Warming ocean water undercuts Antarctic ice shelves

“Upside-down rivers” of warm ocean water threaten the stability of floating ice shelves in Antarctica, according to a new study led by researchers at the National Snow and Ice Data Center published today in Nature Geoscience. The study highlights how parts of Antarctica’s ice sheet may be weakening due to contact with warm ocean water.

“We found that warm ocean water is carving these ‘upside-down rivers,’ or basal channels, into the undersides of ice shelves all around the Antarctic continent. In at least some cases these channels weaken the ice shelves, making them more vulnerable to disintegration,” said Karen Alley, a graduate research assistant at NSIDC and lead author of the study. Alley is also a Ph.D. student in the University of Colorado Boulder’s Department of Geological Sciences.

Ice shelves are thick floating plates of ice that have flowed off the Antarctic continent and spread out onto the ocean. As ice shelves flow out to sea, they push against islands, peninsulas, and bedrock bumps known as “pinning points.” Contact with these features slows the flow of grounded ice off the continent. While ice shelves take thousands of years to grow, previous work has shown that they can disintegrate in a matter of weeks. If more ice shelves disintegrate in the future, loss of contact with pinning points will allow ice to flow more rapidly into the ocean, increasing the rate of sea level rise.

“Ice shelves are really vulnerable parts of the ice sheet, because climate change hits them from above and below,” said Ted Scambos, NSIDC lead scientist and study co-author. “They are really important in braking the ice flow to the ocean.”

The features form as buoyant plumes of warm and fresh water rise and flow along the underside of an ice shelf, carving channels much like upside-down rivers. The channels can be tens of miles long, and up to 800 feet “deep.”

When a channel is carved into the base of an ice shelf, the top of the ice shelf sags, leaving a visible depression in the relatively smooth ice surface. Alley and her colleagues mapped the locations of these depressions all around the Antarctic continent using satellite imagery, as well as radar data that images the channels through the ice, mapping the shape of the ice-ocean boundary.

The team also used satellite laser altimetry, which measures the height of an ice shelf surface with high accuracy, to document how quickly some of the channels were growing. The data show that growing channels on the rapidly melting Getz Ice Shelf in West Antarctica can bore into the ice shelf base at rates of approximately 10 meters (33 feet) each year.

The mapping shows that basal channels have a tendency to form along the edges of islands and peninsulas, which are already weak areas on ice shelves. The team observed two locations where ice shelves are fracturing along basal channels, clear evidence that basal channel presence can weaken ice shelves to the point of breaking in vulnerable areas.

While no ice shelves have completely disintegrated due to carving by basal channels, the study points to the need for more observation and study of these features, said co-author Helen Amanda Fricker of Scripps Institution of Oceanography at UC San Diego. “It's feasible that as ocean temperatures around Antarctica continue to rise, melting in basal channels could contribute to increased erosion of ice shelves from below.”

The study, “Impacts of warm water on Antarctic ice shelf stability through basal channel formation,” was led by University of Colorado Boulder Ph.D. student Karen Alley, who worked with coauthors Ted Scambos of NSIDC and Matthew Siegfried and Helen Amanda Fricker of Scripps Institution of Oceanography, UC San Diego. Their work was funded in part by NASA and the U.S. Geological Survey. More

Contacts

Jane Beitler,Communications, National Snow and Ice Data Center, press@nsidc.org, +1-303-492-1497
Brittany Hook, Communications Coordinator, Scripps Institution of Oceanography, scrippsnews@ucsd.edu, 858-534-3624

 

Why Greenland’s “Dark Snow” Should Worry You

Jason Box’s research into Greenland’s dark snow raises more concerns about climate change.

Jason Box knows ice. That’s why what’s happened this year concerns him so much. Box just returned from a trip to Greenland. Right now, the ice there is … black:

The ice in Greenland this year isn’t just a little dark—it’s record-setting dark. Box says he’s never seen anything like it. I spoke to Box by phone earlier this month, just days after he returned from his summer field research campaign.

“I was just stunned, really,” Box told me.

The photos he took this summer in Greenland are frightening. But their implications are even more so. Just like black cars are hotter to the touch than white ones on sunny summer days, dark ice melts much more quickly.

As a member of the Geological Survey of Denmark and Greenland, Box travels to Greenland from his home in Copenhagen to track down the source of the soot that’s speeding up the glaciers’ disappearance. He aptly calls his crowdfunded scientific survey Dark Snow.

There are several potential explanations for what’s going on here. The most likely is that some combination of increasingly infrequent summer snowstorms, wind-blown dust, microbial activity, and forest fire soot led to this year’s exceptionally dark ice. A more ominous possibility is that what we’re seeing is the start of a cascading feedback loop tied to global warming. Box mentions this summer’s mysterious Siberian holes and offshore methane bubbles as evidence that the Arctic can quickly change in unpredictable ways.

This year, Greenland’s ice sheet was the darkest Box (or anyone else) has ever measured. Box gives the stunning stats: “In 2014 the ice sheet is precisely 5.6 percent darker, producing an additional absorption of energy equivalent with roughly twice the US annual electricity consumption.”

Perhaps coincidentally, 2014 will also be the year with the highest number of forest fires ever measured in Arctic.

Box ran these numbers exclusively for Slate, and what he found shocked him. Since comprehensive satellite measurements began in 2000, never before have Arctic wildfires been as powerful as this year. In fact, over the last two or three years, Box calculated that Arctic fires have been burning at a rate that’s double that of just a decade ago. Box felt this finding was so important that he didn’t want to wait for peer review, and instead decided to publish first on Slate. He’s planning on submitting these and other recent findings to a formal scientific journal later this year.

Box’s findings are in line with recent research that shows the Arctic is in the midst of dramatic change.

A recent study has found that, as the Arctic warms, forests there are turning to flame at rates unprecedented in the last 10,000 years. This year, those fires produced volumes of smoke and soot that Box says drifted over to Greenland.

In total, more than 3.3 million hectares burned in Canada’s Northwest Territories alone this year—nearly 9 times the long term average—resulting in a charred area bigger than the states of Connecticut and Massachusetts combined. That figure includes the massive Birch Creek Complex, which could end up being the biggest wildfire in modern Canadian history. In July, it spread a smoke plume all the way to Portugal.

In an interview with Canada’s National Post earlier this year, NASA scientist Douglas Morton said, “It’s a major event in the life of the earth system to have a huge set of fires like what you are seeing in Western Canada.”

Box says the real challenge is to rank what fraction of the soot he finds on the Greenland ice is from forest fires, and what is from other sources, like factories. Box says the decline of snow cover in other parts of the Arctic (like Canada) is also exposing more dirt to the air, which can then be more easily transported by the wind. Regardless of their ultimate darkening effect on Greenland, this year’s vast Arctic fires have become a major new source of greenhouse gas emissions from the thawing Arctic. Last year, NASA scientists found “amazing” levels of carbon dioxide and methane emanating from Alaskan permafrost.

Earlier this year, Box made headlines for a strongly worded statement along these lines:

That tweet landed Box in a bit of hot water with his department, which he said now has to approve his media appearances. Still, Box’s sentiment is inspiring millions. His “f’d” quote is serving as the centerpiece of a massive petition (with nearly 2 million signatures at last count) that the activist organization Avaaz will deliver to “national, local, and international leaders” at this month’s global warming rally in New York City on Sept. 21. More

 

 

 

 

‘There Will Be No Water’ by 2040? Researchers Urge Global Energy Paradigm Shift

The world risks an “insurmountable” water crisis by 2040 without an immediate and significant overhaul of energy consumption and demand, a research team reported on Wednesday.

“There will be no water by 2040 if we keep doing what we're doing today,” said Professor Benjamin Sovacool of Denmark's Aarhus University, who co-authored two reports on the world's rapidly decreasing sources of freshwater.

Many troubling global trends could worsen these baseline projected shortages. According to the report, water resources around the world are “increasingly strained by economic development, population growth, and climate change.” The World Resources Institute estimates that in India, “water demand will outstrip supply by as much as 50 percent by 2030, a situation worsened further by the country's likely decline of available freshwater due to climate change,” the report states. “[P]ower demand could more than double in northern China, more than triple in India, and increase by almost three-quarters in Texas.”

“If we keep doing business as usual, we are facing an insurmountable water shortage — even if water was free, because it's not a matter of the price,” Sovacool said. “There's no time to waste. We need to act now.”

In addition to an expanding global population, economic development, and an increasing demand for energy, the report also finds that the generation of electricity is one of the biggest sources of water consumption throughout the world, using up more water than even the agricultural industry. Unlike less water-intensive alternative sources of energy like wind and solar systems, fossil fuel-powered and nuclear plants need enormous and continued water inputs to function, both for fueling thermal generators and cooling cycles.

The reports, Capturing Synergies Between Water Conservation and Carbon Dioxide Emissions in the Power Sectorand A Clash of Competing Necessities: Water Adequacy and Electric Reliability in China, India, France, and Texas and published after three years of research by Aarhus University, Vermont Law School and CNA Corporation, show that most power plants do not even log how much water they use to keep the systems going.

“It's a huge problem that the electricity sector do not even realize how much water they actually consume,” Sovacool said. “And together with the fact that we do not have unlimited water resources, it could lead to a serious crisis if nobody acts on it soon.”

Unless water use is drastically minimized, the researchers found that widespread drought will affect between 30 and 40 percent of the planet by 2020, and another two decades after that will see a severe water shortage that would affect the entire planet. The demand for both energy and drinking water would combine to aggressively speed up drought, which in turn could exacerbate large-scale health risks and other global development problems.

“The policy and technology choices made to meet demand will have immense implications for water withdrawals and consumption, and may also have significant economic, human health, and development consequences,” the report states.

The research says that utilizing alternative energy sources like wind and solar systems is vital to mitigating water consumption enough to stave off the crisis. “Unsubsidized wind power costs… are currently lower than coal or nuclear and they are continuing to drop,” the report states. When faced with its worst drought in 2011, Texas got up to 18 of its electricity from wind power and was able to avoid the kind of rolling blackouts that plague parts of China, where existing water shortages prevent power plants from operating.

An equally important step would be to shutter “thirsty” fossil fuel facilities in areas that are already experiencing water shortages, like China and India, where carbon emissions can be significantly more impactful.

“[We] have to decide where we spend our water in the future,” Sovacool said. “Do we want to spend it on keeping the power plants going or as drinking water? We don't have enough water to do both.” More

 

The Sunswift eVe solar-powered car broke a 26-year-old land speed record for electric vehicles

The Sunswift eVe solar-powered car broke a 26-year-old land speed record for electric vehicles on Wednesday at the Australian Automotive Research Center in Victoria. While the record still has to be ratified by the Fédération Internationale de l’Automobile, it would make eVe the fastest electric car to ever compete a 500 km set distance course by a significant margin, Gizmodo reported. The previous record, set in 1988, was an average speed of 73 kilometers per hour; the Sunswift eVe reached 100 km per hour average over the 500 km course.

Sunswift eVe, designed and built by students at the University of New South Wales, seeks to overcome the traditional obstacles that have impeded solar-powered cars, namely, offering both speed and range in the same vehicle.

“There are many solar cars out there with a long range, and many other solar cars capable of even higher speeds,” Rob Ireland, business team leader at Sunswift, told International Business Times. “However, we’re trying to do something ground-breaking and overcome both.”

The zero-emission solar and battery storage electric vehicle is capable of covering 800 km on a single charge and has a top speed of 140 km per hour (87 miles per hour). The car’s solar panels have an 800-watt output and when the sun isn’t shining, eVe relies on its battery pack, reducing drivers’ range anxiety. The car’s motor, “supplied by Australian national science agency CSIRO, operates at 97 percent efficiency, meaning eVe consumes as much power as a kitchen toaster,” according to IB Times.

For Wednesday’s record attempt, the solar panels on the roof and hood were used to charge the battery, but were covered for the actual run, as the attempt had to be completed on a single charge.

While the Sunswift eVe is not fully road legal, the team believes that isn’t far out of reach, telling Renew Economy they hope to have the vehicle on Australian roads within the year as “a symbol for a new era of sustainable driving.” And Ireland said the practicality of the two-seat, four-wheel car is unmatched among solar-powered vehicles.

In the run-up to their attempt at the land speed record, project director and third-year engineering student Hayden Smith explained to Renew Economy why it was so significant. “Five hundred kilometers is pretty much as far as a normal person would want to drive in a single day,” Smith said. “It’s another demonstration that one day you could be driving our car.” More

 

Surviving the 21st Century

Surviving the 21st Century


Published on May 28, 2014 • Professor Noam Chomsky Institute Professor & Professor of Linguistics (Emeritus), Massachusetts Institute of Technology addressed this question of global significance in a special Durham Castle Lecture on 22nd May.

Which U.S. City Will Be the First Submerged by Climate Change?

A new Climate Central report shows which U.S. cities’ fates are locked in by sea-level rise. The long list of 1,400 cities includes not only obvious coastal candidates like Miami and New Orleans, but also inland cities such as Sacramento. They’re doomed to drown by 2100 even if carbon emissions immediately—like right now—drop to zero.

Representative Henry Waxman (D-CA), a longstanding climate champion, tells TakePart: “As this report makes clear, climate change is no longer an issue for ‘later.’ Climate change is already affecting the United States and the window for effective action is closing fast. We must act now to protect the planet for our children and future generations.”

Ben Strauss, one of the scientists behind the new report, began with a study that found for every degree Fahrenheit of global warming due to carbon pollution, global average sea-level will rise by about 4.2 feet in the long run. When multiplied by the current rate of carbon emissions, and the best estimate of global temperature sensitivity to pollution, this translates to a long-term sea-level rise commitment that is now growing at about one foot per decade. Strauss then analyzed the growth of the locked-in amount of sea-level rise and plotted it against a map of the United States.

Carbon pollution to date has already locked in more than four feet of sea-level rise past today’s levels, Strauss finds. That’s enough, at high tide, to submerge more than half of today’s population in 316 coastal cities and towns, home to 3.6 million people, in the lower 48 states.

“We have two sea levels: the sea level of today, and the far higher sea level that is already being locked in for some distant tomorrow,” Strauss writes.

Rising tides have already harmed some coastal towns.

“In Rhode Island, we’ve already seen almost 10 inches of sea-level rise at the Newport tide gauge since the 1930s, making coastal communities more vulnerable to floods, erosion, and the kind of property damage we saw during Hurricane Sandy. We must take immediate steps to limit the carbon pollution that is contributing to sea-level rise, and help coastal areas prepare for new realities,” Senator Sheldon Whitehouse tells TakePart.

To the surprise of absolutely no one who has seen An Inconvenient Truth, Florida is the most threatened state. Louisiana, North Carolina, and New Jersey are also high on the list. Strauss didn’t consider the impact of armoring or defending cities in preparing his report, but notes that New Orleans may be defensible through sea walls, while Miami is indefensible because of its porous bedrock geology.

Although California’s Sacramento and Stockton are thought of as inland cities, they’re connected to the Pacific Ocean through the Sacramento-San Joaquin Delta, a complex maze of marshes and levees. By 2040, 25 percent of Stockton will be underwater at high tide. By 2060, the same will be true of Sacramento, California’s state capitol. Coastal California cities such as Huntington Beach, the original Orange County Surf City, and Palo Alto, home of Stanford University, will likewise be inundated.

Other cities projected to be 50 percent underwater: Galveston, Texas, by 2030; Norfolk, Virginia; and Coral Gables, Florida, by 2044. More