The Greenland ice melt began in the middle of the 19th century. Picture about Pixabay.
The Greenland ice sheet is currently melting "outside the tables" compared to the last 350 years, warned a new study by scientists from the Woods Hole Oceanographic Institution (WHOI).
According to researchers, Greenland's meltdown began in the mid-19th century and today contributes more than ever to sea level in the past three centuries. The results also clearly show the effects of climate change on the melting of the Arctic and global sea-level rise, according to the research team.
"From a historical perspective, today's melt rates are outside the tables, and this study provides the evidence," Dr. Sarah Das, glaciologist at WHOI and co-author of the study.
"We've found that the meltwater runoff of the ice sheet has risen by 50% compared to the beginning of the industrial era, and that has been 30% since the early 20th century alone."
To determine the speed of Greenland ice melting in the past centuries, the team used a long drill to extract ice cores from the ice sheet in Greenland and an adjacent coastal ice cap. The ice core samples were collected at sites over 1,830 meters high, allowing them to trace their records back to the 17th century.
At higher altitudes, summer meltwater does not run off the ice, but solidifies after coming in contact with the underlying snowpack. This frozen meltwater forms pronounced ice bands, which accumulate over the years to densely packed ice sheets.
The core samples collected by the researchers were sent to the ice core laboratories in the USA, where scientists determined the age and thickness of the enamel layers. Melt layers that were thicker indicated the years in which more melts occurred, while thinner sections represented years with lower melt levels.
The team analyzed these results in combination with imaging data collected from different satellites and data from sophisticated climate models, which allowed the melting of ice to be determined not only at the core site but throughout Greenland.
The results indicate that the rapid melting of the ice surface in Greenland over recent decades has been remarkable in the historical context, and that the region today is much more sensitive to warming than it was a few decades ago. Well, even a very small temperature change in the region can lead to massive melting peaks, according to the study.
The results of the study will be published in a journal nature,