Without oceans, climate change would be even worse. The ocean absorbs 90 percent of the excess heat humans pump into the atmosphere. Warming oceans are already having devastating effects on the creatures that live there, but they are hitting us in even more unexpected ways. It contributes to the destruction of Iceza. above of Greenland.
That degraded ice sheet (land-based ice sheet) was responsible for more than 17 percent of the observed sea level rise between 2006 and 2018, and new research has even more ominous news. (Greenland has much less ice than Antarctica, but it is decreasing) 270 billion tons Northern Greenland’s ice shelves (ice that float in the ocean rather than on land) have actually lost more than a third of their volume since 1978 thanks to erosion from warm ocean water. Off their bellies. Three of these northern ice shelves have completely collapsed since 2000, and the remaining five are rapidly deteriorating, resulting in destabilization of nearby glaciers.
While there is an ice shelf themselves Because they are already floating in the ocean, they do not contribute much to sea level rise and act like dams, regulating the amount of ice that is released into the ocean from within land-based ice sheets. “We can see that the ice shelf is getting weaker and weaker,” says Romain Milan, a glaciologist at the University of Grenoble-Alpes and lead author of the new paper. paper in nature communications. “In response to this increased melting, we are already seeing glaciers retreating and shedding even more ice into the ocean.”
Milan and his colleagues used satellites and modeling to check several aspects of the health of northern Greenland’s ice shelves. First, satellite images allowed us to determine how the total volume and area of ice has decreased over the decades. Even deeper, they were able to trace the “grounding line” where the ice sheet lifts off the land and forms an ice shelf. As the tide rises and falls, the ice moves up and down, and satellites track its movement to pinpoint the exact location of the grounding line.
As ice shelves are shrinking and thinning, they are rapidly retreating inland, where the topography poses even more problems. Inland from the coast, the slope of the river bed becomes retrograding, and the surface beneath the ice deepens toward the center of the island. “If the ground wire starts to retreat, it can end up in an unstoppable retreat because it’s on a retrograde bed slope,” Millan says.
On the other hand, if the slope goes down, Up As you move inland, it becomes harder for the ground wire to retreat. Imagine how far inland floodwaters would reach if the terrain was flat compared to mountainous areas. “As the grounding moves toward deeper layers, it means that the amount of ice from the layer to the surface gets thicker, which means more ice is released into the ocean,” Millan says. “As it descends, more ice is exposed to warmer oceans, which results in more ice melting, more velocity, and more release.”