Subglacial Lakes Discovered Under Antarctic Ice

Scientists have uncovered a massive, dynamic network of liquid water hiding beneath the frozen surface of Antarctica. Far from being a solid and static block of ice, the continent sits on top of an active plumbing system. Researchers have found that these subglacial lakes frequently fill and drain, creating a slippery base that significantly accelerates how fast glaciers melt and flow into the ocean.

The Hidden Plumbing of Antarctica

For decades, scientists viewed the ice sheets of Antarctica as relatively rigid structures that slowly deformed under their own weight. We now know that the reality is much more complex. Researchers have identified over 400 subglacial lakes beneath the Antarctic ice sheet.

While some of these lakes are massive and ancient, like Lake Vostok which is roughly the size of Lake Ontario, the most concerning discoveries involve smaller, highly active water systems. These active lakes do not just sit there. They are part of a massive, interconnected plumbing network. Water constantly moves between them, flowing through subglacial rivers that stretch for hundreds of miles under thousands of feet of solid ice.

Two main factors keep this water liquid despite the freezing temperatures on the surface. First, geothermal heat radiates up from the Earth’s core, gently warming the bedrock. Second, the sheer weight of ice that is several kilometers thick creates immense pressure. High pressure actually lowers the freezing point of water. This allows liquid water to exist at temperatures hovering around minus 2 degrees Celsius.

How NASA Tracks Invisible Lakes

Finding water buried under two miles of solid ice is incredibly difficult. Researchers cannot simply look at satellite photos to find these lakes. Instead, they rely on advanced laser technology to track the movement of the ice surface itself.

NASA uses a satellite called ICESat-2 to map these hidden water systems. Launched in 2018, ICESat-2 carries a highly sensitive instrument called the Advanced Topographic Laser Altimeter System (ATLAS). This instrument fires 10,000 laser pulses per second down to the Earth and measures exactly how long it takes for the light to bounce back.

By measuring the exact height of the ice, scientists can watch the ice sheet breathe. When a subglacial lake fills with water from melting ice or connecting rivers, the immense pressure bows the solid ice sheet upward by several meters. When the lake suddenly drains, the ice surface sinks back down. Teams from institutions like the Scripps Institution of Oceanography monitor these exact elevation changes to map out where the lakes are and how much water is moving through them.

Accelerating Glacier Melt Rates

The most critical part of this discovery is how these water systems impact glacier movement. Glaciers act like slow-moving rivers of ice that carry frozen water from the center of Antarctica out to the ocean. When subglacial lakes drain, they release massive floods of water that spread out between the bedrock and the bottom of the glacier.

This process is known as basal lubrication. You can think of it like a car hydroplaning on a wet road. The sudden rush of water drastically reduces the friction holding the glacier in place. Once the glacier loses its grip on the rough bedrock, it slides much faster toward the sea.

This is especially dangerous in West Antarctica. Researchers are closely monitoring the Thwaites Glacier and the Pine Island Glacier. The Thwaites Glacier, often referred to as the Doomsday Glacier, is roughly the size of Florida. It is currently losing about 50 billion tons of ice every year. When subglacial lakes beneath these glaciers drain, they push the ice out into the warmer ocean waters at a much faster rate. Once the ice reaches the ocean, the relatively warm saltwater melts it rapidly from below.

The Impact on Global Sea Levels

Understanding these subglacial lakes is crucial for predicting our future climate. Every time ice slides off the land and into the water, global sea levels rise.

Currently, Antarctica contributes about 1 millimeter to global sea level rise each year. However, if massive systems like the Thwaites Glacier speed up too much and collapse, the results would be catastrophic. The total collapse of the Thwaites Glacier alone could raise global sea levels by 65 centimeters (roughly two feet).

Older climate models did not account for these active water systems. They assumed glaciers moved at a steady, predictable pace based entirely on air temperatures and ice thickness. Now, scientists are rushing to update their models. Knowing exactly when and where these subglacial lakes will drain allows researchers to calculate the exact speed at which these massive ice streams will march toward the ocean.

Frequently Asked Questions

What is a subglacial lake? A subglacial lake is a body of liquid water located underneath a glacier or an ice sheet. They form where geothermal heat from the Earth and intense pressure from the ice above cause the bottom layer of ice to melt.

How does water stay liquid under a freezing ice sheet? The sheer weight of miles of ice creates enormous pressure. High pressure lowers the freezing point of water, allowing it to remain liquid even when the temperature drops below zero degrees Celsius. Geothermal heat from the bedrock also contributes to keeping the water from freezing.

Why are researchers so worried about the Thwaites Glacier? The Thwaites Glacier holds enough ice to significantly raise global sea levels if it melts. It is currently acting as a plug that holds back the rest of the West Antarctic Ice Sheet. If basal sliding causes it to slip into the ocean faster, it could trigger a massive acceleration in global sea level rise.