Ice Sheets

Ice Sheets: The Drivers of Climate

Ice sheets, massive bodies of ice covering vast regions, play a crucial role in shaping Earth’s climate. Their dynamics can trigger dramatic shifts in temperature and weather patterns.

One such example is the Heinrich events, periods of rapid climate change marked by the discharge of icebergs into the North Atlantic. These events, which occurred every 7,000 to 12,000 years, were caused by the buildup and collapse of the ice sheet covering North America.

As snow accumulated on the ice sheet, its weight compressed the underlying rocks, creating a slippery paste. When this paste reached a critical thickness, it would flow rapidly down Hudson Strait, carrying rocks and debris into the ocean. The release of this ice and meltwater altered ocean currents and wind patterns, leading to significant climate shifts.

Ice Sheets and Flickers

Recent research has also revealed a series of shorter cold snaps, known as “flickers,” which occur between Heinrich events. These flickers are caused by the buildup and discharge of ice from the St. Lawrence Valley ice sheet.

Like the Heinrich events, flickers involve a rapid buildup of ice followed by a sudden discharge. However, the St. Lawrence ice sheet is smaller and receives more snowfall, so flickers occur more frequently than Heinrich events.

The Interplay of Ice and Climate

Initially, scientists believed that climate change was solely driven by the dynamics of ice sheets. However, new data has shown that the relationship between ice sheets and climate is more complex.

While ice sheet discharge can trigger climate change, climate change can also influence ice sheet dynamics. For example, warmer temperatures can create floating ice shelves that prevent glaciers from discharging.

Ongoing Scientific Exploration

Scientists continue to explore the intricate relationship between ice sheets and climate. They are investigating the role of floating ice shelves, the impact of multiple ice sheets, and the use of oxygen isotopes to date ice cores.

This ongoing research is essential for understanding the past, present, and future of Earth’s climate. By unraveling the complexities of ice sheet dynamics, scientists can better predict and mitigate the effects of climate change.

Past Global Flood Reveals Antarctica’s Ice Sheet Vulnerability

The Eemian Mystery

Between 116,000 and 129,000 years ago, sea levels were significantly higher than today, submerging coastal areas and entire islands. The cause of this rise during the Eemian period has been a mystery, but new research suggests it was triggered by the collapse of the West Antarctic Ice Sheet.

Greenland Exonerated

Scientists initially believed that the Greenland Ice Sheet was responsible for the sea level rise during the Eemian. However, recent geological evidence indicates that Greenland’s ice remained intact, clearing it of blame.

West Antarctica’s Role

The West Antarctic Ice Sheet became the prime suspect due to its massive size and instability. To investigate its role, glaciologists analyzed sediment cores drilled off the coast of the ice sheet. They found that during the Eemian, material from the Amundsen province and Pine Island Glacier areas gradually disappeared, leaving only silt from the Antarctic Peninsula.

Ice Sheet Collapse

This finding suggests that the ice in Amundsen and Pine Island Glacier areas ceased flowing or melted, while the glaciers in the Antarctic Peninsula persisted. The researchers concluded that the West Antarctic Ice Sheet had collapsed, eroding its ability to contribute sediment to the marine environment.

Temperature Sensitivity

The collapse of the West Antarctic Ice Sheet highlights its vulnerability to temperature changes. This raised concerns because the ice sheet is currently showing signs of stress. However, it’s important to note that the Eemian period is not an exact parallel to today’s climate change, as it was driven by natural factors rather than human activities.

Signs of Instability

Despite the differences between the Eemian and present-day climate, Antarctica is exhibiting signs of instability. The West Antarctic Ice Sheet has lost three trillion tons of ice since 1992, with ice losses accelerating in recent decades.

East Antarctica’s Concerns

Not just the West, but also the East Antarctic Ice Sheet, long considered stable, is showing signs of ice loss. Glaciologists have observed thinning and accelerating flow rates of glaciers in Vincennes Bay and the massive Totten Glacier. These systems hold enough ice to raise sea level by 30 feet.

Impact on Sea Level

According to NASA, Antarctic ice melting has already contributed to a 0.3-inch increase in global sea levels since 1992. If all of Antarctica’s ice melted, sea level would rise by an immense 190 feet. While this may seem extreme, studies suggest that burning all available fossil fuels could potentially melt the entire ice cap.

Further Research

Researchers are planning to drill additional sediment cores off Antarctica to gain more insights into the Eemian period. Their findings will help refine our understanding of the vulnerability of Antarctic ice sheets to climate change and its potential consequences for sea level rise.

Ice Sheets: The Unsung Drivers of Climate’s Rhythmic Dance

Ice Sheets and the Dance of Climate Change