People have less time: Greenland's icy shield is literally breaking apart.

Cracks on the surface of glaciers, formed by stress, are a vivid testament to the vulnerable state of the planet's ice sheets. The direction and size of these cracks indicate how the ice sheet is flowing toward the ocean: they can be tiny, just a few millimeters wide, or they can sometimes reach meters in width, as reported by IFLScience.

Occasionally, these cracks on the glacier's surface may be covered by deceptive snow bridges, which require appropriate protective gear and rescue training to traverse. The cracks can appear particularly frightening where ice meets the ocean—scientists note that in such areas, their width can reach a monstrous 100 meters. Researchers have now discovered that these cracks are growing and expanding across Greenland.

Researchers are not particularly surprised that cracks throughout Greenland are becoming larger: as the ocean warms, the ice sheet accelerates in response, increasing the stresses acting on its surface. Unfortunately, satellite observations and fieldwork are so sparse that today scientists have little idea of how widespread and rapid this process is.

In a new study, scientists mapped the cracks across the Greenland ice sheet in 2016 and 2021. To do this, the team used three-dimensional maps of polar regions based on high-resolution satellite imagery. By applying image processing techniques to over 8,000 maps, the researchers were able to estimate how much water, snow, and air would be needed to "fill" each crack across the Greenland ice sheet. As a result, they were able to calculate the depth and volume and examine how these cracks have developed.

The results indicate that from 2016 to 2021, there was a significant increase in the volume of cracks in the rapidly flowing sectors of the Greenland ice sheet. In the southeast of the ice sheet, an area that has been particularly vulnerable to acceleration and retreat caused by the ocean in recent years, the volume of cracks increased by more than 25%.

At the same time, scientists found that the volume of cracks across the entire ice sheet increased by only 4.3%, which surprised the team. Such results were closer to balance than to the extremes observed in certain sectors. The team continued their investigation and discovered that the significant growth in some areas was actually offset by one source: a draining glacier known as Sermeq Kujalleq.

It is worth noting that Sermeq Kujalleq is the fastest-flowing glacier on the planet. Studies show that its speed is nearly 50 meters per day, contributing significantly to Greenland's overall contribution to rising sea levels. Observations also revealed that in 2016, the glacier responded to the influx of cold water from the northern Atlantic Ocean, resulting in a slowdown in its flow and a thickening of the glacier itself. As this occurred, the cracks on the surface began to close, offsetting the growth elsewhere on the ice sheet. Unfortunately, this slowdown did not last long, and by 2018, the glacier returned to its accelerating state.

The authors of the study note that cracks in glaciers play a crucial role in their lifecycle: as the cracks grow, the potential for ice sheet acceleration increases. Cracks also channel surface meltwater to the heart of the ice sheet: once inside, the water can warm the ice and lubricate the bed over which the glacier slides. Unfortunately, both of these factors contribute to the loss of the ice sheet.