Brains
The Malaspina Glacier in southeastern Alaska is so massive that its ice spreads across the coastal plain like pancake batter—but new NASA analysis shows it behaves less like a frozen slab and more like a living, pulsing system. Using millions of satellite images collected between 2014 and 2022, NASA scientists have discovered that glaciers around the world speed up and slow down in seasonal rhythms that resemble a giant heartbeat, with Malaspina offering one of the most dramatic examples anywhere on Earth.
Malaspina, the planet’s largest piedmont glacier, flows out of the Saint Elias Mountains and fans out across lowland terrain. Though it appears nearly motionless to the naked eye, NASA’s new global analysis shows it consistently surges in spring and eases back into a crawl by winter—a pattern that repeats year after year.
The research, led by glaciologists Chad Greene and Alex Gardner at NASA’s Jet Propulsion Laboratory in California, analyzed subtle glacier motion using optical and radar satellite images. Their findings were published in November 2025 in the journal Science. For decades, scientists have studied seasonal changes in glacier speed, but typically only at individual sites or within specific regions. This new work marks the first time seasonal glacier motion has been mapped comprehensively across the globe at high resolution.
“Earth has over 200,000 glaciers, and we’re watching all of them closely,” Gardner said. “It’s no surprise that with this much data, a pattern started to emerge.”
How NASA Measured the Planet’s Glacier Pulse
NASA scientists tracked glacier speed by following the movement of surface features such as deep crevasses and debris fields—distinctive patterns that act as natural fingerprints. Those fingerprints were analyzed with an algorithm developed at JPL as part of the ITS_LIVE project, which maps global ice flow. By comparing image sequences month by month, researchers could detect when glaciers subtly accelerated or slowed under seasonal warming.
The timing of these speedups is closely tied to meltwater. As spring warmth arrives, water from surface melting drains down through cracks and reaches the glacier bed. That water acts like a lubricant, reducing friction between the ice and the ground and allowing the glacier to slide more easily.
“Glaciers are like rivers of ice that flow down mountains toward the sea,” Greene said. “When warm air melts the upper surface of a glacier, all that meltwater can make its way down to the base of the ice and act like a lubricant, causing the glacier to speed up.”
On Malaspina Glacier, NASA imagery shows red zones of high velocity expanding across the glacier each spring as meltwater pressure builds beneath the ice. By late summer, as larger drainage channels form under the glacier and pressure drops, friction increases and the ice slows again—completing one full seasonal pulse.
A Global Rhythm
While Malaspina’s spring surge is striking, the study revealed that glaciers around the world respond to seasonal warming in different ways. In Alaska, glaciers typically move fastest in spring. In the Arctic regions of Europe and Russia, peak speeds usually come later, in summer or early fall. On Baffin Island in Canada, the Barnes Ice Cap—one of the last remnants of the ancient Laurentide Ice Sheet—shows a classic summer acceleration pattern, barely moving most of the year before suddenly surging when meltwater finally arrives.
In Pakistan’s Karakoram range, the massive Baltoro Glacier behaves differently still. There, speedups begin high on the glacier and slowly propagate downstream as the melting season unfolds. Together, these varied patterns form what NASA scientists describe as a planetary-scale set of glacier pulses—distinct rhythms tied to geography, elevation, and climate.
A Vital Sign For The Planet
Beyond visual impact, the seasonal pulse of glaciers serves as a vital sign for long-term ice health. The team found that glacier flow accelerates with every degree of warming and that seasonal speed patterns are tightly linked to longer-term glacier change. Spring and summer speedups, the researchers say, can act as early warning indicators of how resilient or vulnerable a glacier may be as global temperatures rise.
“We wanted to check the health of Earth’s glaciers, so we measured their pulse,” Greene said. “Now we just need to keep an eye on their temperature.”
NASA scientists say continued satellite monitoring will be critical for predicting future sea-level rise and understanding how glaciers across different climate zones respond to ongoing warming. For Malaspina Glacier, the imagery now makes one thing unmistakably clear: what appears frozen and silent from a distance is, in reality, beating with seasonal motion—one of the clearest glacial heartbeats ever recorded on Earth.
