In four decades of satellite monitoring and field measurements, Greenland has shown a clear acceleration in ice loss driven by surface melting. New research now indicates the rate of melt is faster than earlier estimates, boosting global sea level rise projections. The finding emphasizes how the Northeast Greenland Ice Stream, which drains a vast portion of the ice cover, contributes significantly to potential future changes in ocean levels. This ice stream alone covers roughly 80 percent of Greenland’s surface area and stands as the second-largest ice reservoir on the planet, following Antarctica. Its footprint spans about 1.71 million square kilometers, stretching roughly 2,400 kilometers from north to south and up to 1,100 kilometers east to west.
New calculations suggest that the rapid melt of this sector could lift sea levels by as much as 1.5 centimeters by the year 2100. That amount approaches the Greenland contribution to sea level rise seen over the previous half-century. To reach these conclusions, an international team integrated satellite imagery with numerical modeling and GPS data collected over the past decade, forming a comprehensive view of ice dynamics in this region.
glacier in Greenland dalibor
In 2012, the entry of warm ocean currents coincided with the collapse of the floating extension of Zachariae Isstrom Glacier. That event accelerated ice flow and triggered a rapid thinning wave that moved inland from the coast.
The researchers observed thinning extending 200 to 300 kilometers inland from Greenland’s coastline, suggesting that other glaciers could face a similar fate in the future.
According to study co-author Mathieu Morlighem, a professor of Earth sciences at Dartmouth College in the United States, late-stage thinning near the coast helped sharpen the understanding that inland ice dynamics may contribute more to total mass loss than many models currently predict. This insight reflects how inland processes can feed back into the broader ice sheet, altering global sea level projections.
unexpected effect
Between 2011 and 2021, the Northeast Greenland Ice Stream’s behavior has shown substantial changes, with thinning recorded as a persistent feature. Projections indicate this pace could continue and intensify through this century, even as winter conditions vary. The lead author warned about the difficulty of stopping or reversing these trends when observed changes originate far from the ice sheet front.
Even after particularly cold winters, the Northeast Greenland glaciers continued to retreat. This region is characterized by arid conditions, with yearly precipitation well below the level needed to replenish ice, so insufficient snowfall compounds melting losses.
It remains challenging to precisely quantify total ice loss and the depth of the interior ice. The interior moves more slowly than surface regions, yet new data show that front-area observations may not capture the full extent of interior changes. As models incorporate these interior observations, estimates of global sea level rise are expected to be updated upward from prior UN projections that forecast a rise between 20 and 76 centimeters by 2100. The evolving picture underscores how detailed measurements from the central ice sheet can improve numerical models and yield more realistic forecasts of sea level rise.
Researchers emphasize that gathering precise interior observations is crucial for accurately representing the physical processes at work in large ice sheets. These findings illustrate how adding interior data to models can alter the understanding of future ocean levels.
Endnotes and citations appear in the published Nature article and support the call for continued observation and modeling to refine predictions. Additional context is provided by researchers working on Earth systems science and glaciology.
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