Thwaites Glacier Melting: New Robot Data Reveals Alarming Trends

Scientists have long monitored the Thwaites Glacier in West Antarctica due to its massive size and precarious position. However, recent data retrieved by a specialized underwater robot has shifted the scientific understanding of how this ice shelf is deteriorating. The data reveals that warm ocean water is infiltrating deep cracks and crevasses beneath the glacier, causing it to melt faster and more unpredictably than previous models projected.

The Icefin Mission and Grounding Line Discovery

The primary source of this new data comes from “Icefin,” a pencil-shaped underwater robot developed by a team including scientists from Cornell University and the British Antarctic Survey (BAS). To reach the water beneath the glacier, the research team drilled a borehole through nearly 2,000 feet (600 meters) of ice. Icefin was then deployed to explore the “grounding line,” which is the critical point where the glacier rests on the seabed before floating out over the ocean as an ice shelf.

The findings from this mission, published recently in the journal Nature, provided a detailed look at the glacier’s underbelly. While the overall melting rate in flat areas was slower than estimated, the robot discovered a complex process occurring in the structural weak points of the ice.

The Mechanism of Crevasse Melting

Icefin captured images and data showing that warm, salty ocean water is forcing its way into natural cracks, crevasses, and terraces (staircase-like formations) in the ice base. This creates a feedback loop:

• Intrusion: Warm water enters a crack.
• Melting: The water melts the sidewalls of the crack, widening it.
• Turbulence: The mixing of fresh meltwater and salty ocean water creates turbulence, which pulls in more warm water.

This “vigorous melting” inside the cracks is compromising the structural integrity of the glacier from the bottom up. Lead scientist Britney Schmidt described the process as warm water “funneling” into these weak spots, which acts almost like a knife slicing through the ice shelf.

Understanding the "Doomsday Glacier" Nickname

Thwaites is frequently referred to as the “Doomsday Glacier,” a dramatic title that underscores its potential impact on global geography. The glacier is roughly the size of Florida or Great Britain and is the widest glacier in the world, spanning about 80 miles (120 km). Its collapse would have significant consequences for global sea levels.

The “Cork in the Bottle” Effect

Thwaites acts as a natural dam or keystone for the much larger West Antarctic Ice Sheet. It blocks a vast amount of ice behind it from flowing into the ocean. If Thwaites were to collapse or dissolve, it would be like popping a cork from a bottle.

• Direct Impact: The collapse of Thwaites alone could raise global sea levels by approximately 2 feet (65 cm).
• Indirect Impact: If Thwaites releases the ice behind it, the resulting chain reaction could raise sea levels by an additional 10 feet (3 meters).

This potential rise is why the International Thwaites Glacier Collaboration (ITGC) has prioritized studying this specific region. The new data suggests that the shelf is more vulnerable to fracture than previously believed, even if the flat melting rates are stable.

Tidal Pumping: A New Area of Concern

Beyond the Icefin data, researchers using satellite radar interferometry have identified another process accelerating the glacier’s retreat: “tidal pumping.”

This phenomenon occurs due to the rise and fall of ocean tides. When high tide comes in, it lifts the floating portion of the glacier. This temporary lift allows warm seawater to rush underneath the ice, traveling miles inland beyond the grounding line. When the tide retreats, the water is pumped back out, but the heat remains, melting the ice from below.

Recent analysis of satellite data suggests this water intrusion is happening across a zone much wider than scientists originally estimated. The warm water is penetrating up to 3.7 miles (6 km) beneath the grounded ice. This cyclical pressure fatigues the ice, making it more brittle and susceptible to the fracturing that Icefin observed.

Why Current Models Were Wrong

For years, climate models estimated melting rates based on the temperature of the water and the friction against the flat underside of the ice shelf. These models assumed a relatively uniform melting process. The Icefin expedition proved that the texture of the ice matters immensely.

The “staircase” formations on the underside of the glacier allow for rapid melting even if the surrounding water isn’t drastically warmer. This means that small increases in ocean temperature can have disproportionately large effects on the glacier’s stability if that water finds its way into crevasses.

Peter Davis, a physical oceanographer with the British Antarctic Survey, noted that the glacier is still in trouble despite the slower melting in flat areas. The research indicates that it does not take a massive heat wave to destabilize the shelf; it only takes targeted melting in the structural weak points to trigger a retreat.

Implications for Coastal Communities

The accelerated melting of Thwaites is not an abstract scientific problem; it presents a tangible risk to coastal infrastructure worldwide. Sea level rise is already causing increased flooding in cities like Miami, New York, and Jakarta.

If the Thwaites grounding line retreats further, the flow of ice from the land into the sea will accelerate. This adds volume to the ocean, raising levels permanently. The revised understanding of crevasse melting and tidal pumping suggests that the timeline for this collapse could be shorter than the centuries-long process some earlier models predicted. While a total collapse is not expected to happen overnight, the “shelf life” of the glacier is likely shorter than we hoped.

Frequently Asked Questions

What is the “Doomsday Glacier”? It is the nickname for the Thwaites Glacier in West Antarctica. It earned this name because its collapse could trigger a significant rise in global sea levels and destabilize the surrounding West Antarctic Ice Sheet.

How much will sea levels rise if Thwaites melts? If Thwaites collapses entirely, it would contribute about 2 feet (65 cm) to global sea levels. However, if it destabilizes the surrounding glaciers, the total rise could be upwards of 10 feet (3 meters).

What did the robot Icefin find? Icefin discovered that while melting on the flat underside of the glacier is slower than expected, warm water is funneling into cracks and crevasses. This is causing rapid, localized melting that weakens the glacier’s structure significantly.

Is the glacier collapsing right now? The glacier is retreating and losing ice, contributing about 4% to current global sea-level rise. While it hasn’t fully collapsed, the grounding line is retreating rapidly, and the structural weaknesses identified by Icefin suggest the process is accelerating.

Why is warm water getting under the glacier? Ocean currents are shifting due to climate change, bringing warmer Circumpolar Deep Water closer to the Antarctic coast. Additionally, tidal pumping forces this warm water miles underneath the ice during high tides.