The Ross Ice Shelf, Earth’s largest ice shelf, extends across a significant portion of Antarctica. Located at the head of the Ross Sea, this immense floating ice mass is a prominent feature in the polar region. Understanding this vast ice formation provides insight into the dynamic processes occurring in Earth’s polar environments.
Defining the Ross Ice Shelf
The Ross Ice Shelf is a vast, floating platform of ice covering approximately 472,000 to 520,000 square kilometers, roughly the size of France or Texas. This structure floats on the Ross Sea, extending nearly 950 kilometers inland into the heart of Antarctica. The shelf’s thickness varies, ranging from about 330 meters near its northern edge to over 700 meters in its southern regions, and can reach up to 1,200 meters away from the floating edge.
The ice shelf forms as glaciers flow from the East and West Antarctic Ice Sheets, carrying ice and snow accumulation from the land out over the ocean. This continuous flow of ice, moving 300 to 1,000 meters per year, contributes to the shelf’s mass. The seaward edge of the shelf, known as the ice front or “barrier,” is a nearly vertical wall of ice stretching about 800 kilometers long. This ice front can rise between 15 and 60 meters above the ocean surface, with approximately 90 percent of the ice submerged below the waterline.
Its Global Importance
The Ross Ice Shelf serves as a natural buttress, slowing the flow of ice from the West Antarctic Ice Sheet (WAIS) and East Antarctic Ice Sheet (EAIS) into the ocean. This buttressing effect helps regulate global sea levels. The WAIS alone holds enough ice to potentially raise global sea levels by approximately 5 meters if it were to melt entirely, highlighting the shelf’s role in preventing this contribution.
The region around the Ross Ice Shelf is also ecologically important, supporting a diverse array of marine life. The Ross Sea and its adjacent waters provide a habitat for various species, including krill, fish, seals, and penguins. This area is home to over 30 percent of the world’s Adélie penguins, approximately half of the Ross Sea orcas, and a quarter of all emperor penguins. The shelf’s presence influences ocean currents and nutrient distribution, contributing to the high productivity of the Ross Sea ecosystem.
Beyond its physical and ecological roles, the Ross Ice Shelf is a site for scientific research. Scientists conduct studies in glaciology, oceanography, and biology to understand the complex interactions between the ice, ocean, and atmosphere. Research here helps to reconstruct the shelf’s history, assess its response to past climate changes, and investigate unique ecosystems thriving beneath the ice.
Monitoring Changes and Future Outlook
The Ross Ice Shelf is generally considered stable compared to other Antarctic ice shelves, but it undergoes continuous natural processes. These include calving, where large tabular icebergs break off from its front, such as Iceberg B-15 in 2000 and C-16 in 2006. Smaller-scale calving events also occur due to wave erosion and stresses at the ice front. The shelf also experiences basal melting, which is the melting of ice from its underside due to interaction with ocean water.
Scientists employ various methods to monitor the Ross Ice Shelf’s dynamics. Satellite imagery provides broad views of changes in its size and the occurrence of calving events. Ice core drilling allows researchers to study the internal structure of the ice, and hot-water drilling enables access to the ocean cavity beneath the shelf to measure water properties and marine life.
Monitoring Techniques
Seismic surveys
Airborne radar
Deployment of sensor floats
Autonomous underwater vehicles
While the Ross Ice Shelf has demonstrated relative stability, research indicates that warmer ocean currents are accelerating melting beneath parts of the shelf. Studies suggest that even minor ocean warming could lead to changes in the shelf’s behavior, potentially weakening its buttressing effect. Continued research is important to understand these dynamics and their broader implications for global sea levels and the Antarctic environment.