What the new map shows
According to the dataset, the Greenland Ice Sheet covered about 1.73 million square kilometres in 2022, about five times the size of Germany. The total length of the ice margin is approximately 53,000 kilometres, longer than Earth’s circumference, and more than 19,000 nunataks have been mapped within the ice-sheet interior. The ice mask also distinguishes between land-terminating ice and glaciers that terminate directly in the ocean – a key distinction for understanding ice dynamics and contributions to sea-level rise.
Future work should aim to systematically compare the newly derived ice mask with earlier products to show changes over time, Gregor Luetzenburg points out. However, earlier masks were generated using different data sources and methodologies, meaning that a direct comparison would largely capture methodological differences rather than genuine changes in ice-covered area.
“Developing approaches to level out these methodological differences is therefore an important next step and remains high on the research agenda,” he says.
Why does the ice margin matter?
An ice sheet outline like the one in the ice mask defines the boundary between ice-covered and ice-free terrain. These boundaries are fundamental inputs for climate and ice-sheet models, estimates of sea-level rise and studies of how meltwater flows from glaciers into the ocean.
Many widely used ice masks for Greenland are still based on satellite imagery from the 1990s or early 2000s. That is increasingly problematic, as the ice sheet has retreated substantially since then.
“When new measurements are combined with outdated ice margins, you risk introducing hidden biases into your analyses,” Luetzenburg explains. “This new dataset is designed to avoid exactly that.”
Open data – and updates to come
The PROMICE-2022 Ice Mask is openly available and distributed in several formats, making it suitable for both detailed satellite analyses and large-scale ice sheet and climate models. The researchers expect future updates as new satellite data become available.
“This is not a final product, but a new reference point. If we want to track how the Greenland Ice Sheet evolves in a warming climate, we need to keep our baseline data up to date,” says Luetzenburg.