Geoffrey Boulton explaining the history of ice sheet research over the past 50 years

Geoffrey Boulton explaining the history of ice sheet research over the past 50 years

Geoffrey Boulton (The University of Edinburgh, Edinburgh)
Richard Hindmarsh (British Antarctic Survey, Cambridge)

Why is it important to understand ice sheet dynamics?

Through understanding the behaviour of present ice sheets, we can start to develop important insights into how these major ice masses respond to changing climate conditions. Ice sheets also contain very valuable records (as demonstrated through ice core analysis) of how these ice masses responded to climate changes in the past, over Quaternary timescales. It is important to test the long-term behaviour of ice sheets, so that we can seek answers to questions such as:

  • Do recent ice sheet dynamics reflect the full range of dynamics that ice sheets are capable of? Or have been capable of in the past?
  • Does evidence from former ice sheets reveal behaviour that is not seen in modern glaciers?

The sheer size of ice sheets also means that their behaviour can contribute to feedback mechanisms within the Earth system. If we can understand how ice sheets behave, we can also begin to make more robust projections of future environmental change.

What have been the major developments in ice sheet research?

There has been a long history of ice sheet and glacial research, going back to the development of glacial theory by Louis Agassiz in the 1800s. While the early work focused on glacial processes, it wasn’t until the work of Albrecht Penck and Eduard Bruckner in the early 1900s that scientists began to develop a more coherent idea of the timing of glacial phases. After several decades of glacial exploration, in the 1940s glaciology emerged as a distinct science. This focused along three main lines of investigation, each pioneered by a key glaciologist:

  • John Gleninvestigating the idea of ice as a plastic solid
  • John Nyeinvestigating the form and flow of ice masses
  • Gordon Robinexploring the thermal regime of ice masses

By the 1970s-80s, scientists had begun to reconstruct the behaviour of former ice sheets, using our understanding of flow dynamics, for example developed through Nye’s theories. New technologies, such as satellite imagery and ice sheet sounding, meant that scientists cold develop a detailed picture of ice sheet behaviour. These monitoring techniques could be combined with computer modelling of past, present, and future ice behaviour, to test our understanding of ice sheet dynamics. Advances in ocean and ice sheet drilling also meant that the Quaternary ice sheet record could be placed into a wider context of long-term climate change through assessing ocean-cryosphere interactions. Importantly, advances in satellite imagery/remote sensing techniques, allowed scientists to appreciate the spatial variations in ice sheet characteristics, by establishing changes in ice flow velocity and thermal properties, for example.

Over the last few decades, advances in NEXTMAP imagery and swath (submarine) bathymetry, has allowed researchers to identify geomorphological evidence of former ice sheet extent during the Pleistocene. This means that changes in ice-sheet characteristics at the present-day can be analysed within a longer-term context of cryospheric change.

Geoffrey Boulton's key questions we will be asking in the future

Geoffrey Boulton highlights the key questions that climate scientists will be tackling in the future

What are the major challenges?

To build upon the existing basis of ice sheet dynamics, future research will focus along several key lines of enquiry:

  • Remotely-sensed imagery will be increasingly important for testing our understanding of ice sheet behaviour. It is only by taking such broad-scale views that we can effectively confirm the relationships between ice sheet processes and the resulting landforms.
  • The last two decades or so have seen a major advancement in our understanding of the basal topography of Antarctica (which refers to the landscape that is being created under the thick Antarctic ice sheet). Radar evidence has demonstrated that this zone is highly dynamic, and not static and frozen over. It is characterised by ice plumes and reorganisation of the ice at the base of the ice sheet. Continued use of these advanced monitoring techniques will allow us to investigate this zone in more detail.
  • Recent focus has also been placed on the rate of change of surface elevation in Greenland and Antarctica, due to surface melt (downwasting). It is important to establish the impacts that large scale melting will have on sea level, and how this has played out in the past through analysing Quaternary records.
  • In addition to using past and present records to understand long-term changes, we also need to consider how past processes have impacted on current dynamics, and may impact on future ice sheet behaviour. Ice sheets have very long memories (ice core records, which use layers in the ice, span the last 800,000 years). It is important to maximise the knowledge that we can glean from these archives, to better understand ice sheet changes.