present, and from much earlier times (34 - 3 Ma) when climate was several degrees warmer than today. Analysis of recently recovered ocean sediment cores suggests that the West Antarctic Ice Sheet (WAIS), with a potential of 4 m sea level rise, is particularly sensitive to climate change and may have collapsed many times over the last 5 million years. Estimates of sea level rise during warm intervals about 3 million years ago suggest the possibility of even larger changes. The Greenland Ice Sheet and WAIS together account for only about 12 m of potential sea level, so estimates greater than 12 m imply a significant loss of ice from the much larger East Antarctic Ice Sheet, containing the equivalent of about 52 m of sea level. Some of the major questions to be urgently addressed are: Did large sections of the West and East Antarctic Ice Sheets collapse the last time when atmospheric CO2 levels reached 400 ppm? What are the time spans over which past ice sheet collapses occurred, and how much warming was required to push them past their “tipping points”? To answer these questions, sediment cores are needed from the Antarctic shelves and slopes where sediment accumulates rapidly. This information is needed, along with land-based records, to constrain numerical ice sheet models that attempt to predict how ice sheets melt under warmer conditions. Drilling of continental rise and deep-sea sediments at sites close to past ice sheets will provide more direct information regarding regional ice melt history and the timing of ice advance and retreat. Ultimately, the combination of these ice-proximal and ice-distal data with modelling techniques can be used to work out the relative contributions of different ice sheets to past sea level change, providing more realistic scenarios for testing predictive models and a better understanding of ice sheet behaviour in climate change situations. The general drilling strategy in IODP is to target locations ranging from polar seas to low-latitude upwelling zones to explain the behaviour of the climate system during past episodes of global warmth. This is well in line with the SCAR-PAIS approach to development of “ice-to-abyss” data transects, extending from the ice sheet interior to the deep sea in order to link ice core, ice sheet-proximal, offshore, and far-field records of past ice sheet behaviour and sea level, yielding an unprecedented view of past changes in ice sheet geometry, volume, and ice sheet-ocean interactions. About 10 drilling proposals for Antarctica and the Southern Ocean, at various stages from pre-proposals to revised and mature full proposals, are currently in the IODP evaluation and implementation system. Some have been forwarded to the Facility Boards for scheduling, and one proposal is already scheduled for drilling. This presentation will give an overview of these proposals and their progress stages, also with regard to the future perspectives and challenges of IODP, and will discuss strategies that may help successful proposals to be considered for drilling.



Item Type
Conference (Invited talk)
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Primary Division
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Peer revision
Not peer-reviewed
Publication Status
Published
Event Details
XII International Symposium on Antarctic Earth Sciences (ISAES), 13 Jul 2015 - 17 Jul 2015, Goa, India.
Eprint ID
37939
Cite as
Gohl, K. (2015): Future plans and strategy of IODP drilling in Antarctica and the Southern Ocean , XII International Symposium on Antarctic Earth Sciences (ISAES), Goa, India, 13 July 2015 - 17 July 2015 .


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