Since North Greenland’s glaciers contain enough ice to raise the sea level by roughly seven feet, scientists have long believed that they have been stable. However, a recent study that was released on Tuesday discovered that the region’s ice shelves had lost more than a third of their volume over the past 50 years due to rising temperatures; if this trend persists, experts warn that there might be “dramatic consequences” for the planet’s glaciers.
The study, which was published in Nature Communications, discovered that North Greenland’s ice shelves “have lost more than 35% of their total volume” since 1978. It did this by using hundreds of satellite photos and climate modeling.
The portion of ice sheets, a type of glacier, that floats over water is known as an ice shelf. Researchers said that of the five main shelves that remain, they have observed a “widespread increase” in the amount of material they have lost, primarily as a result of ocean warming. Three of those shelves in North Greenland have “completely” collapsed, they claimed.
Between 2000 and 2013, the size of one of the shelves, named Steenbsy, decreased to just 34% of its former size. Scientists reported that since 1978, the area of floating ice has shrunk by more than a third of its original extent, in addition to the total loss of ice shelf volume.
Given that the second-largest contributor to sea level rise is the Greenland ice sheet, this observation could be quite problematic. Scientists found that between 2006 and 2018, the single sheet was accountable for over 17% of the rise in sea level during that time.
“The observed increase in melting coincides with a distinct rise in ocean potential temperature, suggesting a strong oceanic control on ice shelves changes,” the researchers stated. “…We are able to identify a widespread ongoing phase of weakening for the last remaining ice shelves of this sector.”
The melting of ice below the surface, or basal melting, may also “be playing a complex and crucial role in thinning the ice shelf from below,” according to the study’s authors. Furthermore, when the ice gets too thin, the building is more “prone to enhanced fracturing.”
“This makes them extremely vulnerable to unstable retreat and ice shelf collapse if ocean thermal forcing continues to rise, which is likely to be the case in the coming century,” they said. They added that the ensuing discharge “could have dramatic consequences in terms of sea level rise.”
When global temperatures rise, glaciers and ice sheets melt more quickly than they can replenish themselves with snow and ice. This is especially true in the oceans, which absorb 90% of the planet’s warming. The melting of ice is accelerated by rising ocean temperatures and air temperatures.
The World Meteorological Organisation predicted earlier this year that at least one of the following five years will be the hottest year ever recorded, pushing Earth’s warming over 1.5 degrees Celsius over pre-industrial levels. The hottest three months on record for Earth occurred this summer, according to a September analysis from the European Union’s Copernicus Climate Change Service.
