At the top of the world, northern Greenland\u2019s huge glaciers \u2014 long thought to be relatively stable \u2014 are in trouble, a new study shows. <\/p>\n
As the ocean warms, Greenland\u2019s last remaining ice shelves are rapidly weakening, destabilizing the nearby glaciers and threatening potentially \u201cdramatic\u201d consequences for sea level rise, according to the study published Tuesday in Nature Communications. <\/p>\n
Ice shelves are tongues of floating ice that jut out over the ocean and act as dams that hold back glaciers on land and slow ice loss. When they melt and weaken, more of the land-based ice is able to slide into the ocean, adding to sea level rise. <\/p>\n
Scientists analyzed eight ice shelves buttressing glaciers in northern Greenland, which together hold enough ice to raise sea levels by 2.1 meters \u2014 nearly 7 feet \u2014 <\/strong>should they break down and melt completely. <\/p>\n While glaciers in other parts of Greenland started to lose mass in the 1980s and 1990s, he said, so far, those in northern Greenland \u201chave remained relatively stable.\u201d <\/p>\n But this appears to no longer be the case, according to the study. <\/p>\n Millan and his co-authors used thousands of satellite images, along with climate models and measurements from the field, to better understand the drivers for \u2014 and timing of \u2014\u00a0historical and current changes to the ice shelves. <\/p>\n They found a \u201csubstantial and widespread\u201d increase in ice shelf losses. Since 1978, the ice shelves supporting northern Greenland\u2019s glaciers have lost more than 35% of their total volume, according to the study. It found that since the early 2000s, three have collapsed completely, and the remaining five are melting and destabilizing nearby glaciers. <\/p>\n \u201cWe can see that the ice shelves are weakening,\u201d Millan said, \u201cand that\u2019s new key information that we didn\u2019t know, because we thought that this part of Greenland was really stable.\u201d <\/p>\n The ice loss came from a mixture of\u00a0factors, the study found, including increased calving \u2014 chunks of ice breaking off to form icebergs \u2014\u00a0and surface melting. <\/p>\n But the predominant driver was basal melting, where warm ocean currents melt the ice from beneath. Between 2000 and 2020, a \u201cwidespread increase\u201d in the rate of basal melting closely followed a rise in ocean temperature, the study found. <\/p>\n The scientists noted a direct impact on glaciers. As the ice shelves melt, the \u201cgrounding lines\u201d \u2014 the point at which the glacier stops touching the ground and starts to float \u2014 are retreating, the study found. <\/p>\n \u201cThese natural boundaries are really the key parameter that indicates the glacier stability,\u201d Millan said. As the grounding line retreats, he added, \u201cthe ice discharge into the ocean also starts to increase.\u201d <\/p>\n If the oceans continue to warm, it could permanently weaken the ice shelves, Millan said. \u201cAnd in a certain timescale, they could even collapse, which could have significant consequences on the contribution of the Greenland ice sheet to sea level rise.\u201d <\/p>\n The region already plays a large role. Between 2006 and 2018, the melting of Greenland\u2019s ice sheet contributed to more than 17% of observed sea level rise, according to the report. <\/p>\n It is not possible to give timescales for when such a collapse could happen, Millan said, but changes have happened fast since the early 2000s. <\/p>\n After the collapse of the Zachari\u00e6 Isstr\u00f8m glacier\u2019s ice shelf in 2003, the ice discharge into the ocean doubled, according to the study. Millan said when he visited the glacier in 2016 and 2017, the changes were alarming. He described it as \u201ca chaos of tabular icebergs.\u201d <\/p>\n The future of the glaciers will depend heavily on what the world does to reduce planet-heating pollution, Millan said. <\/p>\n The report calls for continued monitoring to better asses how the ice shelves will respond to climate change and, in particular, to build on the study\u2019s findings about the complex process of basal melting and the potential impacts on sea level rise. <\/p>\n \u201cThis will ultimately provide insight into the future of these glaciers as well as the fate of larger ice shelves in Antarctica,\u201d the report notes. A recent study in Antarctica found that the rapid melting of the continent\u2019s ice shelves may now be \u201cunavoidable\u201d due to melting from below. <\/p>\n Sophie Nowicki, an ice sheet expert in the geology department at the University at Buffalo, who was not involved in the research, said the study\u2019s findings are significant because of the insight they provide into sources and triggers of changes to Greenland\u2019s ice sheet. <\/p>\n The study also adds to an overall understanding of how polar regions are responding to the human-induced climate crisis, Nowicki said. <\/p>\n The poles were once seen as \u201cfairly boring,\u201d she said, but since scientists began to observe them with satellites around four decades ago, it has become clear that \u201cthese are dynamic, very fragile regions.\u201d <\/p>\n As the planet continues to heat up, she added, \u201cwe should be concerned by how fast the changes are happening, but we should not be surprised.\u201d <\/p>\n\n At the top of the world, northern Greenland\u2019s huge glaciers \u2014 long thought to be relatively stable \u2014 are in trouble, a new study shows. As the ocean warms, Greenland\u2019s last remaining ice shelves are rapidly weakening, destabilizing the nearby glaciers and threatening potentially \u201cdramatic\u201d consequences for sea level rise, according to the study published <\/p>\n","protected":false},"author":0,"featured_media":11296,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[23],"tags":[],"class_list":{"0":"post-11295","1":"post","2":"type-post","3":"status-publish","4":"format-standard","5":"has-post-thumbnail","7":"category-world"},"_links":{"self":[{"href":"https:\/\/shareperformanceinsight.com\/index.php\/wp-json\/wp\/v2\/posts\/11295","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/shareperformanceinsight.com\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/shareperformanceinsight.com\/index.php\/wp-json\/wp\/v2\/types\/post"}],"replies":[{"embeddable":true,"href":"https:\/\/shareperformanceinsight.com\/index.php\/wp-json\/wp\/v2\/comments?post=11295"}],"version-history":[{"count":0,"href":"https:\/\/shareperformanceinsight.com\/index.php\/wp-json\/wp\/v2\/posts\/11295\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/shareperformanceinsight.com\/index.php\/wp-json\/wp\/v2\/media\/11296"}],"wp:attachment":[{"href":"https:\/\/shareperformanceinsight.com\/index.php\/wp-json\/wp\/v2\/media?parent=11295"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/shareperformanceinsight.com\/index.php\/wp-json\/wp\/v2\/categories?post=11295"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/shareperformanceinsight.com\/index.php\/wp-json\/wp\/v2\/tags?post=11295"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}