Greenland’s Unexpected Future: Sea Levels to Fall as Land Rises
While much of the world braces for rising sea levels due to climate change, a surprising trend is emerging in Greenland. The island is projected to experience a fall in relative sea level in the coming decades, potentially gaining significant landmass by the finish of the 21st century. This phenomenon is driven by a complex interplay of glacial isostatic adjustment and gravitational effects as the massive ice sheet shrinks.
The Rebound Effect: Land Rising After Millennia
Approximately 80 percent of Greenland is covered by glacial ice, some nearly a mile thick. For thousands of years, the weight of this ice has pressed down on the land. As global warming causes the ice sheet to lose around 200 billion tons of ice annually 1, that pressure is lessening, allowing the land to slowly rise. This process, known as glacial isostatic adjustment, is happening faster than previously expected 1.
Gravity’s Role: A Shifting Pull
The reduction in ice mass too affects gravity. The immense weight of the Greenland Ice Sheet created a gravitational pull that drew the sea surface towards the island. As the ice shrinks, this pull weakens, causing the water to move away, further contributing to the drop in relative sea level 2.
Projected Sea Level Changes
Research led by geophysicist Lauren Lewright at Columbia University, combining real-world measurements with computer modeling, predicts the extent of these changes. Under low greenhouse gas emission scenarios (RCP 2.6), Greenland is projected to gain approximately 0.9 meters (almost 3 feet) of exposed land by the end of the 21st century 2. Even under high emission scenarios (RCP 8.5), the landmass could rise by as much as 2.5 meters (over 8 feet) 2. A study published in Nature Communications confirms that local sea level will fall around the island by 2100 3.
Implications for Greenland
This localized sea level fall has significant implications for Greenlandic communities. The changes could impact coastal infrastructure, food security, and the dynamics of marine-terminating glaciers 3.
The Researcher
Lauren Lewright, a PhD student at Columbia University, is a key researcher in this area, studying the interactions between ice sheets, the solid Earth, and sea level changes over various timescales 4. Her operate, alongside that of her advisor Jacky Austermann, is providing crucial insights into these complex processes.
Global Context
It’s important to note that while Greenland experiences falling sea levels, this is a localized effect. Globally, sea levels are still rising due to thermal expansion of water and melting ice from other regions. The situation in Greenland highlights the complex and regionally variable impacts of climate change.