Dr Steven Palmer has led a study, published in the journal Geophysical Research Letters, that has revealed two subglacial lakes 800 metres below the Greenland Ice Sheet, which are likely to influence the flow of the ice sheet, impacting global sea level change.

The British Antarctic Survey’s Twin Otter survey plane & camp, the plane was used to collect data about the size of the sub-ice-shelf channel. Image credit Neil Ross.

Neil Ross

Dr Anne Le Brocq has been part of a group of scientists that has discovered 250 metre high ice channels beneath a floating ice shelf that will help predict future of Antarctic ice.

Glaciers are melting faster than they have for at least 350 years.

Melting mountain glaciers are contributing to sea-level rise faster than at any time in the last 350 years, according to new research carried out by Dr Stephan Harrison.

Environmental Change

Ice, sea level & climate change

Antarctic Ice Sheet reconstruction

Fluctuations in the size of the Antarctic Ice Sheet have a major influence on global climate and sea level.  The size of the ice sheet at the Last Glacial Maximum, and its subsequent deglaciation, have been investigated using numerical modelling and marine geophysical investigations.  The Weddell Sea sector of the ice sheet has the capacity for a greatly advanced ice sheet at the Last Glacial Maximum, however, field and modelling evidence has suggested that the ice sheet was not as large as previously thought at this time (Le Brocq et al., 2011).  The Pine Island Glacier is one of the major outlets for draining West Antarctic continental ice, and is currently undergoing dramatic changes. New marine surveys offshore of the glacier have framed these changes against a backdrop of long-term retreat, showing the pattern of deglaciation to the present-day (Graham et al., 2010).

Key publications:

Graham, A.G.C., Larter, R.D., Gohl, K., Dowdeswell, J.A., Hillenbrand, C.-.D., Smith, J.A., Evans, J., Kuhn, G., Deen, T. (2010). Flow and retreat of the Late Quaternary Pine Island-Thwaites palaeo-ice stream, West Antarctica. Journal of Geophysical Research F: Earth Surface, 115(3).

Le Brocq, A.M., Bentley, M.J., Hubbard, A.L., Fogwill, C.J., Sugden, D.E. (2011). Reconstructing the Last Glacial Maximum ice sheet in the Weddell Sea embayment, Antarctica, using numerical modelling constrained by field evidence. Quaternary Science Reviews, 30(19-20), 2422-2432.

Recent funding:

Dec 2012  –  Dec 2014: NERC New Investigator Award NE/K0005271 (£99,985), “Testing the extent and timing of past glaciations on the largest sub-Antarctic island, South Georgia”. Alastair Graham, PI.

Oct 2014 – Oct 2016: NERC/UK-IODP Phase2 site survey grant NE/J006548/1 (£280,880), “Depositional patterns and records in sediment drifts off the Antarctic Peninsula and West Antarctica”. Alastair Graham, Co-I.

Patagonia

The former Patagonian Ice Sheet formed the largest mid-latitude ice mass in the Southern Hemisphere during the Quaternary, its dynamics driven by the Southern Westerly wind system.  The region occupies a crucial location for resolving debates about the pace and timing of global climate change.  However, much more needs to be known about the nature of Quaternary glacial events from the Southern Hemisphere.  As a result we have produced the first detailed reconstruction of the vertical dimensions of the Pleistocene Patagonian Ice Sheet and have dated glacier fluctuations in Patagonia over a range of timescales.  We show: that contemporary glacier recession is much higher than during preceding centuries; that the pattern of glacier fluctuations during the late Quaternary was more complicated than previously believed, and that the evolution of the former ice sheet was probably driven by shifts in the core of the Southern Westerlies.

Key publications:

Boex, J., Fogwill, C., Harrison, S., Glasser, N.F., Hein, A., Schnabel, C., Xu, S. (2013). Rapid thinning of the late Pleistocene Patagonian Ice Sheet followed migration of the Southern Westerlies. Sci Rep, 3. 

Glasser NF, Harrison S, Schnabel C, Fabel D and Jansson K (2013) Early Holocene and Younger Dryas glacier advances in Patagonia. Quaternary Science Reviews, Vol. 58, 7-17.

Glasser NF, Harrison S, Jansson KN, Anderson K and Cowley A. (2011). Global sea-level contribution from the Patagonian Icefields since the Little Ice Age maximum. Nature Geoscience 4(5), 303-307.

Recent funding:

Leverhulme Research Fellowship to Stephan Harrison (2014): ‘Glacial Lake Outburst Floods and Climate Change’.

Subglacial hydrology and its impact on ice sheet behaviour

Investigations into the nature and role of water beneath the two major ice sheets, Greenland and Antarctica have been carried out using remote sensing and airborne measurements.  Using satellite derived ice velocity measurements, a link was demonstrated between surface hydrology routes and summer speed up (Palmer et al., 2011).  Channelised water flow at the margin of the Antarctic Ice Sheet has been demonstrated through the existence of linear features on floating ice shelves (Le Brocq et al., in press).

Key publications:

Le Brocq, A.M., Ross, N., Griggs, J.A., Bingham R.G., Corr, H.F.J., Ferraccioli, F., Jenkins, A., Jordan, T.A., Payne, A.J., Rippin, D.M., Siegert, M.J. (in press) Evidence from ice shelves for channelized meltwater flow beneath the Antarctic Ice Sheet.  Nature Geoscience

Palmer, S., Shepherd, A., Nienow, P. and Joughin, I. (2011) Seasonal speedup of the Greenland Ice Sheet linked to routing of surface water

Future behaviour of the Antarctic Ice Sheet

The Weddell Sea sector of the ice sheet has been recently identified as a sector of the Antarctic Ice Sheet potentially at risk of retreat due to changes in ocean conditions driven by changes in the climate.  Our research found the region to be highly sensitive to this forcing, but the degree of retreat of each ice stream was a function of the configuration of the ice stream.

Key publications:

Ross, N., Bingham, R.G., Corr, H.F.J., Ferraccioli, F., Jordan, T.A., Le Brocq, A., Rippin, D.M., Young, D., Blankenship, D.D., Siegert, M.J., et al (2012). Steep reverse bed slope at the grounding line of the Weddell Sea sector in West Antarctica. Nature Geoscience, 5(6), 393-396.

Wright A.P., Le Brocq A.M. etc Sensitivity of the Weddell Sea sector ice streams to sub-shelf melting and surface accumulation (in review) The Cryosphere.

Recent funding:

NERC AFI Grant (NE/G013071/1) “Airborne geophysical investigation targets basal boundary conditions for the Institute and Moller ice streams, West Antarctica”

Records of climate change from glaciers in the Western Pacific region

A growing database of evidence is revealing that not only did the two hemispheres respond differently to climate change during the last ice age, but that some changes were also highly regional. To study the pattern and timing of climate change in response to greenhouse gas changes and other climate forcings, we are reconstructing the history of glaciation along the Western Pacific Ocean rim. Early results reveal that glaciation in the mid latitudes was dynamic and the maximum volume of ice was reached early in oxygen isotope chronozone 2. Conversely, maximum ice extent in the tropics was attained only during the last glacial maximum when greenhouse gas concentrations were at their lowest. Ongoing work is exploring these variations and studying the magnitude of cooling during the height of the last ice age using periglacial landforms.

Key publications:

Barrows, T. T., Almond, P., Rose, R., Fifield, L. K., Mills, T. C., Tims, S. G. (2013) Late Pleistocene glacial stratigraphy of the Kumara-Moana region, West Coast of South Island, New Zealand. Quaternary Science Reviews, 74: 139-159. 10.1016/j.quascirev.2013.04.010

Barrows, T. T., G., Hope, M., Prentice, L. K Fifield, and S. Tims. (2011) Late Pleistocene glaciation of the Mt Giluwe volcano, Papua New Guinea. Quaternary Science Reviews, 30, 2676-2689.

Recent grants:

2011-2014 Co-PI Shulmeister, Barrows and others The last glaciation maximum climate conundrum and environmental responses of the Australian continent to altered climate states. (DP110103081) Australian Research Council, $527,000

2010-2013 Lead PI Barrows, Pillans Understanding global warming using long-term glacier retreat records. (DP1095053) Australian Research Council, $160,000