Tracking Greenland's Vanishing Ice Sheet By Satellite
By John Oncea, Editor
ESA’s CryoSat-2 and NASA’s ICESat-2 satellites track Greenland’s melting ice with precise radar and laser data, revealing rapid ice loss and aiding climate change research.
About a year ago, I wrote a story introducing GeoXO, NOAA’s upgrade to its current GEOS-R weather satellites. In it, I reminisced about cruising on a boat my grandfather helped build that was used for tours of the Thousand Islands archipelago on the St. Lawrence River running between Clayton, NY and Gananoque, Ontario.
What I didn’t mention then was that, during the cruise, the captain jokingly mentioned one of the teeniest, tiniest islands was available for $1.98. I told my mother that I wanted to buy it for her and while I don’t remember how she let me down softly about it not being a real offer, I do remember her being happy I was willing to part with two of my hard-earned dollars for her.
I was reminded of this recently when one world leader declared he wanted to buy Greenland. Sure, it’s a bigger island with a larger price tag, but I’m sure the motivation for wanting to buy it is pure as my love for my mother.
Or maybe it was because it was essential “for national security and international security,” or the natural resources buried under the ice on the world’s largest island.
According to Wired, “The melting of ice sheets in Greenland and across the Arctic is a global tragedy, but for steely policymakers in Washington, it is also an opportunity. An iceless Arctic would open up new trade routes; it would make natural resources accessible (U.S. government estimates expect 22% of the world’s natural gas and oil to be in the Arctic); and would kick-start a new era ‘for expanded great power competition and aggression,’ as declared in the U.S. Department of Defense’s 2019 Arctic Strategy.
Now, I Told You That Story To Tell You This Story
I mentioned the Greenland Ice Sheet, the single ice sheet or glacier covering about 80% of the island of Greenland and the largest ice mass in the Northern Hemisphere, globally second in size to only the ice mass that covers Antarctica, according to Britannica.
“It extends 1,380 miles north-south, has a maximum width of 680 miles near its northern margin, and has an average thickness of about 5,000 feet. The Greenland Ice Sheet extends from approximately 60° N to 80° N and thus is not in the polar zone, unlike the Antarctic Ice Sheet. The Greenland Ice Sheet is protected by cold waters of mostly Arctic origin against the temperate Atlantic waters from the southeast. In volume, it contains 12% of the world’s glacier ice, and, if it completely melted, sea level would rise 24 feet.”
The decline in the mass of the Greenland Ice Sheet has been thoroughly documented since the 1990s, with a notable acceleration in ice loss occurring in the 21st century. This reduction in ice mass is primarily attributed to a decrease in the surface mass balance of the ice sheet itself, driven by factors such as solar radiation, rising air temperatures, and changes in precipitation, along with significant losses from iceberg calving.
As melting continues, fjords are expanding, which allows warm air to reach the bases of glaciers. These developments lead to increased glacier movement, resulting in more frequent iceberg calving events. Consequently, it is estimated that the Greenland Ice Sheet has contributed approximately 0.4 inches (10.6 mm) to global sea level rise since the 1990s.
How ESA and NASA Satellites Provide Critical Climate Data
According to Northumbria University, the Greenland Ice Sheet has lost 563 cubic miles of ice between 2010 and 2023 – enough to fill Africa’s Lake Victoria. However, this masks dramatic regional variations. The ice sheet’s edges experienced much more severe thinning, losing approximately 21 feet (6.4 meters) on average. The most extreme changes occurred at outlet glaciers, with Zachariae Isstrøm glacier showing a staggering maximum loss of 246 feet (75 meters).
The ability to measure and quantify this dramatic melting is made possible by the European Space Agency’s CryoSat-2 and NASA’s ICESat-2 satellites, the former utilizing radar technology to determine surface elevation, the latter deploying a laser system called ATLAS (Advanced Topographic Laser Altimeter System), according to Daily Galaxy.
This technological diversity offers distinct advantages: CryoSat-2’s radar can penetrate clouds but requires adjustment as it also penetrates the ice surface, while ICESat-2’s laser reflects precisely from the surface but cannot operate through cloud cover, Phys.org writes.
Scientists have long sought to combine these complementary approaches, and recent research has confirmed that measurements from both satellites agree to within 3% when tracking Greenland Ice Sheet elevation changes, writes Live Science. This breakthrough in measurement accuracy enables more comprehensive and reliable monitoring of ice loss patterns.
NASA’s ICESat-2 recently achieved a remarkable milestone, firing its 2 trillionth laser pulse on March 9, 2025, at precisely 12:51 p.m. EDT. The satellite fires an impressive 10,000 laser pulses per second to build a highly detailed, three-dimensional profile of Earth’s changing surface. Despite six years of continuous operation, the laser shows no signs of degradation, suggesting it could remain operational well into the 2030s, with a backup laser ready if needed.
While ICESat-2’s primary mission focuses on measuring ice, its capabilities extend to tracking changes in forests, water bodies, and even detecting coastal seafloor topography in some regions. This versatility makes it an invaluable tool for Earth observation beyond just ice monitoring.
Synchronized Orbital Paths Enhance Data Quality
Since 2020, CryoSat-2 and ICESat-2 have been orbiting along the same paths – a joint initiative between ESA and NASA to ensure that data from both satellites can be collected simultaneously and syncronized, Space.com writes. This coordination represents an unprecedented level of international cooperation in Earth observation and climate science.
The Vanderford Glacier in East Antarctica provides an excellent example of the satellites’ capabilities. ICESat-2 data shows how the ice surface dropped about six feet between 2019 and 2022, rose slightly the following year, but then dropped again in 2024, according to NASA. This detailed temporal resolution allows scientists to track not just long-term trends but also short-term fluctuations.
Implications For Climate Science
The Greenland Ice Sheet has been losing mass since 1998 and is currently the second-biggest contributor to sea level rise after thermal expansion of ocean water. The precise measurements provided by these satellites are critical for tracking and adapting to climate change impacts.
Surface roughness is another important factor that these satellites help measure. As explained in recent research, surface roughness affects sensible and latent heat fluxes between the atmosphere and ice sheet, influencing overall surface mass balance calculations, the European Geosciences Union writes. The multi-scale measurement capabilities of these satellites provide invaluable data for refining climate models.
This collaborative satellite monitoring represents one of our most powerful tools for understanding and responding to the accelerating changes occurring in Earth’s cryosphere, offering a sobering but essential window into our planet’s rapidly changing climate system.