Categories: world

Greenland's meltdown melts “from the charts” compared to the past four centuries – ScienceDaily

Surface melting over Greenland's milky-thick ice sheet began to rise in the mid 1800's and then dramatically ramped in the…

Surface melting over Greenland’s milky-thick ice sheet began to rise in the mid 1800’s and then dramatically ramped in the 20th and 2100s, which showed no signs of decreasing, according to recent research published December 5, 2018, in the journal Nature . The study provides new evidence of the impact of climate change on arctic melting and the global sea level.

“The melting of the green ice sheet has been in overpressure, which means that melting in Greenland is increasing more than anywhere in the last three and a half centuries, if not thousands of years,” says Luke Trusel, a glaciologist at Rowan University & # 39; s School of Earth & Environment and former PhD student at Woods Hole Oceanographic Institution and principal author of the study. “And increased melt began about the same time as we began to change the atmosphere in the mid 1

800’s.”

“From a historical perspective, today’s melting frequencies are outside the charts, and this study provides evidence to prove this” Sarah Das, a glaciologist at Woods Hole Oceanographic Institution (WHOI) and co-author of the study. “We found a fifty percent increase in the total ice pond wastewater against industry beginnings and a thirty percent increase since the 1900s alone.”

Ice loss from Greenland is one of the most important driving forces for global sea level rise. Iceberg calving in the sea from the edge of the glaciers is a component of water that once again enters the ocean and raises sea levels. But more than half of the ice water entering the ocean comes from runoff from melted snow and icecream on top of the ice. The survey suggests that if greenery melting continues with “unprecedented prices” – as scientists attributed warmer summers – it can accelerate the already rapid rise in sea level.

“Instead of increasing steadily as the climate warms, Greenland is melting more and more for every degree of warming. The melting and sea level rise we have already observed will be dwarfed by what can be expected in the future when the climate continues to warm “said Trusel.

To determine the intensity of Greenland’s ice cream has melted in recent centuries, the research group used a drill of a traffic light pole to extract ice cores from the ice and an adjacent coastal site in places over 6000 feet above sea level. The researchers drilled at these heights to ensure that the cores would contain records of prior melt intensity so that they could extend their records back to the 18th century. During hot summer days in Greenland melting takes place over much of the ice surface. At lower elevations, where melting is greatest, melting water flows from the ice and contributes to sea level rise, but no record of melt remains. However, at higher elevations, the summer fluid quickly recovers from the contact with the frozen snowpack located below. This prevents it from flying in the ice in the form of run-off. Instead, it forms clear clear bands that stack up in layers of tightly packed ice over time.

The nuclear samples were taken back to ice core laboratories at the US Core Facility at Denver, Colo., WHOI in Woods Hole, Mass., Wheaton College in Norton, Mass., And Desert Research Institute in Reno, Nev. Where the researchers measured physical and chemical properties along the nuclei to determine the thickness and age of the melting layer. Dark bands that run horizontally across the cores, like ticks on a ruler, allowed researchers to visually chronicle the strength of melting the surface from year to year. Thicker melting layers represented years of higher melting, while thinner sections indicated years with less melting.

Combining results from several ice cores with observations of melting from satellites and sophisticated climate models, researchers could show that the thickness of the annual melting layer that they observed clearly not only tracked how much melting occurred in the core areas, but also much more across Greenland. This breakthrough made it possible for the team to reconstruct meltwater treatment at the lower edges of the ice lengths – those areas that contribute to sea level rise.

Icecream registry provides a critical historical context because satellite measurements – which researchers trust today to understand melting rates in response to changing climate – have only existed since the late 1970s, “said Matt Osman, a PhD student in the MIT-WHOI Joint Program and co-author of the study.

“We have had a feeling that there has been a lot of melting in recent decades, but we previously had no reason for comparison with the melting grades that went further in time,” he says. “By sampling ice, we could expand satellite data with a factor of 10 and get a clearer picture of how extremely unusual melting has occurred in recent decades compared to the past. “

Threats said that the new research proves that the rapid melting observed in recent decades is very unusual when it is placed in an historical context.

“In order to respond to what can happen to Greenland, we will understand how Greenland has already responded to climate change,” he said. “What our ice cores show is that Greenland is now in a state where it is much more sensitive to further temperature increases than 50 years ago. “

A remarkable aspect of the results, said Das, was how little further The heating it now takes to cause large nails in ice melting.

“Even a very small temperature change caused an exponential increase in melting in recent years,” she said. “So the reaction of the ice-cream to human-induced heating has been unlinear.” Threats came to the conclusion that “heating means more today than before.”

Additional co-authors are: Matthew B. Osman, MIT / WHOI Joint Program in Oceanography; Matthew J. Evans, Wheaton College; Ben E. Smith, University of Washington; Xavier Fettweis, Leige University; Joseph R. McConnell, Desert Research Institute; and Brice PY Noël and Michiel R. van den Broeke University of Utrecht.

This research was funded by the US National Science Foundation, institutional support from Rowan University and Woods Hole Oceanographic Institution, the United States Department of Defense, the Netherlands Organization for Scientific Research, the Netherlands Earth System Science Center and the Belgian National Research Foundation.

Share
Published by
Faela