Quantcast
Climate

Scientists Alarmed as Delaware-Sized Iceberg Breaks Off Antarctic Ice Shelf

By Ilissa Ocko and Mason Fried

Scientists watched with alarm this week as the fourth-largest ice shelf in Antarctica rapidly broke apart, causing an enormous, Delaware-size iceberg to float into the Southern Ocean.


After observing an anomalous rift widening across a section of the so-called Larsen C ice shelf for the past several years, researchers are left with some critical questions: What are this event's broader consequences for the Antarctic ice sheet, what happens next, and—importantly—what role did climate change play here?

For now, this event serves as yet another reminder that Antarctica is changing rapidly—and that action to curb rising global temperatures is critical.

Antarctica: A frontline for climate change

So far, scientists have been hesitant to attribute the Larsen C ice shelf breakup to rising global temperatures.

Indeed, such events—known to scientists as "calving"—occur naturally and are essential for maintaining ice shelf balance. Without them, ice shelves would grow unabated to cover large swaths of the Southern Ocean.

Still, the magnitude and timing of this ice loss warrants attention.

The Antarctic Peninsula, where the Larsen ice shelves reside, has long been viewed as a frontline for climate change. Warming in the peninsula exceeds the global average, glaciers there are retreating, and two other ice shelves on the peninsula already collapsed over the past couple of decades after being stable for thousands of years.

Such changes will help raise global sea levels by three to six feet by 2100, projections show, affecting dense coastal communities along our Eastern Seaboard and across the globe.

Ice breakup starts chain reaction

We do know that this calving event could set in motion a string of chain reactions that further destabilize the ice shelf and surrounding glaciers, and ultimately contribute to global sea level rise.

Ice shelves are floating extensions of grounded glaciers and ice sheets that, importantly, buttress and impede inland ice flow. When an ice shelf collapses or becomes weaker, this defense disappears, allowing inland glaciers to accelerate downslope and transport more ice to the ocean, which can quickly affect sea level.

Scientists worry that the remnant Larsen C ice shelf will now be at considerable risk of further breakup.

The new calving event reduced the ice shelf area by more than 10 percent, leaving behind an ice shelf that is inherently unstable. This can, in turn, trigger new ice cracks and rifting, and cause more icebergs to break off—further increasing the possibility of runaway ice loss amid rising global temperatures.

Whether or not this latest calving event will be attributed to climate change, it's safe to say that it will make the region more vulnerable to the impacts of global warming.

Climate change caused 2002 ice shelf collapse

The Larsen C ice shelf, named for a Norwegian whaling vessel captain who sailed the Southern Sea in the late 1800s, has two smaller northern neighbors known as Larsen A and Larsen B—both of which collapsed in the past 23 years.

Those events taught us that ice sheets, landscapes we used to think of as stable and slow to change, can actually transform rapidly.

The Larsen B collapse was particularly dramatic, with nearly the entire ice shelf disintegrating during a three-week period in 2002 after remaining stable for at least 10,000 years.

The speed of that event was unprecedented and attributed directly to increasing atmospheric warming, although rising ocean temperatures and long-term ice loss from surrounding glaciers may also have played a role.

A hint of what's to come?

After the Larsen B shelf collapse, researchers observed dramatic increases in glacier speed, thinning and ice transfer to the ocean.

Some researchers are already drawing parallels between this week's Larsen C collapse and the series of events that led to the eventual collapse of Larsen B. The latter experienced a similar large calving event in 1995 that foreshadowed further retreat and widespread disintegration in 2002.

While it remains to be seen if and when Larsen C will meet the same fate, warning signs are already in place. What's happening to the Larsen ice shelves could, in fact, be a proxy for what's to come across even larger sections of the Antarctic ice sheet unless we take action to slow warming.

Show Comments ()
Sponsored
African elephant. USFWS

Lawsuit Challenges Trump Administration Over New Elephant and Lion Trophy Policies, Still in Effect Despite Trump's Tweets

The Center for Biological Diversity and Natural Resources Defense Council sued the Trump administration Monday for allowing U.S. hunters to import elephant and lion trophies from Zimbabwe. The lawsuit aims to protect animals and resolve confusion created by the administration's contradictory announcements in recent days.

The suit comes days after the U.S. Fish and Wildlife Service abruptly reversed an Obama-era ban on elephant trophy imports based on catastrophic elephant population declines. Fish and Wildlife also recently greenlighted lion trophy imports from Zimbabwe, despite the controversial killing of Cecil the Lion in Zimbabwe in 2015.

Keep reading... Show less
Below the Mackinac bridge runs Enbridge Line 5, transporting 23 Million gallons of oil and liquid gas every day. Conor Mihell

Four Questions About the New Line 5 Pipeline Report

By Beth Wallace

In June, the state of Michigan released a draft report on alternatives to Enbridge's Line 5 pipeline, which pumps up to 23 million gallons of oil and natural gas liquids (NGLs) per day along the bottom of the Straits of Mackinac. The draft report, written by Dynamic Risk, was met with heavy criticism from all sides, and the National Wildlife Federation joined with many others to suggest numerous and substantive changes. On Nov. 20, the final alternatives report was released to the public. As per an agreement with the state to obtain funding for the report, Enbridge has had five days to review this report before it is released publicly.

Keep reading... Show less
USDA

Thanksgiving Dinner Is Cheapest in Years, But Are Family Farms Paying the Price?

By Sarah Reinhardt

Last week, the Farm Bureau released the results of its annual price survey on the cost of a typical Thanksgiving dinner. The grand total for a "feast" for 10 people, according to this year's shoppers? About 50 dollars ($49.87, if you want to be exact). That includes a 16-pound turkey at $1.40 per pound, and a good number of your favorite sides: stuffing, sweet potatoes, rolls with butter, peas, cranberries, a veggie tray, pumpkin pie with whipped cream, and coffee and milk.

After adjusting for inflation, the Farm Bureau concluded that the cost of Thanksgiving dinner was at its lowest level since 2013. Let's talk about what that means for farmers, and for all of us.

Keep reading... Show less

Would More People Ride the Bus if It Looked and Felt Like a Train?

By Jeff Turrentine

It moves through city thoroughfares, towering above automobile traffic. It makes frequent stops to pick up and drop off passengers. It has places to sit, places to stand, and—yes—rubber-tired wheels that go 'round and 'round, all through the town.

But don't call it a bus. It's a "trackless electric train."

Keep reading... Show less
Sponsored

Electric Car Sales Surge 63% Globally

Electric vehicles (EVs) continue to gain momentum on the world market.

Global sales of electric and hybrid cars are 63 percent higher than the same quarter last year, and up 23 percent from the second quarter, according to a Bloomberg New Energy Finance (BNEF) report.

Keep reading... Show less
Harvesting sugarcane in Brazil. Jonathan Wilkins / CC BY-SA

Jet Fuel From Sugarcane? It’s No Flight of Fancy

By Deepak Kumar, Stephen P. Long and Vijay Singh

The aviation industry produces two percent of global human-induced carbon dioxide emissions. This share may seem relatively small—for perspective, electricity generation and home heating account for more than 40 percent—but aviation is one of the world's fastest-growing greenhouse gas sources. Demand for air travel is projected to double in the next 20 years.

Airlines are under pressure to reduce their carbon emissions, and are highly vulnerable to global oil price fluctuations. These challenges have spurred strong interest in biomass-derived jet fuels. Bio-jet fuel can be produced from various plant materials, including oil crops, sugar crops, starchy plants and lignocellulosic biomass, through various chemical and biological routes. However, the technologies to convert oil to jet fuel are at a more advanced stage of development and yield higher energy efficiency than other sources.

Keep reading... Show less
Sponsored
Renewable Energy
"Eólica" or wind power plant in Guanacaste, Costa Rica. ICE Group / Twitter

Costa Rica Runs Entirely on Renewable Energy for 300 Days

Costa Rica has charted another clean energy accolade. So far this year, the Central American country has run on 300 days of 100 percent power generation from renewable energy sources, according to the Costa Rican Institute of Electricity (ICE), which cited figures from the National Center for Energy Control.

With six weeks left of 2017 to go, Costa Rica could easily surpass 300 days.

Keep reading... Show less
Popular
iStock

Starbucks Falls Short on Environmental Commitments

By Davis Harper

Since the early 1970s, Starbucks has held a special place in cupholders. Widespread infatuation with the company's caffeinated beverages has earned the coffee giant a storefront on almost every corner. With outposts in 75 countries and a whopping 13.3 million people enrolled in its loyalty rewards program, Starbucks has scorched nearly all of its closest competitors among major U.S. food brands (most of which aren't even coffee chains) in total market value.

With such reach and power comes tremendous responsibility. Starbucks touts its own corporate responsibility—claiming to be climate-change-aware and cognizant of its environmental cup-print—but how many latte-sippers know that their paper cup actually isn't recyclable and that it'll likely end up in a landfill? Might the knowledge that Starbucks's meat supply is pumped with antibiotics alter the market's appetite for the popular chicken and double-smoked bacon sandwich? Although the company prides itself on environmental awareness and progress toward sustainable products, multiple reports point to the mega-corporation's failure to live up to its own purported standards.

Keep reading... Show less
Sponsored

mail-copy

The best of EcoWatch, right in your inbox. Sign up for our email newsletter!