Tag Archives: greenland

Credit: British Antarctic Survey.

What Greenland’s landscape looks like without any ice

The most detailed map of Greenland’s topography was released this week by a team of British and American researchers. An accompanying video simulates what the massive island would look like if it were free of ice. Speaking of which, the new findings suggest that Greenland’s ice sheet has the potential to contribute more to global sea level rise than believed.

Credit: British Antarctic Survey.

Credit: British Antarctic Survey.

Greenland’s ice sheet is immense. Covering more than 660,000 square miles, thicker than a mile, and measuring a volume of 684,000 cubic miles, it would drown anything lower than 25 feet (~7.5 meters) above sea level were it to melt.

The new map carted by researchers at the British Antarctic Survey (BAS), the University of Bristol, and the University of California at Irvine (UCI), now offers a glimpse of what the island’s topography looks like under that huge blanket of ice.

We can see streams on top of valleys carved by water that used to flow well before the ice sheet even existed. The valley system creates perfect lubricating conditions for meltwater to run off and discharge into the ocean. What’s more, Greenland’s topography could foster the creation of more channels in the future, further speeding up the run-off.

Already, Greenland lost 269 billion tons of ice each year since 2002. According to an earlier study, meltwater sourced from Greenland’s ice sheet accounted for 25 percent of the global sea level rise in 2014.

This refined view also shows that Greenland’s ice sheet is thicker than previously thought, in some places by up to 100 meters.

“This new compilation of the 3-D landscape beneath the Greenland Ice Sheet provides the first seamless transition between the landmass and its adjoining seabed, and this gives scientists a bird’s eye view of the fringes of Greenland which are experiencing the most changes,” said BAS cartographer Peter Fretwell, who was involved in producing the printed map.

“What’s also surprising is that there is more ice and the bed is deeper in some places than previous maps suggest, so this means the total contribution from the ice sheet to global sea level rise would be 7.42 meters if it were to melt completely, slightly higher than previously calculated,” he added.

To make this detailed map, scientists employed data collected by different instruments operated by over 30 institutions worldwide. This includes data collected by satellites, airborne and ground-based radar, as well as seabed mapping from ships. A printed 1:3,500,000 scale version was presented this week at the American Geophysical Union meeting in New Orleans. A summy of the paper has been published in the journal Geophysical Research Letters.

“This map will improve our understanding of the ice-ocean interactions and how the ice sheet will evolve in a changing climate,” said glaciologist professor Jonathan Bamber at the University of Bristol who had a NERC-funded project to develop the printed map and data set.

Another study published on Wednesday in Science Advances found that in 2003, the ice sheet over Greenland suddenly began melting at a much faster rate. For instance, ice sheet run-off into the Tasersiaq catchment, which spans more than 2,500 square miles, increased by 80 percent compared to the average runoff rate in the decades prior. This suggests that global warming, though increasing gradually, can set off sharp, massive shifts in ice melt.

Helicopter View over Greenland. Credit: Wikimedia Commons, Christine Zenino.

Melt runoff is making the waters around Greenland less saline

Helicopter View over Greenland. Credit: Wikimedia Commons, Christine Zenino.

Helicopter View over Greenland. Credit: Wikimedia Commons, Christine Zenino.

Greenland’s ice sheet has been melting at a formidable rate for more than 30 years, much to the awe of climate scientists. The Greenland ice sheet is up to 3km thick and would raise sea levels by seven meters if it all melted into the sea. Right now, its adds roughly 1mm a year to the global average sea level. The consequences of all this massive volume of freshwater have never been properly understood but a new study paints a clearer picture, at least in one respect. According to researchers at Aarhus University, Denmark, melting ice has significantly altered the salinity content of coastal waters in Northeast Greenland. Nutrient flow, and thus ecosystems, are affected.

Fresher seas around Northeast Greenland

The Aarhus group employed 13-year-long in-site measurements recorded within the framework of the ‘Greenland Ecosystem Monitoring Program’ since 2003. The measurements performed in and outside the Young Sound sea unambiguously show surface water layers have become less saline by up to 1.5 salinity units per milliliter over the studied period. In other words, the researchers say, freshwater content grew from approximately 1 meter in 2003 to almost 4 meters in 2015.

The melted ice eventually makes its way into Greenland’s fjords from the ocean where it influences ecosystem structure. More freshwater at the surface of the water makes it more difficult for the nutrient-rich bottom layer to transport food to the upper layers where there’s sunlight. Both nutrients and sunlight are essential for plankton algae to bloom during the summer. Plankton sits at the bottom of the food chain, which all fish and marine ultimately rely on.

Changes in summer salinity from 2003 to 2015 in Young Sound, Saline water is increasingly being restricted to deeper layers due to inflow of freshwater from melting Greenland ice. Credit: Mikael Sejr

Changes in summer salinity from 2003 to 2015 in Young Sound, Saline water is increasingly being restricted to deeper layers due to inflow of freshwater from melting Greenland ice. Credit: Mikael Sejr

According to the authors of the new study, accelerated ice loss in the Arctic Ocean has driven up freshwater content considerably in the past decade, at a rate of approximately 600  km3 per year.  As far as the Greenland Ice Sheet is concerned, the ice loss rate has now doubled when compared to the rate experienced over 1983–2003.

“Nobody expected the ice sheet to lose so much mass so quickly,” said geophysicist Isabella Velicogna of the University of California, Irvine, earlier this year for Science Mag. “Things are happening a lot faster than we expected.”

Although the Arctic does indeed warm at twice the rate as the rest of the world, the precipitous erosion of Greenland ice can’t be explained by temperature alone. Most recently, scientists have come to understand that the unusually warm summers allow algae and microbes to grow on the wet surfaces of the ice sheet, where their pigments boost ice absorption of solar energy. Ideally, you want the ice sheet to be as white as possible for maximum light reflectivity but soot and dust carried from lower latitudes by currents have also darkened the ice. 

Melt streams on the Greenland Ice Sheet on July 19, 2015. Ice loss from the Greenland and Antarctic Ice Sheets as well as alpine glaciers has accelerated in recent decades. Credit: NASA photo by Maria-José Viñas.

Melt streams on the Greenland Ice Sheet on July 19, 2015. Ice loss from the Greenland and Antarctic Ice Sheets as well as alpine glaciers has accelerated in recent decades. Credit: NASA photo by Maria-José Viñas.

Besides driving global sea level rise and altering nutrient flow patterns, increased freshwater around Greenland may also impact local and global water circulation patterns. Freshwater dumped into Greenland’s coastal currents and into surface waters of the subarctic Atlantic might potentially influence deep water convection and meridional overturning circulation in the Atlantic ocean. This sort of climatic feedback mechanism is currently not included in the current Intergovernmental Panel on Climate Change (IPCC) models.

“Recent modeling studies have shown that meltwater from East Greenland may be efficiently transported to the Labrador Sea. Combined with the decreasing salinity trend in our data it suggests that a signal of ocean freshening is being transported downstream by a nearshore component of the East Greenland current and will contribute to the freshwater content in the subarctic Atlantic,” the authors reported in the journal Scientific Reports. 

Much of the ice loss from Greenland to date can be pinned to glaciers in West and Southeast Greenland. Since the rate is lower in glaciers in Northeast Greenland, the authors are worried that salinity could be even lower around other parts of coastal Greenland.

Aerial photos show Greenland deltas growing due to climate change

While climate change and human exploitation are drowning many deltas around the world, Greenland is experiencing the opposite: warming temperatures enabled its deltas to thrive.

The land–water boundary is drawn where the high-water line (a) can be identified. Presence of snowcover (b) or icebergs (c) aids the identification process. Mouth bars (d) are included as part of the delta extent. Image credits: Bendixen et al / Nature, via Google Earth.

A team of researchers which included Mette Bendixen from the University of Copenhagen and Lars L. Iversen from the University of Colorado Boulder analyzed aerial photos from the past 75 years. They started with photos taken by the US military during World War II and compared them to what we see today.

“We examined 121 deltas by looking at historical aerial photos taken by the American army during the Second World War” Bendixen said. “We compared these with modern satellite photos. In this way, we have been able to track changes in the Greenland deltas and see what has happened over the last 75 years.”

 

Visualization of the main terrestrial and marine drivers influencing delta changes. Numbers refer to different sections. Credits: Mette Bendixen et al / Nature.

They found that the deltas had remained stable from the 1940s to 1980s, but prograded (the growth of a river delta farther out into the sea) in a warming Arctic from the 1980s to 2010s. Since human activities are virtually inexistent in the area, this effect is attributed exclusively to environmental changes — namely, global warming.

“Our study shows how climate change affects environmental processes in the Arctic landscape. As a consequence of the warmer temperatures, more sediment is transported out to the coast. At the same time, the open-water period has been extended, and the material is therefore deposited in the deltas. And in this way, the deltas are growing,” says Associate Professor Aart Kroon, corresponding author.

Climate change isn’t a uniform process. We talk about a 1 C increase in global temperatures, but that doesn’t mean that all areas of the Earth will warm by 1C. Some will warm more, some less. The Arctic areas are among those who heat up more, which makes their coastal areas (and subsequently, the deltas) highly vulnerable. Places such as Alaska, Siberia, and western Canada are suffering great coastal erosion, but the Greenland deltas are advancing into the sea. This is quite unexpected and the net impact of this process is still unclear.

The evolution of these deltas is largely governed by two factors: the freshwater runoff and associated sediment load from the catchment, and by the waves and tide from the receiving basin. As temperatures rise (especially above 0 °C), freshwater runoff increases, causing the progradation researchers found.

Journal Reference: Mette Bendixen et al. Delta progradation in Greenland driven by increasing glacial mass loss. doi:10.1038/nature23873

 

Greenland is getting darker, increasing fears about global warming and sea level rise

Researchers fear that the darkening of Greenland will create a feedback loop with severe results.

Greenland’s pristine landscapes might become riddled with algae. Image via NASA.

The snowball effect — we often use it as a metaphor for something that starts off small but then builds up on itself more and more, until it becomes massive. Nature often works like that; after all, the snowball is, above all, a natural metaphor. But there’s more to snow than just rolling balls. Take albedo for example.

Albedo is a measure of how much solar energy the Earth (or any body for that matter) reflects back. The whiter and object is, the more energy it reflects. The darker it is, the more energy it absorbs. As you can imagine, snow is pretty white; it’s one of the whitest things on Earth. As snow melts, it exposes either the underlying rock or the vegetation that takes its place — either way, something darker. As a result, even more solar energy is absorbed and even more snow melts, and so on. This is what we call a feedback loop, and it’s what is happening nowadays in Greenland, leaving researchers extremely worried.

A five-year project called Black and Bloom wants to have a deeper look at that. They want to mix local data with computer models to predict how this change in albedo will contribute to rising sea levels. Greenland’s ice sheet alone contributes to 1mm a year to rising sea levels, and things may even be worse than we thought.

New data is showing that Greenland is riddled with dark-green patches of algae, bacteria, and minerals. Prof Martyn Tranter of Bristol University, who is leading the project, told the BBC:

“People are very worried about the possibility that the ice sheet might be melting faster and faster in the future. We suspect that in a warming climate these dark algae will grow over larger and larger parts of the Greenland ice sheet and it might well be that they will cause more melting and an acceleration of sea level rise. Our project is trying to understand just how much melting might occur.”

To make things even more complex, recent data has shown that most of this dark matter, once thought to be rock or soot, is actually biological. Algae is starting to assert dominance more and more, but for once, no one’s really happy to see natural plant life expand. How does the biological factor play into climate models, which tend to treat all factors as un-living? We don’t really know, but it might be worse.

In a paper recently published in Science Advances, Stefan Hofer, a PhD student at Bristol, analyzed data over 20 years and found a 15% decrease in cloud cover over Greenland in the summer months. This may be particularly significant considering the emerging algae. While temperature is certainly one of the main drivers of melting, clearer skies also contribute. But clearer skies do more than just melt ice and snow, they offer more energy to the algae, which can encourage them to grow even more. It’s basically a feedback loop on steroids. The clear weather acts on two fronts, adding an extra punch to the snowball effect researchers were already predicting.

The consequences of this effect are not yet understood. Greenland’s ice sheet is up to 3km thick and would raise sea levels by seven meters if all of it would melt into the sea. Of course, no one’s saying that will happen now or in the next decades, but until 2100, global sea levels are expected to rise by several cm, and just a few cm can wreak havoc on the world’s coasts.

Journal Reference: Stefan Hofer, Andrew J. Tedstone, Xavier Fettweis and Jonathan L. Bamber — Decreasing cloud cover drives the recent mass loss on the Greenland Ice Sheet. DOI: 10.1126/sciadv.1700584

greenland-1962999_960_720

Global sea levels rose 50% faster than two decades ago because of Greenland’s melting ice sheet

The rate of global sea level rise has increased by about 50 percent in just the last two decades, according to an international team of researchers. In 1993, global sea levels increased from a rate of 2.2 millimeters/year to 3.3 millimeters/year in 2014. The dramatic increase is believed to be mostly caused by melting of Greenland’s ice sheet.

greenland-1962999_960_720

The Greenland Ice Sheet contributed 5 percent of the total sea level rise in 1993, by 2014 this figure increased to about 25 percent. Credit: Pixabay.

These findings suggest that the world’s sea levels are rising faster than thought only a couple of years ago. If this accelerated trend continues, devastating consequences might ensue. The Intergovernmental Panel on Climate Change (IPCC), which is the UN science advisory body, estimates that by the end of the century sea levels could rise by 60 to 90 centimeters (24 to 35 inches). This very conservative projection, however, assumes the rate at which sea level rises stays constant.

Sea level rise due to global warming is a serious threat, on a collision course with large and growing coastal populations. Hundreds of millions of people live in low-lying deltas around the world and only a few feet extra in sea level is enough to force them out.

Global warming drives sea level rise by two major mechanisms:

  • by warming ocean water; as it warms, water expands, taking up more space

  • by melting land-based ice (glaciers and ice sheets), sending more water to our oceans.

According to a new study published in Nature Climate Change, accelerating losses of mass from Greenland and Antarctica are driving up the rate of sea level rise. The researchers fixed some loose ends in satellite altimetry data, which gauges heights on the Earth’s surface from space, using satellites. Until recently, the data showed little change in sea levels over the last two decades even when other measurements like in-situ clearly showed an increase in the levels.

“We corrected for a small but significant bias in the first decade of the satellite record,” co-author Xuebin Zhang, a professor at Qingdao National Laboratory of Marine Science and Technology in China’s Shandong Province, told AFP.

While thermal expansion accounted for almost half of added sea level rise in the early 1990s, two decades later that figure was only 30 percent. Instead, contributions from ice sheets and glaciers have increased from about half of the total rise in 1993 to around 70 per cent in 2014. Most of this sharp increase can be pinned on the melting of the Greenland ice sheet which now supplies 25 percent of total sea level increase compared with just five percent 20 years earlier. Greenland contains enough frozen water to lift oceans by about seven meters (23 feet).

Even if we cease dumping greenhouse gases into the atmosphere tomorrow, sea level rise that will continue because global warming is already locked-in and by some account triggered feedback loops are accelerating warming. For instance, despite the amount of CO2 released into the atmosphere has stabilized in the last five years, CO2 levels in the atmosphere are rising — and fast. As such, these findings must serve as a wake-up call for policymakers. The cost of non-action could be dramatic by the end of the century.

Guillemot chicks leap from their nest, risking life and limb, before they can even fly — and know we know why

The seemingly death-inviting behavior of young guillemots (also known as murres, Uria aalge) — who leap from their nests hundreds of meters above the sea guided by their fathers — has been shown to be an efficient survival strategy for the birds, explaining the bizzare behavior.

Image credits Dick Daniels / Wikimedia.

Before their wings grow long enough to offer sufficient lift for them, young guillemots jump from the nest into the sea, relying on their fathers to steer them away from the rocks below. Naturally, scientists have long wondered what drives these hatchlings to take the risky leap — there must be an advantage to the species, else the instinct would have been purged by selective evolution.

One of the leading theories was that the hatchlings have to leave the nest when they reach about one-quarter of their adult size because at that age they’re strong enough to defend themselves from predators but too big for the parents to keep feeding them. But chicks who didn’t want to brave the dangerous high seas would simply hop out of the nest and remain close to the colony. In a way, this leap is a leap of faith — the chicks risk a deadly jump hoping to feed (although food resources near the colony aren’t very plentiful) while still benefiting from the colony’s protection.

That theory, however, ran into a lot of problems when scientists from McGill and Memorial Universities in Canada and Aarhus and Lund Universities in Denmark and Sweden, tracked the behavior of guillemot fathers and their chicks for six weeks in colonies off the coast of Newfoundland and in Nunavut, Greenland.

World’s #1 Dad(s)

The murres’ rearing behavior is pretty uncommon among animals: where most species delegate the responsibility to the mother, in the guillemots’ case the chick is raised by both parents for about three weeks, after which the father takes over. He will spend the next 5 to 7 weeks at sea feeding and caring for the chick by himself. The mom spends this time at the colony copulating with other males in search for a suitor to replace her male if he dies at sea and doesn’t return the next year — another bit of promiscuity in the animal world.

 

“The Arctic summer is short”, says Kyle Elliott, who teaches in McGill University’s Department of Natural Resource Sciences. “The mother must produce an egg quickly. Murres have the highest flight costs of any animal, and the female works hard at the front end flying back-and-forth to the colony, leaving her exhausted by mid-summer.”

“Nonetheless, we were astonished to see how hard the father worked through late summer, spending virtually every daylight hour diving to feed the chick.”

The team noted that mortality rates among guillemot chicks at sea and those in the colony were very similar. Secondly, the chicks at sea grew almost two times faster than those still near the colony, as their fathers had to fly shorter distances to feed them.

“Once you know that there are both higher growth rates for the chicks at sea, and similar survival rates compared with life in the colony, it then makes sense to see this seemingly death-defying leap as a win-win strategy when it comes to survival,” says Elliott.

“We would never have been able to discover this without using the kind of state-of-the-art recorders that are now available and provide a glimpse into the life of murres on the high seas.”

They’re such committed dads, aren’t they?

The full paper “Variation in Growth Drives the Duration of Parental Care: A Test of Ydenberg’s Model” has been published in the journal The American Naturalist.

 

Some parts of Greenland really are green, but don't let the name fool you like the early Vikings. Credit: Flickr

Not too long ago, Greenland stayed ice-free for 280,000 years

Around 1.1 million years ago, the world’s largest island was largely devoid of ice. Its bedrock stayed bare for some 280,000 years, according to a new study, and the same could happen again.

Some parts of Greenland really are green, but don't let the name fool you like the early Vikings. Credit: Flickr

Some parts of Greenland really are green, but don’t let the name fool you like the early Vikings. Credit: Flickr

Some might say this isn’t surprising given the name Greenland, but that’s not entirely clear at all. There’s this myth that the island was almost entirely covered in vegetation and stripped of ice when the first Viking settlers arrived. But the legend has it their leader Erik the Red came up with this name to lure people into settling there by making it sound more attractive. He might have just been a ‘small lie’ because parts of Greenland’s coastline really is green. Today, there are many areas on the island where people farm and raise animals. However, largely, Greenland is anything but green.

It’s also possible that in the 10th century when the Norse arrived, Greenland may have been more hospitable than it is today. During that time, a brief period of local warming called the Medieval Climatic Anomaly raised temperatures a notch. This too is put into question by a 2015 study, which concludes, after studying cores from old glaciers, that the climate was already cold when the Norse arrived.

What the science says so far is that the Greenland ice sheet is between 400,000 and 800,000 years old. This ice sheet extends about 1.7 million square kilometers (656,000 square miles), covering 80%. In some places, this ice sheet is three kilometers thick.

The real Green Land

For what we knew so far, Greenland, which is three times larger than Texas, could have always been covered in ice, but this is not the case says Joerg Schaeffer, a paleoclimatologist with the Lamont-Doherty Earth Observatory, and a professor at the Department of Earth and Environmental Sciences at Columbia University.

Schaeffer and colleagues performed a first of its kind study — an isotopic analysis on the only rocky core ever extracted from the island. The core was drilled in 1993 and the mineral encased inside it can tell us not only the bedrock’s composition but also when and for how long it was exposed to ice.

“This rock is probably the most unique terrestrial rock sample ever,” Schaefer said. “It’s as precious as the moon rock that was retrieved in the 1970s.”

We had to wait until recently, however, for technology to catch up. Armed with modern, sensitive equipment for isotopic analysis, the researchers first dissolved the minerals in acid until these became atomized. Then, they compared the beryllium 10 and aluminum 26 isotopes ratios, which are only produced by cosmic rays interactions. If these are present, it means that layer of rock from the drilled core was directly exposed to sunlight, with no ice to block its path.

The analysis revealed that Greenland’s bedrock was ice-free for 280,000 years until 1.1 million years ago. During this time, Greenland’s ice cover would have been only 90 percent of what it is today, the study concludes.

“This means the Greenland ice sheet is really much less stable and more dynamic than we thought,” Schaefer said.

Studies such as this one are important for predicting the stability of Greenland’s ice sheet, second only to that in Antarctica with respect to the volume of water it traps. This year’s seasonal melt in Greenland was way above average, with the third highest surface mass loss of ice in 38 years of satellite observations. Greenland seems to be on track to gradually melt, reverting maybe to a situation seen a million years ago. When this happens, a huge volume of water will be displaced causing sea level rise.

“I would say that the leading hypothesis [now] is that not too much warming is required to remove much or most of Greenland’s ice to expose rock at GISP2,” study co-author Richard Alley told Gizmodo.

 

 

 

The stromalites trapped in layered rocks from Greenland. Credit: ALLEN NUTMAN

Oldest evidence of life on Earth found in 3.7-billion-year fossil

The stromalites trapped in layered rocks from Greenland. Credit: ALLEN NUTMAN

The stromatolites trapped in layered rocks from Greenland. Credit: ALLEN NUTMAN

Locked in Greenland rocks dated from 3.7 billion years ago, scientists discovered the oldest physical evidence of life on the planet. What the researchers found was not fossilized life, but rather telltale structures carved in the rock by bacteria called stromatolites, sort of like a footprint.

Pushing ancient life farther in time than ever before

If the findings are confirmed by other independent researchers, these stromatolites would be 220 million years older than the previous record-holder, also stromatolites but found in Western Australia. These structures are made by microbial communities which trap and bind sediment or attract carbonate from surrounding water. The algae or bacteria that build these thin layers can’t be found, but their presence can be marked for billion of years onward.

We don’t know which kind of bacteria or the type of organism, for that matter, that formed the stromatolites. What we know for sure is that these ancient organisms, perhaps the earliest we can infer so far, were water-based since it would be impossible for the sediments to form otherwise.

These were unearthed from the Isua supracrustal belt in southwest Greenland by a team of Australian and US researchers. The site is home to some of the oldest rocks ever, some extending up to 4.2 billion years.

Isua rocks are metamorphic — sedimentary rocks subjected to extreme temperature and pressure. Typically, these conditions deform the original rock so everyone was very surprised to find stromatolites etched inside them. At the same time, critics are concerned that the metamorphic conditions have altered the fossil too.

Yet, if what we’re seeing now is confirmed, the story of life on Earth might become a whole lot richer and interesting. Studies which backtracked the evolutionary lineage to its very origin suggest that life first surfaced some four billion years ago, or half a billion years after the Earth coalesced into what you’d call a planet. The Greenland rocks seem to support this hypothesis.

“This idea of the Earth as being bombarded by meteorites and, basically, volcanoes and [having] no water, has kind of evaporated so now we have a rather modern-looking planet with global oceans and some land going back several hundred million years before these fossils were found,” said Nick Lane, an evolutionary biochemist from University College, London, for The Guardian.

“This is really just another piece of evidence that suggests that the world was far more comfortable, if you like, for life as we know it on a global scale than you would perhaps read in even quite recent books,” he added.

The findings published in Nature could also aid scientists in their quest to discover signs of life on other planets, particularly on Mars. About the same time these Greenland layered rocks formed, our neighboring red planet was wet and warm — basically a habitable planet for all we know. As such, looking for stromatolites might be our best bet so far, especially since these ought to be far better preserved than on Earth since Mars lacks plate tectonics and hence isn’t subjected to the same destructive geological processes.

The Greenland ice sheet is losing some 270 billion tons of ice each year, a new study finds

A new study focusing on the Greenland Ice Sheet found that the rate of ice loss has accelerated over the past few years, confirming previous measurements. To put it into perspective, the sheet is now losing some 110 million Olympic-size swimming pools of water every year.

Image credits NASA Goddard Space Flight Center / Flickr.

One direct consequence of all the greenhouse gases we’re emitting into the atmosphere is melting ice. Doesn’t sound so dramatic — ice on my front lawn melts every spring, there’s ice-covered lakes and ice-bergs that sometimes melt and a little water never hurt anybody, right? For those things, yes. It’s a small quantity of ice, and it’s already floating on bodies of water so it won’t affect the volume of the world’s oceans if it melts.

But our planet has one huge deposit of water that doesn’t take part in the liquid’s natural cycle — ice sheets. When these melt, the water finds its way into the ocean and raises the sea level of the world’s oceans. So knowing how melting happens every year is important not only to help us quantify our activity’s effect on climate, but also because it helps us estimate how much sea levels rise.

However, you can’t simply hammer a tap into the ice and measure how much water flows out. What we can do is measure the volume of ice. This requires high-precision measurements of the ice sheets’ sizes over a long period of time to yield reliable results. In a new study, an international team reports the findings of one such high-precision measurement of the Greenland Ice Sheet, and their results confirm previous estimates of its rate of melting.

Malcolm McMillan from the Centre for Polar Observation and Modeling and his colleagues mapped the ice-sheet with incredibly high resolution (5 km distances,) by using data from the CryoSat 2 satellite. It relies on a technique called radar altimetry to measure terrain height, and with it the team was able to track the behavior of Greenland’s ice sheets with more precision than ever before.

In theory, if an ice sheet gains in altitude, it means that it’s also gaining in volume, so there’s more ice. A drop in altitude would correspond to a thinning of the ice caused by melting. But the processes that create the sheets are a little more complex — the Greenland sheets are thousands of meters thick, but the top layers are made up of snow and firn which gradually compress into solid ice. Accounting for the constitution of the sheet thus becomes very important in determining how much water gets trapped or released into the ocean.

After accounting for changes in density, surface roughness, and water content the authors found how much ice Greenland is losing, and how this melt varies by location and time. For example, 2012 saw a huge amount of ice loss compared to other years. The western side of the ice sheet is also melting much faster than the eastern side. The team found that a small part of the ice sheet (less than 1% of the sheet) is responsible for more than 10% of the mass loss.

Rate of mass change between January 2011 and December 2014 from CryoSat-2 radar altimetry. The color wheel indicates ice mass lost each year, with the radius scaled according to the magnitude of the total losses. The boundaries between the four sectors are shown in gray. Image provided by authors.

Rate of mass change between January 2011 and December 2014 from CryoSat-2 radar altimetry. The color wheel indicates ice mass lost each year, with the radius scaled according to the magnitude of the total losses. The boundaries between the four sectors are shown in gray.
Image credits Malcolm MacMillan et. al, 2016.

They estimate that between 2011 and 2014, some 270 gigatons of ice have melted away from Greenland — that’s enough water to fill 110 million Olympic swimming pools each year. This matches other independent measurements almost perfectly, helping to confirm the numbers.

“Using high resolution satellite data from ESA’s CryoSat-2 mission, we have produced a detailed and comprehensive picture of how Greenland has changed in recent years. In particular, we have been able to map the changing ice sheet in fine detail, and pinpoint where, and when, the greatest ice losses have occurred,” McMillan said in an interview for The Guardian.

The measurements allow scientists to calculate how much ice has been lost every year and determine the relationship between mean temperatures and melt — by looking at melt during the record summertime temperatures of 2012, for example. The variations in ice quantity show to what extent Greenland contributes to the sea level rise we’ve seen in recent years. And, thanks to their high resolution, researchers can also highlight which glaciers are experiencing the most melt.

The duration of this study was a relatively short 4 years. Hopefully, the team will continue their measurements in the following years, so we can get a better understanding of how sea levels will evolve in the future.

The full paper, titled “A high-resolution record of Greenland mass balance” has been published online in the journal Geophysical Research Letters.

Huge portion of Greenland starts to melt, surprises scientists

A massive portion of the Greenland ice sheet has started to melt, taking researchers by surprise. The vast region is experiencing a freakishly early spring thaw, with 12% of Greenland’s ice melting on Monday, according to the Danish Meteorological Institute.

“We had to check that our models were still working properly,”6 Peter Langen, climate scientist at DMI, told blog Polar Portal.

Left: Maps showing areas where melting took place on Monday (April 11th) and Tuesday (April 12th). Right: Average percentage of the total area of the Greenland ice sheet that melts over the course of a year, from 1990-2013 (gray) compared with 2016 (blue). Image: DMI

This is extremely worrying. Not only is a big part of Greenland melting, but it’s melting much sooner than it normally is. Thawing season normally starts in late May or June. The three earliest ever recorded meltings started in May 5, 2010, May 8, 1990, and May 8, 2006. This is almost a month earlier. Basically, these are hot days for July, let alone April.

“Even weather stations quite high up on the ice sheet observed very high temperatures on Monday”, said Robert Fausto, a scientist at GEUS who maintains PROMICE.dk melt data. “At KAN_U for example, a site at 1840 m above sea level, we observed a maximum temperature of 3.1°C. This would be a warm day in July, never mind April”. Other PROMICE stations in the network at lower levels had daily average temperatures between 5 and 10 °C. 

The good news is that because this happened so early in the year, there’s a good chance that the melting water will freeze again, but the bad news is that by doing so, it will suck heat energy from the depths, which means that the entire system will be left more vulnerable in the face of future thawings. All in all, it seems like Greenland is set for another hot year.

 

 

What polar inhabitants want from a climate deal

While the climate talks in Paris are carrying on in full force, it’s important to keep in mind that most of climate change isn’t actually affecting the ones causing it. The polar regions, the south Pacific and small islands are the ones suffering the most. The governments of Nunavut (Canada) and Greenland (Denmark) and the Inuit Circumpolar Council (ICC) released a joint statement on climate change at the COP21 climate meeting in Paris today.

“We are here to deliver an urgent message on behalf of the people of the North. When it comes to climate change, Nunavut is one of the most vulnerable areas on earth,” said Nunavut Premier, Peter Taptuna. We are deeply concerned about the impacts of climate change on sea ice and our way of life. We therefore stand before you today, with the Government of Greenland and the Inuit Circumpolar Council, asking the United Nations to reach an agreement that accounts for the impacts of climate change on the Arctic.”

Nunavut is the largest but least populous district of Canada, with a population of about 31.000 people. Greenland has almost twice as more people, and it also has significant scientific importance, with a permanent HQ set up there.

“Greenland has an important responsibility in promoting international climate research. Greenlandic climate research combines international cutting-edge research with an Arctic human dimension. Our joint Inuit voice and our traditional know-how from across the Arctic should be heard and included in international policy-making. Most importantly, Arctic indigenous peoples have to be ensured an equal access to the right to development. Indigenous peoples’ rights and interests must be included in the COP21 outcome document.” – Greenland Minister, Vittus Qujaukitsoq

Climate change isn’t uniform throughout the globe, and some areas are suffering more than others. The Arctic is already experiencing acute impacts related to climate change, with significant rise in temperatures, permafrost thaw, loss of glacier ice and disruptions to wildlife. Furthermore, the areas in the Arctic are virtually without fault, considering the scale of global emissions. With this in mind, they proposed a climate deal that:

 

  • Strongly reconfirms the principle of a common but differentiated responsibility in tackling climate change.
  • Takes enhanced measures to stabilize global greenhouse gas (GHG) concentrations below ~450 parts per million by volume to make certain global temperature increases will remain between 1.5°C and 2°C.
  • Recognizes and protects the rights of Indigenous peoples and the values, interests, culture and traditions of the peoples of the Arctic.
  • Ensures equal access to the right to development, also for the peoples of the Arctic.
  • Acknowledges the extremely high cost of living in the Arctic and does not impose further financial burden to Arctic regions.
  • Advocates the development and expansion of energy solutions that reduce greenhouse gas emissions, also for areas like the Arctic.
  • Ensures that Inuit food security is protected.
  • Promotes the need for adaptation action in areas that are disproportionately affected by climate change, such as the Arctic, and for sustainable funding to support such initiatives.
  • Recognizes the importance of indigenous knowledge, its significant contribution to our understanding of climate change, and acknowledges its value being on par with scientific data.

While some of the points are definitely debatable, ensuring the people’s food security and supporting their sustainable development should definitely be a priority, especially considering how disproportionately they are affected.

 

 

Scientists unravel mystery of Greenland lakes: they’re sinking

Geoscientists have finally unraveled one of Greenland’s long-standing mysteries: how billions of gallons of water can drain in a matter of hours. They believe that this might also help us better understand how sea levels will rise in the future.

Greenland’s superglacial lakes. Image via Washington University.

Every summer, Greenland’s ice starts to melt and “pockets” of water start to form – I use the quotes because these pockets can reach enormous sizes. They are basically large lakes, superglacial lakes (because they form on ice). In 2006, Greenland’s North Lake, a 2.2 square-mile (5.6 square kilometers) “pocket” lost almost 12 billion gallons of water in less than two hours, and researchers couldn’t figure out where all the water went. This is not a singular case; similar drains have been observed several times across Greenland’s surface. Now researchers at MIT, Woods Hole Oceanographic Institution (WHOI) claim they’ve finally cracked that mystery.

“We’ve found a mechanism that demystifies what’s happening.” The lead study goes on to say, “We know that the ice sheet will continue to increase its contribution to sea level rise over the coming years. The implications of this study show us more of how these processes will play out.”

It was clear that the water has to seep through some fractures in the ice, but it was not known what causes these fractures. Ironically, it’s actually the water. In this new study used GPS technology and found that the hydro-fractures form from tension-related stress caused by movements of the ice sheet. These movements are, in turn, triggered by the trickling meltwater.When summer comes, meltwater drains to the bed from the ice surface through crevasses or moulins and it causes the area within and around the basin to “jack up”; it also decreases the surface area of the ice-sheet bed that’s in contact with the underlying bedrock, acting like a lubricant for the entire lakebed.

“We found that before we get the main expression of the lake drainage, there is a period of time (about six to 12 hours) where uplift and slip increase,” said Laura Stevens, a glaciology doctoral candidate with the Massachusetts Institute of Technology/Woods Hole Oceanographic Institution (MIT-WHOI) Joint Program. “That motion is enough to take the surface of the ice sheet and put portions of it in high tension that allows cracks to start forming.”

While most of Greenland’s superglacial lakes drain slowly, some 13% of them drain quickly, vanishing in less a day.

“The images would show the lake there one day, and gone the next day,” said first author of the new study, Stevens adds. “So we’ve known for the last 10 to 15 years that the water could disappear quickly.”

A supraglacial lake on the western margin of the Greenland Ice Sheet.
Credit: Laura A. Stevens

There is more to this study than just understanding the glacial dynamics that enable fast drainage – this could have implications for global sea levels.

“It is critical to understand how and why these lakes drain in order to predict how much mass the ice sheet will contribute to sea-level rise in our warming climate,” Stevens says. “We find that while lakes are forming inland, they probably won’t drain by this … mechanism. The inland lakes will more likely drain their water via surface stream runoff, which transfers the water to the bed in more coastal areas of the ice sheet. So, while we see inland ice beginning to speed up as more melt happens inland, the draining of inland lakes likely won’t exacerbate the situation.”

While there are no definite results at the moment, it seems that this process won’t actually affect sea-level rise, but it could enable researchers to develop better climate models.

Richard Alley, a professor of geosciences at Penn State University who was not involved in the research thinks this may be especially useful.

“For Greenland, the worst possible case won’t be quite as bad as people might have thought,” says Alley, who was not involved in the research. “I think that the big contribution here is to other scientists in the field; we will use these interesting and useful results to improve models and projections, and to guide further research.”

Meltwater on the Greenland ice sheet carved this canyon. Credit: IAN JOUGHIN

New subglacial lakes discovered in Greenland accelerating melting

Using satellite imagery, scientists have discovered two new subglacial lakes under Greenland’s ice sheet bringing the total number to four. The discovery is not well met, however. These lakes are already drained, signaling that climate change is making its way beneath the Greenland ice sheet. The discovery suggests subglacial lakes could increase the sensitivity of ice to climatic change, further accelerating ice melt.

Lakes beneath the thick Greenland ice

Meltwater on the Greenland ice sheet carved this canyon.  Credit: IAN JOUGHIN

Meltwater on the Greenland ice sheet carved this canyon. Credit: IAN JOUGHIN

Scientists were intrigued by an unusual summer melting season in 2011. Then,  billions of gallons of water had flushed some 30 miles (50 kilometers) to the sea, leaving behind sunken craters in the surface of the ice above the lakes.  Michael Bevis, of the School of Earth Sciences at Ohio State University in Columbus, and colleagues used satellite imagery to inspect the anomaly and found a lake corresponded for each of the two huge craters, nested beneath the huge Greenland ice sheet.

[ALSO SEE] Frozen underworld discovered under Greenland ice sheet

Greenland’s ice sheet is the second largest ice sheet in the world after Antarctica and it covers almost 80 percent of the island. The island has 2.8 million cubic kilometers volume of ice and at some spots the ice is about 3 kilometers thick.

The first lake had been there for around 40 years, and was filled with 6.7 billions of gallons of water or enough to fill 10,000 Olympic swimming pools.  However, based on more recent satellite images, the lake seems to have dried up, around 4 years ago, in 2011.  The crater left, stretches on a distance of 1.2 miles all around and across, and has a depth of 70 metres, the height of a ten story building.

The second lake  in northeastern Greenland has filled and drained twice since its first blowout in 2011. Since it’s  230 feet (70 meters) deep, this tells us quite a bit about the state of warming and water melting in the region. The water itself is meltwater from the ice sheet’s surface, trickling downward through cracks in the ice. But this repeated depletion and refilling of the lake can only mean that there’s of excess heat affecting the ice sheet.

“This is a new mechanism for getting heat from the top of the ice cap to the bottom of the ice cap, and I think it’s likely that we’ll see it happening at other places in the future,” said Michael Willis, lead author of the Nature study and a glaciologist at Cornell University and the University of North Carolina at Chapel Hill.

“If enough water is pouring down into the Greenland Ice Sheet for us to see the same subglacial lake empty and refill itself over and over, then there must be so much latent heat being released under the ice that we’d have to expect it to change the large-scale behavior of the ice sheet,” said Michael Bevis, a geophysicist at Ohio State University and co-author of the Nature study.

A lake under the ice in northeast Greenland that emptied and is now refilling with surface water that drains downward through cracks. (Image: Cornell University)

A lake under the ice in northeast Greenland that emptied and is now refilling with surface water that drains downward through cracks. (Image: Cornell University)

The two lakes are quite important because they tell us how the ice sheet’s  Basal ice layer performs. The basal layer is the part of the glacier in which the nature of the ice is directly affected by proximity to the glacier bed.  The meltwater, the results of rising global temperatures, essentially lubricates the basal layer and makes it more likely to slide out to sea, researchers said.

Global warming has already affected Greenland considerably. Between 2003 and 2012, the northeast region of Greenland’s ice sheet receded nearly 20 kilometers. Yet because of the  amount of water draining into the subglacial lakes the ice sheet will only get softer due to the heat. This can only mean more ice lost – far more than previously estimated.

In Antarctica, there are 400 such lakes entombed beneath its thick ice, but in Greenland scientists have only discovered four, including the two reported now. Researchers believe there may be more lakes, but never as many as those in Antarctica. The steep topology of Greenland simply doesn’t allow it, as water is quickly led out to sea.

“I think there will be more lakes, but I think that we won’t find that these lakes are a major player in the behavior of the large-scale behavior of the ice sheet,” said Garry Clarke, a glaciologist at the University of British Columbia who was not involved in the two studies.

Over the 19 years studied, the Greenland ice sheet lost 2.7 trillion metric tons of ice — about the same mass as 8 million Empire State Buildings. The Antarctic ice sheet also shrank, by about 1.3 trillion metric tons. That is roughly the equivalent of 4 million Empire State Buildings.

The findings were reported in the journal Nature.

Frozen underworld discovered beneath Greenland Ice sheet

The former popular landscape was an expanse of warped shapes, out of which some were as tall as a Manhattan skyscraper, and it was discovered by an ice-penetration radar loaded aboard NASA survey flights.

According to the scientists who made the discovery, this could deepen the level of understanding concerning the way in which the ice sheets of Greenland and Antarctica respond to climate change. Until recently, the scientific community believed that the the shapes they discerned beneath the ice sheet were nothing else but mountain ranges, according to the specialists studying the Greenland ice sheet for evidence of change under the circumstances of global warming.

Everything was just flat, parallel lines. This is how the ice is supposed to be. But here it is breaking all the rules. You get these crazy, folded, distorted, overtuned, undulating things at the bottom of the ice, and they are the size of skyscrapers’, declared Kirsty Tinto, geophysicist at Lamont-Doherty.

It was the new technologically advanced new gravity-sensing and radar operating from NASA’s airborne surveys of the ice over the last 20 years how the scientists got to the conclusion that the formations they had identified were not rock, but ice.

The melting and subsequent re-freezing of water at the bottom of the ice sheet is what caused the formations, as stated by the scientists – who were really surprised by their results. It’s even more surprising that these new-found structures, some of them measuring up to 1 meter thick, cover approximately 10 per cent of the surveyed areas of Northern Greenland.

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Around Petermann glacier in north-western Greenland there were found circa a dozen formations, which has caused fast changes, given that two years ago they calved an iceberg twice the size of Manhattan – but the melting and re-freezing at the bottom of the ice has been happening for thousands of thousands of years, according to the scientists. While the scientists were informed of such a process, what they didn’t know until now was that the melt-water was re-freezing into more complex formations.

The melt-water is a result of the glacier warming under its own weight, and it freezes and grows up into the forms from around its base.

We see more of these features where the ice sheet starts to go fast. We think the refreezing process uplifts, distorts and warms the ice above, making it softer and easier to flow,’ declared Robin Bell, lead author of the study and geophysicist at Columbia University’s Lamont Doherty Earth Observatory.

The process appears to accelerate the flow of glaciers, according to Bell, but Tinto said that further research was needed in order to prove this hypothesis.

If we want to understand how ice is going to respond to climate change, we have to understand its fundamental dynamic. It is not just that you are melting the surface and the surface is just running into the sea. There is a complicated and quite beautiful system running through the ice and you have to understand it top to bottom to understand what it is doing”, said Tinto.

Mega canyon discovered under Greenland ice sheet

Geophysical data from Greenland have revealed the existence of a canyon comparable in size with the Grand Canyon beneath the ice sheet.

The canyon has the characteristics of a winding river channel and is over 750 km long and it is often as deep as 800 m. This immense feature is thought to predate humanity – it came to be several million years before the Antarctic ice sheet was developed.

“One might assume that the landscape of the Earth has been fully explored and mapped,” said Jonathan Bamber, professor of physical geography at the University of Bristol in the United Kingdom, and lead author of the study. “Our research shows there’s still a lot left to discover.”

Scientists used thousands of kilometers of airborne radar data collected by NASA and researchers from the United Kingdom and Germany over several decades, and managed to puzzle together the main characteristics of the Greenland canyon. They found that the geologic feature starts from almost the center of the island and ends beneath the Petermann Glacier fjord in northern Greenland.

At certain wavelengths, radar waves can travel through the ice, but bounce off the solid rock underneath. This enables us to map the depth of the canyon – the longer it takes for the wave to return, the deeper the canyon is.

“Two things helped lead to this discovery,” said Michael Studinger, IceBridge project scientist at NASA’s Goddard Space Flight Center in Greenbelt, Md. “It was the enormous amount of data collected by IceBridge and the work of combining it with other datasets into a Greenland-wide compilation of all existing data that makes this feature appear in front of our eyes.”

Geologists believe the canyon plays an important role in transporting sub-glacial meltwater from the interior of Greenland to the edge of the ice sheet into the ocean. Existing evidence (this canyon included) suggests that before the ice sheet existed, some 4 million years ago, the canyon hosted an extensive river system which flowed from the interior to the coast.

“It is quite remarkable that a channel the size of the Grand Canyon is discovered in the 21st century below the Greenland ice sheet,” said Studinger. “It shows how little we still know about the bedrock below large continental ice sheets.”

For more information about IceBridge, the operation which led to this discovery, check out their website. The IceBridge campaign will return to Greenland in March 2014 to gather more data and develop a more conclusive picture of the subglacial features in Greenland.

Via NASA.

A core extracted from the Greenland ice sheet shows that during the Eemian period 130,000 to 115,000 thousand years ago the climate in Greenland was around 8 degrees C. (14.4 F.) warmer than today. The inset graph shows the change in surface height and temperature over time.

Greenland ice core reveals it withstood warmer climate and warns of the future

A newly published massive study, where some 133 scientists collaborated, revealed that during our planet’s last warm period between ice ages the Greenland ice sheet was still fine and sturdy, despite it was a lot shorter than it is today and caused an increase of a few feet in world sea levels. The authors involved in the paper warn that carbon dioxide levels are on par with current trends and if things continue to remain as now in terms of greenhouse gas emissions, then Greenland might irreversible dump its fair share of ice in the near future.

The four year long study was a veritable challenge for the international team of researchers, who analyzed ice core samples from the Greenland ice sheet, some 1.5 miles long. These samples served as time capsules, allowing the scientist to backtrack Earths’ climate far into the past, offering highly accurate and valuable data concerning temperature, ice sheet size and even atmospheric conditions. A certain heavy oxygen isotope, O18, came particularly in handy.

A core extracted from the Greenland ice sheet shows that during the Eemian period 130,000 to 115,000 thousand years ago the climate in Greenland was around 8 degrees C. (14.4 F.) warmer than today. The inset graph shows the change in surface height and temperature over time.

A core extracted from the Greenland ice sheet shows that during the Eemian period 130,000 to 115,000 thousand years ago the climate in Greenland was around 8 degrees C. (14.4 F.) warmer than today. The inset graph shows the change in surface height and temperature over time. (c) Niehls Bohr Institute

What interested the scientists most was the Eemian period, around 115 to 130 thousand years ago or better known as Earth’s last (very warm) interval between ice ages. Apparently during this time the region was 8 degrees Celsius warmer; that’s much warmer than it’s forecast to get in the coming decades. Apparently the ice sheet in Greenland withstood these high temperatures for 6,000 years, not without shaking some ice though.

In the Eemian the world’s oceans were four to eight meters higher than today, however the ice sheet in northwest Greenland was only a few hundred meters lower than the current level. This means Greenland ice sheet had a far less contribution to the global sea rise than previously thought, prompting scientists to direct their attention towards Antarctica which has always been the hardest environment to study.

Also, in a remarkable find scientists estimated that between 122,000 and 115,000 years ago, Greenland’s surface elevation had dropped to about 425 feet below the present level as a result of melting. The scientists however paint a gloom picture of the future and lament the current poor state of awareness regarding the impending peril our grandchildren will face at the cost of present day comfort.

“Unfortunately, we have reached a point where there is so much carbon dioxide in the atmosphere it’s going to be difficult for us to further limit our impact on the planet,” co-author Jim White, the director of the University of Colorado, Boulder’s Institute of Arctic and Alpine Research, said in a separate statement. “Our kids and grandkids are definitely going to look back and shake their heads at the inaction of this country’s generation. We are burning the lion’s share of oil and natural gas to benefit our lifestyle, and punting the responsibility for it.”

“We were quite shocked by the warm surface temperatures observed at the NEEM ice camp in July 2012,” said Dahl-Jensen. “It was raining at the top of the Greenland ice sheet, and just as during the Eemian period, meltwater formed subsurface ice layers. While this was an extreme event, the present warming over Greenland makes surface melt more likely, and the predicted warming over Greenland in the next 50-100 years will very likely be so strong that we will potentially have Eemian-like climate conditions.”

Findings were documented in a report published in the latest edition of the journal Nature.

Antactic ice sheet retreat

Antarctic rift the size of the Grand Canyon speeds ice sheet melting

Antactic ice sheet retreat

Scientists from Britain have found a remote ice rift valley, up to one mile deep, under the ice in Antarctica. The rift is similar in size and depth to the Grand Canyon and because it is direct contact with the warming ocean, it’s been found that it has a significant contribution to the unusual ice sheet melting of West Antarctica.

The rift lies beneath the Ferrigno Ice Stream on a stretch of coast so remote that it has only been visited once previously in 1961.

“Over the last 20 years we have used satellites to monitor ice losses from Antarctica, and we have witnessed consistent and substantial ice losses from around much of its coastline.”

For some of the glaciers, including Ferrigno Ice Stream, the losses are especially pronounced, and, to understand why, we needed to acquire data about conditions beneath the ice surface,” said Glaciologist and lead author, Dr Robert Bingham.

The ice sheet in West Antarctic is losing ice at a faster rate than any other part of the continent and some glaciers are receding annually by over one metre. Actually, it’s been found that West Antarctica’s thinning ice adds almost 10% to global rises in sea levels. You can imagine this didn’t went unnoticed, so scientists decided to closely investigate the area.

Using a special tower radar mounted on-top of a snowmobile, researchers were able to survey the area through which they traversed, roughly 1,500 miles.

“What we found is that lying beneath the ice there is a large valley, parts of which are approximately a mile deeper than the surrounding landscape,” said Dr Bingham.

“If you stripped away all of the ice here today, you’d see a feature every bit as dramatic as the huge rift valleys you see in Africa and in size as significant as the [US] Grand Canyon.

“This is at odds with the flat ice surface that we were driving across – without these measurements we would never have known it was there.”

After analyzing the valley geometry and correlating the warm ocean with which it is linked, the scientists found that it matches satellite ice thinning data. In the paper, the scientists claim that the Ferrigno Rift is part of a massive rift system that is little understood.

The study is part of the British Antarctic Survey’s Icesheets Programme that investigates how ice sheets change and what effect they have on the rest of the earth, including rises in sea levels. It’s thought that were the entire ice sheets of Antarctica and Greenland to melt, which are 4km thick, sea levels globally would rise by several metres.

The findings were reported in the journal Nature.

NASA satellite images showed the extent of surface melt on Greenland's ice sheet on July 8, on the left, and July 12, on the right. (c) NASA

Greenland’s entire ice sheet experiencing melting – unprecedented event in 30 years

NASA satellite images showed the extent of surface melt on Greenland's ice sheet on July 8, on the left, and July 12, on the right. (c) NASA

NASA satellite images showed the extent of surface melt on Greenland’s ice sheet on July 8, on the left, and July 12, on the right. (c) NASA

During just four days, from July 8 to July 12, Greenland‘s total ice sheet surface subjected to melting rose from 40% to a whooping 97%. Basically the whole Greenland ice sheet was melting during this time frame. According to NASA, a situation similar to this mid-July phenomenon hasn’t been ever recorded in the three decades of satellite observations.

Now, melting of the ice sheet is always common during the summer, before refreezing during winter or running off into the ocean. However, this most recent phenomenon which virtually had Greenland’s entire surface subjected to melting is so peculiar, that not even scientists aren’t yet sure what to make of it. “[It] makes you sit up and ask what’s happening,” said NASA’s chief scientist Waleed Abdalati for TIME. Even Greenland’s coldest and highest place, Summit station, showed melting.

“You literally had this wave of warm air wash over the Greenland ice sheet and melt it,” NASA ice scientist Tom Wagner said Tuesday.

So far NASA scientists aren’t sure if this is a natural anomaly or somehow triggered by human-induced global warming. What they do do know for certain is that the edges of Greenland’s ice sheets have already been constantly thinning during the past decade due to climate change. Most likely, an unusually strong warm air, or heat dome, which had engulfed Greenland since May before dissipating on July 16, caused the event.

Just recently, we reported that an iceberg two times the size of Manhattan broke off from Greenland’s Petermann Glacier. In 2010 Greenland lifted by as much as three quarters of an inch after glaciers and ice sheets above its surface melted, amounting to a total of 100bn tones of melted ice.

Satellite photo of the Petermann glacier before the giant iceberg broke off the ice sheet. Notice a significant crack shaped like a circle arc. (c) NASA

Iceberg twice the size of Manhattan breaks off Greenland glacier

Researchers at the University of Delaware and the Canadian Ice Service recently reported that an ice island, whose surface is twice that of Manhattan, broke off from Greenland’s Petermann Glacier, one of the two largest glaciers left in Greenland connecting the great Greenland ice sheet with the ocean via a floating ice shelf.

The 46-square-mile giant iceberg broke off from the glacier on Monday, and has since started its journey towards the open ocean.The on-site discovery was confirmed with satellite imaging from the Moderate Resolution Imaging Spectroradiometer aboard NASA’s Terra and Aqua satellites.

Satellite photo of the Petermann glacier before the giant iceberg broke off the ice sheet. Notice a significant crack shaped like a circle arc. (c) NASA

Satellite photo of the Petermann glacier before the giant iceberg broke off the ice sheet. Notice a significant crack shaped like a circle arc. (c) NASA

An hour and a half after the previous image was taken, this photo shows the iceberg has begun to move toward the open ocean. (c) NASA

An hour and a half after the previous image was taken, this photo shows the iceberg has begun to move toward the open ocean. (c) NASA

Although the new iceberg is admitedly large, it rather pales in comparison to its predecessor from 2010, when a chuck of ice 97-square-mile chunk of ice broke off from the Petermann Glacier – the largest iceberg recorded in the Arctic since 1962. Last year, on the other side of the world, an iceberg the size of New York City broke off from the Antarctic ice sheet – 340-square-miles in surface.

Greenland ice sheet is melting and shrinking

“While the size is not as spectacular as it was in 2010, the fact that it follows so closely to the 2010 event brings the glacier’s terminus to a location where it has not been for at least 150 years,” says Andreas Muenchow, associate professor of physical ocean science and engineering in UD’s College of Earth, Ocean, and Environment.

“The Greenland ice sheet as a whole is shrinking, melting and reducing in size as the result of globally changing air and ocean temperatures and associated changes in circulation patterns in both the ocean and atmosphere,” he notes.

Muenchow points out that the air around northern Greenland and Ellesmere Island has warmed by about 0.11 +/- 0.025 degrees Celsius per year since 1987. This means Northern Greenland and Canada have been warming five times faster than the average global temperature, according to the scientist.

“Northwest Greenland and northeast Canada are warming more than five times faster than the rest of the world,” Muenchow says, “but the observed warming is not proof that the diminishing ice shelf is caused by this, because air temperatures have little effect on this glacier; ocean temperatures do, and our ocean temperature time series are only five to eight years long — too short to establish a robust warming signal.”

This is not an isolated incident. Many of glaciers in southern Greenland have been melting at an unusual rapid pace. If it continues, and more of the Petermann is lost, the melting would push up sea levels – the ice lost so far was already floating, so the breaks don’t add to global sea levels.

The new iceberg is expected to follow in the footsteps of the previous 2010 giant glacier, breaking apart into smaller icebergs as it moves away north, then west, before reaching the shores of Newfoundland.

Source: University of Delaware via Our Amazing Planet

The Jorge Montt glacier in Southern Patagonian Ice Field has witnessed a significant retreat in the past year alone. (c) AFP

Glacier in Chile retreats half a mile in a year

According to Chile’s Centre for Scientific Studies (CECs) it seems like an array of glaciers located in the country’s south have shrunk extensively recently. One such glacier, the Jorge Montt, was documented for a whole year by researchers who observed that its rate of shrinkage is the largest in the country, with snout retreating a whopping 1 kilometer during the past year alone.

The glacier which is  part of the 5,020 square mile Southern Patagonian Ice Field, the third largest frozen land mass after Antarctica and Greenland, was documented by researchers with the help of 1,445 time-lapse photos, which were pieced together to form a rather grim view. The video was striking even for the researchers, as Andres Rivera, lead glaciologist, confesses he couldn’t picture the scale of the ice shrinkage until two cameras with solar panels to charge the batteries were programmed to shoot four frames a day.

“It was more or less clear that this was one of those retreating most quickly. But we didn’t expect in the year of working with these cameras that it would retreat a kilometer more. That was a surprise,” Rivera said. “This glacier is filled with surprises for us.”

Rivera claims global warming is a big factor to blame for this retreat, however due to the fact that the glacier is placed in the waters of a deep fjord, it’s melting is facilitated. The researchers believe that based on a map from 1898, this glacier has retreated roughly 12 miles (19.5 kilometers) since then.

“Such glaciers typically do retreat in response to warming. But the speed of the retreat is controlled by the ability of icebergs to break off in the fjord, not by the rate of warming,” said Richard Alley, a prominent glaciologist at Penn State University.

A recent study conducted by British and Swedish scientists who analyzed about 350 glaciers in Patagonia, concluded that all but two of the glaciers have receded significantly since the late 1800s and have been shrinking at a faster rate during the past three decades.

The time-lapse video of the Jorge Montt glacier massive retreat can be seen below.

 

The study was published in a recent edition of the journal Nature Geoscience.