Project 1 - Antarctic Ice Dynamics
This project investigates past and current drivers, mechanisms and feedbacks of ice sheet retreat in order to inform projections of future ice sheet behaviour and meltwater flux.
Why this research project, and what do we plan to do?
In a warming world, the Antarctic ice sheet (the largest reservoir of freshwater on Earth) has the greatest potential to significantly raise sea levels and disrupt global ocean circulation. Yet, we don’t know how the Antarctic ice sheet will respond to changing conditions in the near or distant future. This information is also vital to underpin understanding of sea ice production, carbon sequestration, global heat uptake and influence on marine ecosystems.
New understanding is needed of Antarctica’s climate and ice sheet configuration during previous warm periods, to compare with present-day trends and predict ice sheet behaviour in a +2°C (Paris Agreement), or warmer, world.
Research Questions:
- How will marine-based ice sheets respond to a +2°C world?
- What are the local, regional and global effects of this response?
- What are the consequences of surpassing +2°C?
Research Activities:
- develop new sediment drilling technology to allow access to previous records of ice sheet dynamics in central West Antarctica
- study sedimentary records of past environmental change and ice sheet dynamics in the Ross Sea, targeting past warm intervals
- examine present-day ice sheet dynamics through detailed study of glacial and oceanographic processes
- investigate key rate determining processes of how ice-sheet behaviour depends on ocean-cryosphere-atmosphere interactions, bed topography, basal conditions, and glacial isostatic adjustment
- integrate data into numerical models to determine ice mass change under future climate scenarios
Objective 1: Previous Climate Experiments
Objective Leader: Gavin Dunbar
Goal: to enhance insight into West Antarctic Ice Sheet (WAIS) dynamics during previous intervals of warming climate.
Research Activities:
- drill into the Kamb Ice Stream to acquire new geological records from warmer-than-present interglacial episodes during the late Quaternary (past 1 million years)
- use new and existing data sets to reconstruct environmental conditions in central West Antarctica and assess variations in glacial proximity and WAIS extent through the late Quaternary
- conduct surface exposure studies to produce a chronology of past ice surface changes following the last glacial maximum to improve constraints on the pattern and rate of ice sheet retreat in the Ross Sea region
- reconstruct ocean temperatures and circulation to provide insights into the role oceanic processes during the post-last glacial retreat of the WAIS
- examine sediments of mid-Pliocene and mid-Miocene age in legacy cores to examine ice sheet response, reconstruct sea ice and determine the role of freshwater during intervals when global temperatures were 2-3°C and 3-4°C warmer than pre-industrial levels
Objective 2: Controls on Present Dynamics
Objective Leader: Christina Hulbe
Goal: to enhance knowledge of ice and ocean dynamics and determining processes within and at the margins of the Ross Ice Shelf cavity (ice sheet-ice shelf system) through the instrumental period.
Research Activities:
- employ a customised 3-D inversion algorithm capable of combining gravity data from multiple sources (airborne, oversnow, satellite) to develop a new, well constrained bathymetric model of the Ross Ice Shelf cavity
- drill through the ice sheet to access the ocean cavity and the subglacial channel to enable direct sampling of physical and chemical parameters
- deploy a long-term (multiannual) sub ice-shelf mooring to record current, temperature, salinity, pressure, and turbidity in the ocean cavity at Kamb Ice Stream’s grounding zone
- use passive and active geophysical methods) to characterise ice-ocean interaction, basal processes (including grounding zone sedimentation), and subglacial hydrology
- determine determine and characterise basal properties and processes relevant for past and future ice stream flow
Objective 3: Future Response and Projections
Objective Leader: Nick Golledge
Goal: to simulate the evolution of Antarctic ocean / atmosphere under future climate forcing scenarios to determine future response of the West Antarctic Ice Sheet and identify environmental implications for the Ross Sea Region and the globe.
Research Activities:
- adapt regional model codes to interface with the global model outputs
- deliver high spatial resolution climate and ocean outputs for the present century, under a range of possible emissions scenarios
- conduct a range of ice sheet simulations to predict ice sheet evolution over a range of spatial and temporal scales
- couple a sea ice, regional ocean, climate and ice sheet models to simulate and understand feedbacks within the ice-sheet / ocean / atmosphere system
- integrate ice sheet simulations into a gravitational / rotational (GIA) sea level model
- develop and implement novel statistical techniques to quantify uncertainties in future Antarctic ice sheet evolution
