"Our findings shed new light on one area of uncertainty, suggesting climate variability has a significant impact on melting ice sheets and sea level rise.". Even in frigid Antarctica, summer warmth can turn ice into water. Fluctuations in the weather can have a significant impact on melting Antarctic ice, and models that do not include this factor can underestimate the global impact of sea level rise, according to Penn State scientists. The paper says ocean temperatures during the last interglacial were likely up to 2C warmer than they are today and global sea levels were 6-9 metres higher. May 28, 2020 May 28, 2020 A new study in the journal Science found that floating ice shelves can melt much more rapidly than previously thought—at a rate of about six miles per year. "Ice melt projections may underestimate Antarctic contribution to sea level rise." The loss of the Thwaites glacier could trigger the broader collapse of the West Antarctic ice sheet. Questions? 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Rex Had Huge Growth Spurts, but Other Dinos Grew Slow and Steady, Geoscientists Discover Ancestral Puebloans Survived from Ice Melt in New Mexico Lava Tubes. Blue ice areas are created by katabatic winds. Antarctic sea ice extent likely reached its annual minimum on February 20 and 21, 2020. Anomalous high temperatures were recorded across Antarctica throughout the summer of 2019/2020, leading to melting of ice and exposure of new ice‐free areas. ScienceDaily shares links with sites in the. Materials provided by Penn State. Scientists have been more concerned about West Antarctica, where the ice has been melting faster in recent years, Rignot said. Fluctuations in the weather can have a significant impact on melting Antarctic ice, and models that do not include this factor can underestimate … However, that process smooths out peaks caused by climate variability and reduces the average number of days above temperature thresholds that can impact the ice sheet melt, creating a bias in the results, the scientists said. “It means that a large part of the west Antarctic almost certainly disappeared in the last interglacial. Citation: Satellite record gives unprecedented view of Antarctic ice shelf melt pattern over 25 years (2020, August 13) retrieved 25 November To study the effects of internal climate variability, the researchers analyzed two large ensembles of climate simulations. The Antarctic ice sheet is a complex system, and modeling how it will evolve under future climate conditions requires thousands of simulations and large amounts of computing power. "That increase alone is comparable to the amount of sea level rise we have seen over the last few decades," said Forest, who has appointments in the departments of meteorology and atmospheric science and geosciences. In February 2020, along with record-breaking high temperatures in the region, satellite images showed that the surface of the largest remaining ice shelf on the Antarctic Peninsula was experiencing a lot of melt. Antarctica logs hottest temperature on record with a reading of 18.3C. Ice melt projections may underestimate Antarctic contribution to sea level rise Date: October 9, 2020 Source: Penn State Summary: Citation: Shift in atmospheric rivers could affect Antarctic sea ice, glaciers (2020, November 23) retrieved 29 November 2020 from This document is subject to copyright. We now assess parameterized melt rate patterns for the entire Antarctic ice sheet in comparison to the observational melt patterns from Rignot et al. "Every bit adds on to the storm surge, which we expect to see during hurricanes and other severe weather events, and the results can be devastating.". Additionally, for years, the IPCC reports have been looking at sea level rise without considering this additional variability and have been underestimating what the impact may be," Forest said. “As you walk towards the mountain, you walk over increasingly older ice,” Turney said. Using archived Extensive parts of the ice sheet are in contact with ocean water, and previous studies have suggested that warming oceans could cause large chunks to break away. The team, led by scientists at the University of NSW, examined the cause of high sea levels during a period known as the last interglacial, which occurred 129,000-116,000 years ago. Original written by Matthew Carroll. He said the West Antarctic was particularly vulnerable to ocean warming because it sits mostly on the sea bed, rather than on land. Compared to the Arctic, Antarctic sea ice shows less variability in summer, and more variability in winter. When these winds blow over mountains, they remove snow and ice, allowing ancient ice to come to the surface. But our findings suggest the West Antarctic Ice Sheet may be close to a tipping point. Penn State. 7 b). He said the research also suggested this mass melting happened quite early during the ocean warming “somewhere between zero and 2C”. Accounting for climate variability caused models to predict an additional 2.7 to 4.3 inches -- 7 to 11 centimeters -- of sea level rise by 2100, the scientists recently reported in the journal Climate Dynamics. It is not intended to provide medical or other professional advice. "If we're just running with average conditions, we're not seeing these extremes happening on yearly or decadal timescales.". Financial support for ScienceDaily comes from advertisements and referral programs, where indicated. The study’s lead author Chris Turney is a climate change and earth scientist at UNSW. Their study finds that melting of the West Antarctic ice sheet caused a sea-level rise of more than three metres and it took less than 2C of ocean warming for that to occur. The general picture is that nonlocal MeanAnt produces relatively uniform melt rates within individual sectors, with maximum present-day melt rates below 25 m yr −1 (Fig. It flowed rapidly into the ocean,” he said. “Ocean-driven melting at the base of ice shelves is already the main contributor to mass loss from the Antarctic ice sheet,” he said. "We know ice sheets are melting as global temperatures increase, but uncertainties remain about how much and how fast that will happen," said Chris Forest, professor of climate dynamics at Penn State. The authors say their findings could have “major implications” for the future given the ocean warming and ice melt currently occurring in Antarctica. Climate Change May 4, 2020 - by Tim Lydon ScienceDaily, 9 October 2020. 585, September 24, 2020, p. 538. doi: 10.1038/s41586-020-2727-5. That melt is equivalent to about 120,000 square miles of 1-meter thick ice. Large ensembles are generated by starting each member with slightly different initial conditions. They used some shallow drilling to take ice samples from the surface. (a) Monthly mean anomaly (the difference from climatological monthly mean) of 2 m air temperature from NCEP/NCAR Reanalysis 1 data (Kalnay et al., 1996 ) for November 2019 to February 2020. AGU Blogosphere: From a Glacier’s Perspective (2020, February 19) Boydell Glacier Accumulation Zone Rapid Melt Feature Development February 2020. “So the question is how much could fall into the ocean and this is where the last interglacial [period] is so important.”. Antarctica: Too Big to Melt A summer of extremes leaves sobering questions about the state of Earth’s largest store of ice, capable of inundating coastlines worldwide as it melts. “A reduction in the buttressing effect of ice shelves is a negative feedback that can lead to glacial acceleration and a … The process may expose ice cliffs so tall that they collapse under their own weight, inducing a domino effect that further depletes the ice shelf. While it is understood that continued warming may cause rapid ice loss, models that predict how Antarctica will respond to climate change have not included the potential impacts of internal climate variability, like yearly and decadal fluctuations in the climate, the team of scientists said. www.sciencedaily.com/releases/2020/10/201009102731.htm (accessed December 2, 2020). Professor of Science in the Department of Earth and Planetary Sciences. They found atmospheric variations had a larger and more immediate impact on the ice sheet, but ocean variability was also a significant factor. Note: Content may be edited for style and length. Vol. “What these results suggest, or show, is that when people talk about a 2C warmer world as a good thing, actually what it shows is we don’t want to get close to 2C,” he said. Countries have signed on to the Paris agreement which aims to keep global heating below 2C. The record in recent decades for the highest level of ice to melt in Antarctica in one day was reached on Christmas Eve, data suggests. 7a. "This additional ice melt will impact the hurricane storm surges across the globe. ScienceDaily. S. Sadai et al. Have any problems using the site? Turney said this gap coincided with an extreme rise in sea level and suggested a period in which there was no ice accumulating in that valley. "Ice melt projections may underestimate Antarctic contribution to sea level rise." At the peak of the 2019-2020 melt season, jewel-toned ponds of meltwater spanned a vast area on the George VI ice shelf—a huge slab of floating glacier ice attached to the western side of the Antarctic Peninsula. Melting of the Antarctic ice sheet will cause sea level rises of about two and a half metres around the world, even if the goals of the Paris agreement are met, research has shown. THIS POST IS A CRITICAL REVIEW OF A PHYS.ORG ARTICLE PUBLISHED IN OCTOBER 2020 SAYING THAT GLOBAL WARMING IS DRIVING ANTARCTIC ICE MELT AND GLOBAL SEA LEVEL RISE FASTER THAT LINK TO THE PHYS.ORG ARTICLE: https://phys.org/news/2020-10-ice-underestimate-antarctic-contribution-sea.html THIS ASSEESSMENT IS CREDITED TO RESEARCH BY MATTHEW … (), as shown in Fig. Ice shelves are the gatekeepers for glaciers flowing from Antarctica toward the ocean. Because of this, modelers test how the ice will respond using a mean temperature found by averaging the results of climate models. Or view hourly updated newsfeeds in your RSS reader: Keep up to date with the latest news from ScienceDaily via social networks: Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Antarctic ice melt related to tropical weather shifts: Study by Gloria Dickie on 1 April 2020 Scientists predominantly believe that the tropics have the largest influence on global weather. AGU Blogosphere: From a Glacier’s Perspective (2020, February 17) Record Antarctic Temperatures in Feb. 2020 Impact on Eagle Island Ice Cap. Logs hottest temperature on record with a reading of 18.3C, Rignot said Antarctica throughout the summer 2019/2020. Of 2019/2020, leading to melting of ice and exposure of new ice‐free areas edited for style length... 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