Greenland’s Glaciers Retreat Twice as Fast in 21st Century

A recent study reveals that the rate of glacier retreat in Greenland has more than doubled in the 21st century compared to the previous century. Conducted by researchers from Northwestern University and the University of Copenhagen, this comprehensive analysis spans from 1890 to 2022, utilizing satellite images alongside historical aerial photographs to present an unprecedented view of Greenland’s peripheral glaciers.

The research indicates that Greenland’s thousands of peripheral glaciers have entered a significant phase of accelerated retreat. By examining more than 1,000 glaciers along the country’s coastline, the study documents a striking increase in the pace of retreat, which is occurring at a rate twice as fast as it did during the 20th century.

Understanding the Data

This collaboration between Danish and American scientists employed a combination of satellite imagery and rediscovered archival photographs. The historical photos, found in the Danish National Archives, allowed researchers to trace the evolution of these glaciers over a span of 130 years. Although glacier retreat in Greenland has been documented throughout the last century, the acceleration observed in the past 20 years is alarming.

The findings align with the broader understanding of climate change, showing that Greenland’s glaciers are particularly responsive to rising temperatures. While previous research has focused primarily on the Greenland Ice Sheet, which constitutes about 80% of the island, this study shines a spotlight on the smaller, often overlooked peripheral glaciers.

Before the advent of Earth-observing satellites in the 1970s, a comprehensive understanding of how temperature fluctuations impacted these glaciers was lacking. The breakthrough came when aerial photographs, taken from open-cockpit planes in the early 20th century, were reexamined, providing critical data to evaluate historical glacier extents.

Mapping the Changes

The researchers meticulously digitized thousands of photographs and utilized geo-referencing techniques to accurately position the images. They identified terminal moraines—sedimentary ridges formed by glaciers—as indicators of previous glacier sizes before the 1930s. By comparing this historical data with more recent satellite images, the team was able to calculate the extent of glacier retreat.

Their findings show that glaciers in southern Greenland have lost an average of 18% of their length over the past 20 years, while glaciers in other regions experienced losses ranging from 5% to 10%. This rapid decline raises concerns about the potential impacts on global sea levels and freshwater sources as climate change continues to escalate.

The study, titled “Greenland-wide accelerated retreat of peripheral glaciers in the twenty-first century,” was published in the journal Nature Climate Change. The implications of this research underscore the urgent need for global efforts to mitigate climate change and its effects on vulnerable ecosystems like Greenland’s glaciers.

As temperatures continue to rise, understanding the dynamics of these melting glaciers becomes increasingly critical for anticipating future environmental changes. The work of these researchers not only contributes to the scientific community’s knowledge but also emphasizes the pressing importance of addressing climate-related challenges on a global scale.