Dr. Björnsson has made unique and long-lasting contributions to a broad range of glaciological problems whose roots lie partially in Iceland but whose lessons extend around the world. Among other things, Dr. Björnsson is known for his contribution to our understanding of glacier dynamics, including glacier surges, glacier hydrology and jökulhlaups (outburst floods), ice–climate interactions and glacier mass balance, glacio-volcanic processes and the development and application of radio-glaciological methods. 

Over his career, Dr. Björnsson also initiated numerous collaborations that address a range of subjects from geodetic monitoring of the cryosphere to paleo-environmental reconstruction. Dr. Björnsson is a pioneer in the use of Ground Penetrating Radar (GPR) on glaciers, not only to map glacier thickness and quantify ice volume, but also to determine and understand the internal structures of glaciers, in particular the thermal regimes and hydrological characteristics of polythermal glaciers. The resulting GPR-derived maps of subglacial topography are also important for volcanology and crustal deformation studies, as ice caps cover many of Iceland’s active volcanoes.

His achievements in glaciology led to authoritative reviews on subglacial volcanism, outburst floods and glacier surges, and have also influenced other fields of Earth science such as glacial geomorphology, paleo-glaciology, hydrology and polar environmental studies.

As Professor at the University of Iceland, Dr. Björnsson became the nation’s expert on everything glaciological, and is a frequent contributor and commentator for national and international media. He navigated this balance of pure and applied science in a manner that kept Iceland on the international scientific stage, while fulfilling the duties of public service.

As evidence of his exceptional record of public outreach, Dr. Björnsson has also contributed to the cultural history of Iceland through popular books.  Jöklar á Íslandi (published in English as The Glaciers of Iceland) received the 2010 Icelandic Literary Prize, and In the Realm of Vatnajókull – A Companion on the Southern Ring Road is an engaging and sophisticated guidebook co-authored in 2021 with his wife Thóra Ellen Thórhallsdóttir. Dr. Björnsson’s career has been an exemplar of internationally recognized and locally relevant research, marked by accomplishments that engaged and inspired multiple generations of scientists.