Credit: CC0 Public Domain
A new study reveals that the melting of the Juneau Icefield, one of North America’s largest icefields, is rapidly accelerating and could soon reach a point of no return. This research, conducted by a team of scientists, sheds light on the alarming situation unfolding near the Alaskan capital of Juneau, where the icefield spans the Alaska-Canada border.
During the summer of 2022, I embarked on a skiing expedition across the vast expanse of the icefield, alongside fellow researchers, tracing the tracks left by those who came before us under the scorching sun. The icefield is home to around 40 massive glaciers that flow towards the sea, along with numerous smaller glaciers adorning the surrounding mountain peaks.
Our findings, recently published in Nature Communications, demonstrate how Juneau exemplifies a climate feedback loop in action: as temperatures rise, the amount of snow remaining through the summer diminishes, leading to increased exposure of ice to sunlight and higher temperatures, resulting in accelerated melting.
Many of Alaska’s glaciers, including those in Juneau, are characterized by a top-heavy structure, with substantial ice and snow at higher elevations above the end-of-summer snowline. However, as this snowline creeps higher, more of the glacier’s mass becomes vulnerable to melting, causing a rapid thinning of the icefield and lowering of the plateau.
This continuous cycle of melting has caused the glaciers to retreat at an unprecedented rate, with the icefield progressively losing thickness. Once a critical threshold is crossed, these feedback mechanisms can intensify the melting process, leading to a self-sustaining loss of snow and ice, regardless of future climate conditions.
By utilizing satellite data, photographs, and historical records, we were able to track the ice loss across the Juneau Icefield from the end of the “Little Ice Age” to the present day. Our analysis revealed a consistent decline in glacier size since the late 18th century, with a significant acceleration in melting rates observed since the late 20th century. The glaciers in the region have been shrinking at an alarming pace, highlighting the urgent need for action to address the impacts of climate change on these vital ecosystems.
2024-07-06 19:15:03
Post from phys.org
