[11] His research interests focus on glaciology, and he employs geophysical techniques to assess the flow and shape of ice sheets today and in the past.
[14] Siegert's work involves the study of large ice sheets in the past, at present and in future, using combinations of numerical modelling, satellite observations and glacier geophysical measurements.
[15] In 1996, he was part of the Russian-UK team that published an article in Nature revealing subglacial Lake Vostok in East Antarctica to be over 500 m deep.
[12] He was the PI of a NERC-funded airborne geophysics campaign to the Weddell Sea sector of West Antarctica (2009-2013), which showed the grounding line of Institute Ice Stream to be perched on a steep reverse sloping bed.
[citation needed] In December 2012 he led a NERC-funded attempt to sample Lake Ellsworth using a purpose built clean hot-water drill and water-sampling/measuring probe.