Greenland and Antarctica Lose 12.5 Trillion Tons of Ice Since 1979, Study Finds

Since 1979, the ice sheets of Greenland and Antarctica have lost 12.5 trillion tons of mass. Data published in Scientific Data, based on satellite archives from NASA and the European Space Agency, reveals a stark discrepancy between the perceived drivers of melting and the actual physical mechanisms at work.

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Global warming

The central tension in the data lies in the role of the ocean versus the atmosphere. While rising air temperatures often dominate the public narrative, the study shows that atmospheric warming is a secondary factor. Five-sixths of the ice loss is driven by warm oceanic currents eroding the sheets from below and the sides. This basal melting destabilizes the ice, accelerating the flow of glaciers into the sea. In Greenland, the Jakobshavn glacier exemplifies this speed, retreating by up to 50 meters per day.

This loss of 11.3 quadrillion liters of water has already raised global sea levels by 3.1 cm. The human cost of this measurement is significant: Ines Otosaki from Northumbria University notes that every 0.8 cm of sea-level rise correlates with the flooding of areas inhabited by 2 to 3 million people.

The timeline of the melting process highlights a dangerous lag effect. The ice sheets remained relatively stable from the 1970s through the early 1990s, with a sharp acceleration only becoming evident in the 2010s. According to Andrew Shepherd of Northumbria University, this inertia means the ice sheets are reacting to warming that occurred decades ago. Consequently, the melting is likely to persist even if global atmospheric heating were to stop immediately.

Internal contradictions within the data further complicate the picture, particularly in Antarctica. The continent's overall stability is an illusion created by a balance of opposites: record snowfall in East Antarctica is currently masking the rapid collapse of the more vulnerable West Antarctic Ice Sheet.

While measurements from 2020 to 2023 showed a temporary deceleration, researchers categorize this as a short-term weather fluctuation rather than a trend reversal. Recent data confirms the acceleration has resumed. The primary risk now shifts from gradual melting to "dynamic processes"—sudden mass shedding events that can push the system past critical tipping points, rendering the loss irreversible.