One of the biggest icebergs ever recorded has "finally" broken away from the Larsen C ice shelf in Antarctica, researchers studying the event announced.
The iceberg, which will likely be dubbed A68, weighs more than a trillion tonnes, has a volume twice that of Lake Erie, and is about 5,800 square kilometers in size—roughly the size of Delaware.
<p><span></span>According to <a href="http://www.projectmidas.org/" target="_blank">Project MIDAS</a>, the UK-based Antarctic researchers observing the ice shelf, the calving occurred sometime between Monday and Wednesday.<br></p><p>The landscape of the Antarctic Peninsula has been "changed forever," the researchers <a href="http://www.projectmidas.org/" target="_blank">said</a>. The calving leaves the Larsen C Ice Shelf reduced in area by more than 12 percent, its smallest size ever recorded. </p><p>The widening crack had been developing over the past year. Project MIDAS <a href="http://www.projectmidas.org/blog/multiple-branches/" target="_blank">said</a> last week that the massive iceberg was hanging onto the main shelf by just a 3-mile thread. "Multiple rift tips" had also formed, meaning a number of smaller icebergs could also splinter off.</p><p><span></span>"We have been anticipating this event for months, and have been surprised how long it took for the rift to break through the final few kilometers of ice. We will continue to monitor both the impact of this calving event on the Larsen C Ice Shelf, and the fate of this huge iceberg," Professor Adrian Luckman of Swansea University and lead investigator of the project said. <br></p><p>"The iceberg is one of the largest recorded and its future progress is difficult to predict. It may remain in one piece but is more likely to break into fragments. Some of the ice may remain in the area for decades, while parts of the iceberg may drift north into warmer waters," Luckman added. </p><p>The new configuration of Larsen C could potentially make it less stable. There's a chance it could follow the example of its neighbor, Larsen B, which rapidly broke apart in 2002 after a similar rift-induced calving event in 1995, the researchers said. </p><p>"In the ensuing months and years, the ice shelf could either gradually regrow, or may suffer further calving events which may eventually lead to collapse—opinions in the scientific community are divided. Our models say it will be less stable, but any future collapse remains years or decades away," Luckman said. </p><p>The iceberg will have no immediate impact on sea level since it was already floating before it calved. However, as these ice shelves disintegrate, the land-locked glaciers they hold back may begin sliding into the sea. </p><p>"Although this is a natural event, and we're not aware of any link to human-induced <a href="https://www.ecowatch.com/climate-change/">climate change</a>, this puts the ice shelf in a very vulnerable position," explained Dr. Martin O'Leary, a Swansea University glaciologist and member of the MIDAS project team. "This is the furthest back that the ice front has been in recorded history. We're going to be watching very carefully for signs that the rest of the shelf is becoming unstable."</p>
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The rift in Larsen C. Photo credit: NASA
The widening crack in Antarctica's Larsen C Ice Shelf has grown even longer. An iceberg the size of Delaware is now precariously hanging on to the main ice shelf by 8 miles of ice.
<p>
Scientists with the Antarctic research group
<a href="http://www.projectmidas.org/" target="_blank">Project Midas</a> report that the rift lengthened by another 11 miles between May 25 and May 31 2017—"the largest jump since January" when the crack was <a href="https://www.ecowatch.com/new-crack-larsen-c-ice-shelf-2390678113.html">12 miles</a>.
</p><p>Until recently, the crack was running parallel to the edge of the ice shelf but it took a "significant" turn towards the ocean, "indicating that the time of calving is probably very close," the Project Midas team
<a href="http://www.projectmidas.org/blog/another-step-closer/" target="_blank">wrote</a>.
</p><p>As Project Midas scientist Martin O'Leary explained to <a href="https://ecowatchroar-secure.rebelmouse.com/core/dashboard/editor/In%20an%20email%20to%20Newsweek%20,%20Project%20Midas%20scientist%20Martin%20O'Leary%20said:%20%E2%80%9C%5BUntil%20now%5D%20the%20rift%20has%20been%20growing%20more%20or%20less%20parallel%20to%20the%20ice%20front,%20so%20the%20amount%20of%20ice%20connecting%20the%20berg%20to%20the%20shelf%20has%20been%20more%20or%20less%20constant.%20However,%20this%20time%20around%20the%20rift%20has%20curved%20towards%20the%20front,%20so%20there's%20now%20only%2013km%20%5Beight%20miles%5D%20remaining." target="_self">Newsweek</a>, "[Until now] the rift has been growing more or less parallel to the ice front, so the amount of ice connecting the berg to the shelf has been more or less constant. However, this time around the rift has curved towards the front, so there's now only 13km [eight miles] remaining."</p><p>"The rift has now fully breached the zone of soft 'suture' ice originating at the Cole Peninsula and there appears to be very little to prevent the iceberg from breaking away completely," Project Midas wrote. </p><p>After it finally breaks off, the Larsen C ice shelf will lose more than 10 percent of its area, leaving the ice front at "its most retreated position ever recorded."<br></p><p>
"This event will fundamentally change the landscape of the <a href="http://www.ecowatch.com/tag/antarctica">Antarctic Peninsula</a>," the team stated. "We have previously shown that the new configuration will be less stable than it was prior to the rift, and that Larsen C may eventually follow the example of its neighbor Larsen B, which disintegrated in 2002 after a similar rift-induced calving event."
</p><p>Calving events are normal, as NASA <a href="https://www.nasa.gov/press-release/nasa-study-shows-antarctica-s-larsen-b-ice-shelf-nearing-its-final-act" target="_blank">explained</a>, but "calving that happens faster than a shelf can re-advance can mean trouble for an ice shelf." </p><p>As <a href="http://www.ecowatch.com/antarctic-ice-melt-1986406994.html" target="_blank">EcoWatch reported previously</a>, two previous sections of the Larsen ice shelf have broken off and disappeared into the sea. Larsen A collapsed in 1995. Then in 2002, Larsen B began to rapidly break apart. Within six weeks, a 1,235 square mile chunk of ice slipped away, which scientists attributed to warmer air temperatures. Prior to that, the Larsen B ice shelf had been stable for 12,000 years.<br></p><p>It's unclear if Larsen C will respond in a similar ways. Project Midas is monitoring the development of the rift and will assess its ongoing impact on the ice shelf.<br></p><p>The loss of this portion of the ice shelf will not <a href="http://www.ecowatch.com/tag/sea-level-rise" target="_blank">raise sea levels</a> since it is already floating on the water. However, as these ice shelves disintegrate, the land-locked glaciers they hold back may begin sliding into the sea. If all of the ice the Larsen C ice shelf holds back slides into the ocean, it will raise sea levels globally by four inches.</p>
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An aerial view of the Larsen C ice rift. John Sonntag/NASA
A new branch has split off the widening crack in the Larsen C Ice Shelf in another sign of the ice's impending breakoff, scientists reported this week.
<p>British researchers monitoring the ice shelf using satellite technology spotted the new nine-mile-long branch, which runs about six miles below the original crack. The rift in the Larsen Ice Shelf, now about 111 miles long, grew by 17 miles between December and January of this year, and only 12 additional miles of ice remain attaching the calving ice to the larger shelf. </p><p>The coming breakoff, amounting to 10 percent of the ice shelf, could accelerate the further breakup of the ice shelf and "fundamentally change" the makeup of the <a href="http://www.ecowatch.com/tag/antarctica">Antarctic</a>.</p><p>"As of May 1, 2017, we have observed a significant change in the rift on the Larsen C ice shelf," wrote the Project Midas researchers on <a href="http://www.projectmidas.org/blog/a-new-branch/" target="_blank">their website</a>. </p><p>According to Project MIDAS, "there is not enough information to know whether the expected calving event on Larsen C is an effect of <a href="http://www.ecowatch.com/climate-change/" target="_blank">climate change</a> or not, although there is good scientific evidence that climate change has caused thinning of the ice shelf."</p><p>As <a href="http://www.ecowatch.com/antarctic-ice-melt-1986406994.html" target="_blank">EcoWatch reported previously</a>, the loss of this portion of the ice shelf will not <a href="http://www.ecowatch.com/tag/sea-level-rise">raise sea levels</a> as it is already floating on the water. However, as these ice shelves disintegrate, the land-locked glaciers they hold back may begin sliding into the sea. If all of the ice the Larsen C ice shelf holds back slides into the ocean, it will raise sea levels globally by four inches.</p><p><strong>For a deeper dive:</strong></p><p><a href="https://www.washingtonpost.com/news/energy-environment/wp/2017/05/02/a-new-crack-in-one-of-antarcticas-biggest-ice-shelves-could-mean-a-major-break-is-near/?utm_term=.ee94dc708822" target="_blank">Washington Post</a>, <a href="https://www.usatoday.com/story/tech/sciencefair/2017/05/02/new-crack-forms-antarctic-ice-shelf/101195464/" target="_blank">USA Today</a>, <a href="http://mashable.com/2017/05/02/second-crack-larsen-c-ice-shelf-largest-iceberg/#77FtP0c.BmqK" target="_blank">Mashable</a>, <a href="http://www.climatecentral.org/news/larsen-c-crack-new-branch-21409" target="_blank">Climate Central</a></p><p><em>For more <a href="http://ecowatch.com/climate-change-news/" target="_blank">climate change</a> and <a href="http://ecowatch.com/business/renewables/" target="_blank">clean energy</a> news, you can follow Climate Nexus on <a href="https://twitter.com/ClimateNexus" target="_blank">Twitter</a> and <a href="https://www.facebook.com/ClimateNexus/" target="_blank">Facebook</a>, and sign up for daily <a href="http://climatenexus.us4.list-manage1.com/subscribe?u=d1f5797e59060083034310930&id=7c84c08aaa" target="_blank">Hot News</a>.</em></p>
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The growing rift in the Antarctic Peninsula has now lengthened to 110 miles, meaning that the Larsen C ice shelf is now connected to the main ice shelf by only a 12-mile "thread," USA TODAY reports.
<p>The <a href="https://www.bas.ac.uk/" target="_blank">British Antarctic Survey</a> determined that the crack has expanded by 50 miles since 2011.</p><p>"It is particularly hard to predict when it will occur," Adrian Luckman of <a href="http://www.projectmidas.org/" target="_blank">Project MIDAS</a> told USA TODAY about the eventual calving, which would create a Delaware-sized iceberg. "I am quite surprised as to how long it is holding on!"</p><p>"The rift (or crack) has continued to open, and the berg continues to drift outward at a very consistent rate," Luckman added. </p><p>However, he noted that the crack has not grown longer in recent weeks. <br></p><p>As <a href="http://www.ecowatch.com/antarctic-ice-melt-1986406994.html" target="_blank">EcoWatch mentioned previously</a>, the loss of this portion of the <a href="http://www.ecowatch.com/tag/sea-ice">ice shelf</a> will not raise sea levels as it is already floating on the water. However, as these ice shelves disintegrate, the land-locked glaciers they hold back may begin sliding into the sea. If all of the ice the Larsen C ice shelf holds back slides into the ocean, it will raise sea levels globally by four inches.</p><p><span></span><a href="http://www.projectmidas.org/blog/aerial-footage-of-the-rift-on-larsen-c/" target="_blank">According</a> to Project MIDAS, "there is not enough information to know whether the expected calving event on Larsen C is an effect of <a href="http://www.ecowatch.com/climate-change/">climate change</a> or not, although there is good scientific evidence that climate change has caused thinning of the ice shelf." <br></p><p><u><a href="https://www.theguardian.com/environment/2015/mar/31/potential-record-high-temperature-in-antarctica-alarms-scientists" target="_blank">Temperatures at the Antarctic Peninsula</a></u>, where the Larsen ice shelf is found, have risen by 2.5 degrees Celsius in the past 50 years.</p><p>Antarctica's ice shelves are <a href="http://www.ecowatch.com/ocean-warming-antarctica-glaciers-melting-2064507190.html">indeed melting rapidly</a> as ocean waters warm. <a href="http://www.ecowatch.com/community/climate_nexus">Climate Nexus</a> reported in October that three glaciers in West Antarctica have undergone "intense unbalanced melting," risking their stability and further acceleration of <a href="http://www.ecowatch.com/tag/sea-level-rise">sea level rise</a>.</p><p><a href="http://www.nature.com/articles/ncomms13243" target="_blank">Research</a> published in <em>Nature Communications</em> found that the Smith, Pope and Kohler glaciers in the Amundsen Sea embayment collectively lost about 1,000 feet of ice from 2002 to 2009. </p>
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A 70-mile long crack in the Larsen C ice shelf grew another shocking 11 miles in December alone. That leaves just 12 miles before an iceberg the size of Delaware snaps off into the Southern Ocean.
Delaware-Sized Chunk of Ice Could Dislodge from #Antarctic Shelf via @EcoWatch #climate https://t.co/nHjoAThctF— Dan Zukowski (@Dan Zukowski)1472243166.0
"The Larsen C Ice shelf in Antarctica is primed to shed an area of more than 5000 square kilometers [approx. 3,100 square miles] following further substantial rift growth," wrote the Project MIDAS team, which has been studying the ice shelf.
"After a few months of steady, incremental advance since the last event, the rift grew suddenly by a further 18 kilometers [about 11 miles] during the second half of December 2016."
During the last Antarctic winter, the rift averaged about three miles per month of growth. In December, NASA released a set of images that found the crack measured 70 miles in length, 300 feet wide and one-third of a mile deep.
Stunning Photos Show Huge Crack in Antarctic Ice Shelf https://t.co/Pc1i7H0daP @WRIClimate @CarbonFixIt— EcoWatch (@EcoWatch)1481850021.0
The sudden acceleration of the split in the ice has scientists convinced that a massive calving event is imminent.
"If it doesn't go in the next few months, I'll be amazed," Professor Adrian Luckman, project leader from Swansea University, told BBC News.
By itself, the iceberg that is set to break off won't lead to a rise in sea levels, as the ice shelf already floats on the ocean. However, the Larsen ice shelf acts as a buttress against continental glaciers that could then be free to slide into the sea. BBC reports that if all the ice that Larsen C holds back were released into the ocean, global waters would rise by 10 cm, or four inches.
Globally, sea levels have risen about eight inches since 1901. Its effects can be seen in increased flooding in South Florida, coastal erosion in Louisiana, intrusion of seawater into ground aquifers and stronger storm surges such as those seen in Superstorm Sandy.
#Louisiana Faces Faster Levels of Sea-Level Rise Than Any Other Land on Earth https://t.co/zCuAWpcH7U @NRDC @RobertKennedyJr @Waterkeeper— EcoWatch (@EcoWatch)1483558863.0
Antarctica—which holds 90 percent of the Earth's fresh water—is losing about 92 billion tons of ice per year. The rate of loss has doubled from 2003 to 2014.
Long-term satellite observations show that Antarctic glaciers are rapidly retreating. A separate rift in the East Antarctic is forcing a British research station to relocate.
Robert Swan Leads Antarctic Expedition to Show Effects of #ClimateChange http://t.co/OtH32KIJX7 @robertswan2041 http://t.co/UBG4ayYUZs— EcoWatch (@EcoWatch)1425501873.0
The Larsen C is the latest section of the huge ice shelf to break off. Larsen A collapsed in 1995. In 2002, Larsen B began to break apart. Within six weeks, a 1,235 square mile chunk of ice slipped away.
When the Larsen C ice shelf breaks off, it "will fundamentally change the landscape of the Antarctic Peninsula," said the U.K.-based Project MIDAS team.