"We will be able to understand how water moves in and out of Greenland in the next few years," said first author Kevin Rozmiarek, a doctoral student at the Institute of Arctic and Alpine Research (INSTAAR) at CU Boulder. "As a major freshwater reservoir, we need to understand how Greenland's environment is going to change in the future."
The research, published March 14 in JGR Atmospheres, highlights the critical role of atmospheric water vapor in understanding ice dynamics. Greenland has lost ice annually for 28 consecutive years, shedding about 55 gigatons of ice and snow between fall 2023 and fall 2024 alone, according to NOAA. Since 1992, over 5 trillion tons of ice have disappeared from the island.
Holding about 8% of the world's freshwater, the Greenland ice sheet is a key player in regulating sea levels, ocean circulation, and ecosystems across the globe. While much of the loss stems from glacial calving and melting, sublimation-the direct transition of ice into vapor-may be more significant than previously thought. In some regions, as much as 30% of summer surface snow might sublimate into the atmosphere.
The fate of that vapor remains unclear. Some of it may return as snow or recondense, but a portion could leave the Greenland system entirely, Rozmiarek explained. Yet capturing air samples above the ice sheet has been a logistical hurdle, usually requiring costly aircraft operations in harsh Arctic conditions.
To bypass these challenges, Rozmiarek and colleagues deployed a drone with a 10-foot wingspan outfitted with specialized air sampling instruments. Over the summer of 2022, they conducted 104 flights from the East Greenland Ice-Core Project camp, managed by the University of Copenhagen, reaching altitudes close to 5,000 feet.
Their focus was on isotopes-unique combinations of hydrogen and oxygen atoms within water molecules-which act as signatures of origin. "Isotopes are water's fingerprints. By following these fingerprints, we can trace back to the source where the water vapor came from," Rozmiarek said. Scientists already understand much about the sources (such as tropical air masses) and sinks (like snow accumulation), but the isotopic makeup of vapor in transit has remained largely unknown.
When the team compared their measurements to an existing Arctic water cycle simulation, they discovered the model underestimated precipitation over Greenland. Integrating their new isotopic data corrected the model, improving its ability to simulate water movement over the ice sheet.
"It's really important to be able to predict what's going to happen to Greenland in the warming world as accurately as possible," Rozmiarek said. "We demonstrated how useful water vapor isotope data is by successfully improving an existing model."
The study also points to the possibility of major future changes. Around 125,000 years ago, during a warmer climatic period, Greenland's ice sheet was much smaller, and sea levels were up to 19 feet higher than today. If current warming trends continue, similar reductions in ice coverage could occur.
The ice sheet's massive volume of freshwater poses a global risk if released into oceans. The United Nations reports that rising seas due to climate change already affect around one billion people worldwide.
Rozmiarek aims to expand his research across Greenland and the broader Arctic, using drone-based observations to trace how water vapor moves through the atmosphere.
"It's like we just figured out how to discover fingerprints at a crime scene. This is a concrete step forward in understanding where water is going and where it is coming from in this important system at a time when we need it most," he said.
Research Report:Atmosphere to Surface Profiles of Water-Vapor Isotopes and Meteorological Conditions Over the Northeast Greenland Ice Sheet
Related Links
University of Colorado at Boulder
Beyond the Ice Age
| Subscribe Free To Our Daily Newsletters |
| Subscribe Free To Our Daily Newsletters |
