Tag Archives: greenland

Greenland expedition discovers world’s northernmost island by accident

A little luck can go a long way. In Greenland, a group of scientists have just discovered a new island by luck, which they believe is the world’s northernmost point of land. At just 30 meters across, it’s quite the unusual island.

Image credit: Flickr / University of Copenhagen.

Morten Rasch, scientific leader of the Arctic Station in Greenland, flew with a group of colleagues to collect samples of what they thought was Oodaaq Island, which has been known since 1978 as the most northerly point of land on Earth. But they are actually mistaken, something they realized after posting photos and coordinates on social media.   

Rasch said a group of American island hunters, adventurers that explore unknown islands as a hobby, “went crazy” and said the coordinates posted by Rasch couldn’t be true. This prompted the team to contact an expert at the Technical University of Denmark, who realized the GPS was mistaken and that they weren’t on Oodaaq. 

“In fact, we had just discovered a new island further north, a discovery that ever so slightly expands the Kingdom,” Rasch said in a statement. They confirmed this by a GPS on the helicoper that was being used by the group to reach the island. They were actually 800 meters (2,625 feet) further north than what they had initially calculated. 

An unexpected discovery

Rasch told BBC that they wanted to visit Oodaaq Island to look for new species adapted to the extreme weather Greenland is known for. He said the discovery of the new island “isn’t a big deal” but considered somehow funny “to be among those six people ever on earth who have had muddy boots at the most northerly point in the world.”

The island is formed by small mounds of seabed mud and moraine, the soil and rock left behind by glaciers, Rasch said. It could have emerged due to a major storm that scraped the seabed materials together until the island was formed. Still, it’s unclear how permanent this expansion of Greenland (a territory controlled by Denmark) will be.

While it doesn’t have a name yet, the researchers hope to name the island Qeqertaq Avannarleq, which means “the northernmost island” in Greenlandic. Similar expeditions in recent decades have looked for the world’s northernmost island, mainly from US researchers. The latest discovery was in 2007 by Dennis Schmitt, who found a similar island in the area.

The island was exposed by shifting packs of ice, but the researchers believe that its appearance wasn’t a direct consequence of global warming – which has been reducing Greenland’s ice sheet steadily for the past few decades. In fact, Greenland is mostly covered by ice, which goes on for 1.7 million square kilometers (650,000 squared miles). This is three times the size of Texas.

The ice that melts away in Greenland, mainly due to human-caused climate change, flows was water into the ocean and adds to the sea level rise. Over the last decade, global sea level has risen at about 1.5 inches (four millimeters) per decade, according to the most recent report of the Intergovernmental Panel on Climate Change (IPCC). 

Rain falls on Greenland’s snowy summit for the first time on record

Precipitation at the summit of Greenland, about three kilometers above the sea level, fell as rain and not as snow for the first time since record-keeping began in 1950. Seven billion tons of water pelted the ice sheet for several hours, fueled by warm air. Temperatures at the summit rose above freezing for the third time in a decade, signaling severe trouble for Greenland.

Image credit: Flickr / David Stanley

It was the heaviest rainfall on the ice sheet since 1950, according to the National Snow and Ice Data Center, and the amount of ice mass lost on Sunday was seven times higher than the daily average for this time of the year. Ted Scambos, University of Colorado researcher, told CNN this is evidence that Greenland is warming rapidly.

“What is going on is not simply a warm decade or two in a wandering climate pattern. This is unprecedented. We are crossing thresholds not seen in millennia, and frankly this is not going to change until we adjust what we’re doing to the air,” Scambos said.

The rain fell from the southeast coast of Greenland up to the National Science Foundation’s Summit Station, where scientists observe Arctic weather and changes in the ice. The station is located at the highest point on the Greenland ice sheet. Now, because of the heavy rain event, researchers there think operations will have to change. 

“It means that we need to consider weather events that we have not had to deal with before in the history of our operations there,” Jennifer Mercer, program officer at the Science Foundation, told CNN. “Increasing weather events including melting, high winds, and now rain, over the last 10 years have occurred outside the range of what is considered normal.”

The rain will have a lasting effect on the properties of the snow, Mercer said, leaving a crust of ice behind that will absorb more energy from the sun until it gets buried by snow. This layer will also be a barrier that prevents the draining of meltwater, which will then flood the surface of the ice sheet and initiate runoff at higher elevations, Scambos said. 

This is far from being the first unusual phenomenon seen by the researchers. Two years ago, a polar bear made it to the summit station, which was very unusual as bears live in coastal regions where they can find food. The bear trekked for several hundred kilometers inland across the ice sheet. Mercer said that in the last five years three bears have been seen on the ice sheet.

A warming trend

Most of Greenland is currently covered by the Greenland Ice Sheet, which spans 656,000 square miles (1.7 million square kilometers) – three times the size of Texas, according to the National Snow and Ice Data Center (NSIDC).  It’s the second-largest in the world after the Antarctic one. Together, the two of them contain 99% of the freshwater ice on Earth. 

Ice that melts away in Greenland can flow as water into the ocean, where it adds to the ongoing increase in global sea level caused by human-induced climate change. Global sea level has risen about eight to nine inches (21 to 24 centimeters) since 1880. A third of that has happened in just the last two and a half decades, studies have shown. 

If all of Greenland’s ice were to melt, the seas would rise by about 24 feet (7.3 meters), according to a 2019 report by NOAA. This would be enough to flood most coastal cities around the world. While this won’t happen overnight, Greenland’s ice sheet is already melting now six times faster than it was in the 1980s, studies showed — and if last week is any indication, we’re up for a wild ride.

Climate experts from the United Nations Intergovernmental Panel on Climate Change (IPCC) published a landmark report earlier this month, warning that Earth could reach the threshold of 1.5ºC (2.7 degrees Fahrenheit) of warning due to climate change within the next 20 years. This would make extreme weather events much more common.

Greenland heatwave triggers melting — enough to cover Florida with 2 inches of water

A group of Danish researchers found that the Greenland ice sheet experienced a “massive melting event” last week during a heatwave that brought temperatures more than 20 degrees Celsius above seasonal norms. The ice sheet has melted by about eight billion tons a day, which is about twice the normal average rate seen during summer, they found.

Image credit: Flickr / Steve Weston

Most of Greenland is currently covered by the Greenland Ice Sheet, which spans 656,000 square miles (1.7 million square kilometers) – three times the size of Texas, according to the National Snow and Ice Data Center (NSIDC).  It’s the second-largest in the world after the Antarctic one. Together, the two of them contain 99% of the freshwater ice on Earth. 

Ice that melts away in Greenland can flow as water into the ocean, where it adds to the ongoing increase in global sea level caused by human-induced climate change. Global sea level has risen about eight to nine inches (21 to 24 centimeters) since 1880. A third of that has happened in just the last two and a half decades, studies have shown. 

If all of Greenland’s ice were to melt, the seas would rise by about 24 feet (7.3 meters), according to a 2019 report by NOAA. This would be enough to flood most coastal cities around the world. While this won’t happen overnight, Greenland’s ice sheet is already melting now six times faster than it was in the 1980s, studies showed — and if last week is any indication, we’re up for a wild ride.

A record heat wave 

The Danish researchers shared their results on the Polar Portal website, showing that the ice sheet lost 8.5 billion tons of surface mass last Tuesday and a further 8.4 billion tons on Thursday. The scale is so large that the losses on Tuesday created enough meltwater to drown the entire US state of Florida in two inches (or five centimeters) of water. 

“It’s a very high level of melting and it will probably change the face of Greenland, because it will be a very strong driver for an acceleration of future melting, and therefore sea-level rise,” Marco Tedesco, a glacier expert at Columbia University, told The Guardian. “The snow is like a protective blanket, once that’s gone you get locked into faster melting.”

Tedesco said the higher-than-usual temperatures in Greenland were caused by a patch of high pressure that is sucking and holding warmer air from further south “like a vacuum cleaner.” Once seasonal snow melts, the darker core ice is exposed, which then draws more heat, melts more, and adds to sea-level rise. These atmospheric events are getting longer and more frequent, he added. 

Greenland’s melting season normally lasts from June to August. According to the Danish researchers, the island has lost more than 100 billion tons of ice since the start of June this year. While this is less than in 2019, when a whopping 11 billion tons of ice were lost in a single day, the area affected is much larger this year. “There’s a ton of warm and moist air over the ice sheet,” glaciologist Brad Lipovsky told The Guardian.

A recent study from the University of Reading suggested that the Greenland Ice Sheet is inching in towards a dangerous threshold. In around 600 years, it will melt enough that the sheet won’t ever recover, no matter what we do, and sea levels remain permanently higher. This scenario assumes that current rates of melt remain constant.

The Greenland Ice Sheet is leaking mercury — likely natural, but still dangerous

As climate change keeps making our planet hotter and our glaciers melty, scientists report on an unforeseen issue: glacial meltwater from the Greenland Ice Sheet contains high levels of mercury, a toxic heavy metal. According to the report, these levels are comparable to those in rivers where factories dump their waste, creating a major threat to the seafood industry and people who enjoy its products.

Image via Pixabay.

It’s never a dull day with environmental woes. A study that began as an effort to analyze the quality of meltwater from the Greenland ice sheet, and how nutrients therein might support coastal wildlife, ended up uncovering very high levels of mercury in the runoff. The finding raises new questions about how global warming will impact wildlife in the region, one of the foremost exporters of seafood worldwide.

Mermaids, mercury

“There are surprisingly high levels of mercury in the glacier meltwaters we sampled in southwest Greenland,” said Jon Hawkings, a postdoctoral researcher at Florida State University and the German Research Centre for Geosciences. “And that’s leading us to look now at a whole host of other questions such as how that mercury could potentially get into the food chain.”

Together with glaciologist Jemma Wadham, a professor at the University of Bristol’s Cabot Institute for the Environment, Hawkings initially set out to sample water from three different rivers and two fjords next to the Greenland Ice Sheet. Their aim was to understand how nutrients from glacial meltwater can help to support coastal ecosystems.

Although they also measured for mercury, they didn’t expect to find any meaningful concentrations. Which made the levels of this metal they found in the water all the more surprising.

The baseline for mercury content in rivers is considered to be about 1 to 10 ng / L-1. That’s roughly equivalent to a sand grain of mercury in an Olympic pool of water — so, very low. However, the duo found that mercury levels in the water they sampled were in excess of 150 ng / L-1. Mercury levels in the sediment (called “glacial flour” when it’s produced by glaciers) were over 2000 ng / L-1, which is simply immense.

So far, it remains unclear whether mercury levels drop farther away from this ice sheet, as meltwater gets progressively more diluted. It’s also not yet clear whether the metal is making its way into the marine food web, which would likely make it concentrate further (as animals eat plants and each other).

Although the findings are local, the issue could have global ramifications, as they echo findings in other arctic environments. Greenland is an important producer of seafood, with the export of cold-water shrimp, halibut, and cod being its primary industry. If mercury here does end up in the local food web, it could unknowingly be exported to and consumed by people all over the world.

“We didn’t expect there would be anywhere near that amount of mercury in the glacial water there,” said Associate Professor of Earth, Ocean, and Atmospheric Science Rob Spencer, co-author of the paper. “Naturally, we have hypotheses as to what is leading to these high mercury concentrations, but these findings have raised a whole host of questions that we don’t have the answers to yet.”

“For decades, scientists perceived glaciers as frozen blocks of water that had limited relevance to the Earth’s geochemical and biological processes. But we’ve shown over the past several years that line of thinking isn’t true. This study continues to highlight that these ice sheets are rich with elements of relevance to life.”

Roughly 10% of our planet’s dry land is covered in ice, and the results here raise the worrying possibility that they may be seeping mercury into the waters around them. The issue is compounded by the fact that global warming is making these glaciers melt faster, while we still have an imperfect understanding of how the melting process influences the local geochemistry around them.

So far, the team explains that this mercury is most likely coming from a natural source, not from something like fossil fuel use or industrial activity. While this is very relevant for policy-makers, the fact remains that natural mercury is just as toxic as man-made mercury. If it is sourced from natural processes, however, managing its levels in the wild will be much more difficult to do .

“All the efforts to manage mercury thus far have come from the idea that the increasing concentrations we have been seeing across the Earth system come primarily from direct anthropogenic activity, like industry,” Hawkings said. “But mercury coming from climatically sensitive environments like glaciers could be a source that is much more difficult to manage.”

The paper “Large subglacial source of mercury from the southwestern margin of the Greenland Ice Sheet” has been published in the journal Nature Geoscience.

Study finds Greenland ice-sheet has already melted before – and it could again

It seems like a Hollywood blockbuster but it’s actually a real and concerning story: catastrophic sea level rise could be on the way. Researchers analyzed ice core samples taken in the 1960s from a secret Arctic military base and found that the Greenland ice sheet – which has enough water to raise sea levels by 20 feet worldwide – could melt much faster than previously thought.

Image credit: Flickr / Ting Chen

More than 60 years ago, US Army scientists dug up the ice core in northwestern Greenland as part of the Iceworm project – a mission to build a subsurface base to hide hundreds of nuclear warheads. The army created a research base called Camp Century as a cover story, but the base was eventually abandoned and the ice core lay forgotten in a freezer.

Researchers rediscovered the ice samples in 2017 and started investigating them in 2019. They found fragments of fossilized plants that could have bloomed a million years ago, which implies there was once vegetation in a spot now buried with ice. Greenland’s current ice cover was thought to be three million years old, but these fragments say otherwise.

Most of Greenland is now covered by the Greenland Ice Sheet, which spans 656,000 square miles (1.7 million square kilometers) – three times the size of Texas, according to the National Snow and Ice Data Center (NSIDC). If the new research is right and most of Greenland’s ice vanished relatively recently, this isn’t good news for the stability of the current ice sheet.

If all of Greenland’s ice were to melt, the seas would rise by about 24 feet (seven meters), according to a 2019 report by the National Oceanic and Atmospheric Administration. This would be enough to flood most coastal cities around the world. While this won’t happen tomorrow, Greenland’s ice sheet is already melting now six times faster than it was in the 1980s and if things don’t change soon, we could face a worst-case scenario.

“Before humans added hundreds of parts per million of fossil fuels to the atmosphere, our climate was able to melt away the ice sheet. In the future as we continue to warm the planet at an uncontrollable rate, we could force the Greenland ice sheet past some threshold and melt it and raise sea levels,” Drew Christ, the study’s lead author, told Gizmodo.

The US Army started building Camp Century in 1959, followed by the extraction of an ice core measuring 11 feet (3.4 meters) from a depth of 4,488 feet (1,368 m) below the ice. The core went to storage after the army finished the project, first in New York and then in Copenhagen. Following an inventory of materials in 2017, researchers were called on to examine the core.

Christ and the group of researchers noticed “little black things” floating in the water. They placed them under a microscope and discovered fossil twigs and leaves in the frozen sediment. Such plants, probably from a boreal forest, could have only grown if Greenland’s ice sheet was mostly gone. So now the next step will be to figure out how recently that happened.

To date the plants, the researchers looked at isotopes of aluminum and beryllium, which accumulate in minerals when exposed to radiation that filters through the atmosphere. They determined that the soil and the plants last saw sunlight between a few hundred thousand and about a million years ago. The traces of leaf waxes resembled those now found on tundra ecosystems.

The researchers estimated that the present ice sheet persisted at more or less the same size for about 2.6 million years, using geological records and ocean geochemistry. However, the findings showed that ice vanished almost entirely from Greenland during at least one period in the island’s most recent deep freeze – a previously unknown threshold for ice sheet stability.

“This is important as we move forward into a warmer future,” Christ told Gizmodo. “Our climate system has a delicate balance to it. If it changes enough, you can melt away large portions of these ice sheets and raise sea levels — and that would inundate and flood large portions of the most densely populated areas on Earth.”

The study was published in the journal PNAS.

New projections warn that Greenland’s ice sheet will see 60% more melt than we’ve estimated

New research warns that the Greenland ice sheet is likely to melt even more than previously estimated — a solid 60% more.

Bad news keeps piling up for the Greenland ice sheet. A study earlier this month reported that in around 600 years or so, it will melt enough that it won’t ever be able to recover (the ice sheet creates its own microclimate, meaning it is making itself possible right now). Despite this, new research suggests that we’ve underestimated how large the problem truly is.

Melt a-plenty

The team, headed by researchers from the Universities of Liège and Oslo, used multiple climate models with the latest observations, finding that we’re likely to see a 60% greater melting of the Greenland ice sheet by 2100 than previously predicted. That melt will, obviously, contribute to a rising sea level.

“The MAR model (one of the models used for the paper) was the first to demonstrate that the Greenland ice sheet would melt further with a warming of the Arctic in summer. While our MAR model suggested that in 2100 the surface melting of the Greenland ice sheet would contribute to a rise in the oceans of around ten centimeters in the worst-case scenario (i.e. if we do not change our habits),” explains Stefan Hofer, a post-doc researcher at the University of Oslo.

“Our new projections now suggest a rise of 18 cm.”

The results of this paper will be integrated into the next Intergovernmental Panel on Climate Change (IPCC) report, AR6, the team adds. As they will be based on our most up-to-date models, the findings outlined by the paper should be more reliable than anything we’ve had previously.

Greenland’s ice sheet is the second-largest in the world after the Antarctic one, covering some 1.7 million square kilometers. A complete melt of this sheet would cause a rise in ocean levels by up to 7 meters, which is immense. Although the estimations in this paper are nowhere near that figure, they’re still higher than previous estimates, which is cause for concern.

The current paper reports that we’re looking at an 18cm (~7 in) increase in sea levels by 2100, which is 8cm higher than the previous estimation used by the IPCC. The researchers also used their MAR model to ‘downscale’ on previous IPCC scenarios. Keeping the same emission estimates that these used, the current model shows 60% more surface melting of the Greenland ice cap until the end of the century. Downscaling basically means turning a model with coarse resolution (i.e. low detail) into one with a higher resolution (more, finer detail).

“It would now be interesting”, says Xavier Fettweis, researcher and director of the Laboratory,” to analyze how these future projections are sensitive to the MAR model that we are developing by downscaling these scenarios with other models than MAR as we have done on the present climate.”

This was the first attempt to downscale the future scenarios regarding Greenland that the IPCC uses, the team notes. Future efforts to refine our climate models will receive support from various international projects such as the EU’s Horizon 2020, which should help the team gain access to even more cutting-edge data. Since melting processes are influenced by a wide variety of factors, our ability to predict them hinges on having as much reliable data factored in as possible.

The paper “GrSMBMIP: intercomparison of the modelled 1980-2012 surface mass balance over the Greenland Ice Sheet” has been published in the journal The Cryosphere.

Greenland’s ice sheet is poised to melt forever — we have 600 years to stop it

New research suggests that the Greenland Ice Sheet is inching in towards a dangerous threshold: in around 600 years, it will melt enough that the sheet won’t ever recover, no matter what we do, and sea levels remain permanently higher. This scenario assumes that current rates of melt remain constant.

The glaciers and landscape in northeast Greenland, captured in 2014. Here you can see refrozen meltwater ponds from last year’s summer cover with snow that has fallen during the winter months. Image credits Credits: NASA /Michael Studinger.

The team from the National Centre for Atmospheric Science and the University of Reading show that climate change is leading to an irreversible rise in the sea level alongside a declining Greenland ice sheet. Worse yet, this sheet is closing in on a point of no return, past which it will never fully regrow — leaving a permanent mark on the global sea level.

Big Ice, Big Loss

The Greenland ice sheet is roughly three times the size of Texas and stores an important quantity of Earth’s frozen water. Under current melting rates, it contributes around 1mm of sea level rise per year (around one-quarter, 25%, of the total increase). It’s estimated that it lost a total of three-and-a-half trillion tonnes of ice since 2003, even with seasonal growth periods factored in.

Needless to say, that’s a lot of water. Rising seas threaten all coastal areas around the world, and can affect potentially millions of people who live in low-lying areas.

If the current target of the Paris Agreement (keeping global warming from going above 2°C compared to pre-industrial temperatures) is not met, we should expect the sea level to rise by several meters and significant ice loss, the authors note. Both would last for tens of thousands of years, and the worse global warming gets, the more dramatic these shifts would be.

The current paper shows that even if temperatures are brought back under control at a later time, the Greenland ice sheet will never fully regrow after it passes its critical threshold. If that point is passed, the sea level would permanently rise by at least 2 meters (with other sources adding to that figure).

Being so large, the sheet has a significant cooling effect on its local climate. In essence, there’s so much ice in Greenland that it’s making Greenland colder and more icy — not a bad trick. But if the sheet declines, local temperatures would increase, which increases melting rates, and snowfall levels would drop dramatically, which would slow down the formation of ice. The team estimates that if the Greenland ice sheet retreats from the northern part of Greenland, that area would remain permanently ice-free. All in all, we have around 600 years before that threshold is passed, the team estimates based on data from the Fifth Assessment Report of the Intergovernmental Panel on Climate Change.

The team simulated the effects of the Greenland ice sheet melting under a range of scenarios, from minimal warming to worst-case conditions. All scenarios led to a decline in size of the sheet and contributed to rising sea levels to one extent or another.

So what’s to be done? Well we need to stop and then reverse climate warming before that threshold is reached.

“Our experiments underline the importance of mitigating global temperature rise. To avoid partially irreversible loss of the ice sheet, climate change must be reversed — not just stabilised — before we reach the critical point where the ice sheet has declined too far,” says Professor Jonathan Gregory, climate scientist from the National Centre for Atmospheric Science and University of Reading, a co-author of the paper.

There were some scenarios the team found where the ice sheet could be stabilized before reaching its point of no return. All of them, however, hinged on steps being taken ahead of time to reverse global warming.

The paper “Large and irreversible future decline of the Greenland ice sheet” has been published in the journal The Cryosphere.

Scientists discover huge fossil lake under Greenland

Greenland’s relief is every bit as varied and spectacular as any place on Earth, but we can’t really see it because of all the ice. But if you could peer beneath this ice (say, with satellite radar data), you could see some of this ice-hidden relief. This is exactly how researchers discovered what they believe to be an ancient, ‘fossil’ lake. They think it’s as big as the states of Delaware and Rhode Island combined, or about a third of Wales.

Depiction of the ancient lake bed (surrounded by a red line) and the river valleys (in yellow). Credits: Paxman et al.

Researchers routinely use satellite data to analyze Greenland. They’re not usually looking for submerged geography, but they’re looking to see how much the ice sheet is thinning. In order to do this, they use airborne geophysical instruments that send radar signals — signals which can penetrate ice but bounce off from the underlying solid surface.

So with this approach, they can catch a glimpse of the geological structure beneath the ice.

“This could be an important repository of information, in a landscape that right now is totally concealed and inaccessible,” said Guy Paxman, a postdocste at Columbia University’s Lamont-Doherty Earth Observatory and lead author of the report. “We’re working to try and understand how the Greenland ice sheet has behaved in the past. It’s important if we want to understand how it will behave in future decades.”

A depiction of the ancient lake and its geologic surroundings. Credits: Paxman et al.

The geomorphological mapping carried out by Paxman and his colleagues suggests more than just an isolated lake: they found evidence of a sprawling network of bedrock channels preserved in the subglacial landscape of northwest Greenland. The channels exhibit steep V-shaped valleys and a complex, branching pattern, all of which are diagnostic characteristics of fluvial valley networks. In other words, what is now covered under a layer of ice was once a thriving river-lake network which may harbor fossils from hundreds of thousands or even millions of years ago, researchers believe.

The lake sediments could also hold another piece of valuable evidence: they could show us how and when Greenland became covered in ice. This could help us make better sense of the climate change we’re seeing now and develop better models of how Greenland ice is melting. It’s doable. With the top of the sediments 1.8 kilometers (1.1 miles) below the current ice surface, drilling to them would be a challenging task, but not an impossible one.

Meanwhile, Greenland’s ice sheet continues to melt at an accelerated pace due to rising temperatures. If it were to melt completely, the sheet has enough ice to raise global sea levels by 7 meters (24 feet). While this won’t happen anytime soon, even a fraction of that would be enough to cause catastrophic damage, displacing billions of people in the process.

The study was published in the journal Earth and Planetary Science Letters.

Greenland lost 600 billion tons of ice last summer, satellite data shows

For many scientists, Greenland is considered “ground zero” for climate change, a place where the effects of global warming are most evident – including growing temperatures, warming oceans, and melting ice.

Last summer, Greenland went through an exceptionally warm season with record-breaking temperatures. This led to the loss of 600 billion tons of ice, which is enough to raise global sea levels 2.2 millimeters in two months, according to a new study.

NASA’s Jet Propulsion Laboratory (JPL) and the University of California looked at satellite data, which showed the surprising rate loss of ice in the area. Last year was the hottest on record for the Arctic, with the annual minimum extent of sea ice in the region its second-lowest on record.

“We knew this past summer had been particularly warm in Greenland, melting every corner of the ice sheet,” lead author Isabella Velicogna, senior project scientist at NASA’s JPL and a professor at the University of California, Irvine, said in a statement. “But the numbers really are enormous.”

The study took its data from satellites that were designed to measure changes to the Earth’s gravitational pull that result from changes in mass, including water. It showed that the ice losses registered last summer are more than double Greenland’s 2002-2019 yearly average.

But it’s not just Greenland. Antarctica continues to lose mass as well, the researchers said. “In Antarctica, the mass loss in the west proceeds unabated, which will lead to an even further increase in sea-level rise,” Velicogna said, claiming they also saw a mass gain in East Antarctica due to an uptick in snowfall.

Glaciers around the world are melting because of global warming, with Greenland as one of the most affected areas. Last year, a study showed ice is being lost from Greenland seven times faster than it was in the 1990s. This means 400 million people could be at risk of flooding every year by the end of the century due to sea-level rise.

Greenland’s ice sheet is experiencing an increase in ice slab thickness in its interior regions, another study showed. These ice sheets are normally porous, allowing meltwater to percolate (drain through) them, but the extra thickness makes them impermeable — so all the meltwater is draining into the ocean.

With most attention now focused on the coronavirus, the study helps to show the consequences that further global warming would have across the world. Countries agreed through the Paris Agreement to limit the temperature increase to 2 degrees Celsius, but much further action is needed to meet that goal.

The study was published in the journal Geophysical Research Letters.

Greenland and Antarctica are losing ice six times faster than in the 1990s

Global warming is kicking in across the globe and Greenland and Antarctica are among the worst affected regions.

Both are losing ice six times quicker than in the 1990s, and if that continues sea level rise will increase an extra 17 centimeters by 2100 — in line with the worst-case scenario set by UN experts.

Credit Wikipedia Commons

Those are the main conclusion of an analysis by experts from 50 international organizations, who have used data from 26 studies to calculate changes in the mass of the ice sheets in Greenland and Antarctica between 1992 and 2018.

The results were published in two articles in the online version of the journal Nature in 2018 (Antarctica) and 2019 (Greenland). The researchers now reported the combined data from the two areas in a press release distributed by the University of Leeds, UK.

The figures show that Greenland and Antarctica lost 6.4 trillion tons of ice between 1992 and 2017, which raised the level of the world’s seas by 17.8 millimeters. Of the total sea-level rise, 10.6 millimeters (60%) were due to Greenland ice losses and 7.2 millimeters (40%) to Antarctic losses.

The combined rate of ice loss has increased six-fold in just three decades, from 81 billion tons per year in the 1990s to 475 billion tons per year in the 2010s. This means, according to the authors, that the polar ice sheets are now responsible for a third of all sea-level rise.

“If Antarctica and Greenland continue to alienate themselves with the worst-case scenario of global warming, they will cause an additional 17 centimeters to rise in sea level at the end of the century,” said in a statement Andrew Shepherd of the University of Leeds, adding that 400 million people would be at risk.

The loss of the ice sheets coincided with several years of intense melting of the Greenland surface, according to these authors, which said that the heatwave in the Arctic last summer should set a new record. Antarctica and Greenland are losing ice five and seven times faster than in the 1990s, respectively.

In its fifth assessment report, the United Nations Intergovernmental Panel on Climate Change (IPCC) predicted that the global sea level would rise by 53 centimeters by 2100 and it is estimated that this would put 360 million people at risk of coastal flooding.

“We cannot know whether it is too late to stop climate change. Urgent and drastic measures are needed to decrease the contribution of CO2 and other polluting gases to the atmosphere, and still, we don’t know if it will be enough,” said Gorka Moyano, one of the researchers involved in the studies.

Greenland is losing ice seven times faster than in the 1990s

Greenland’s rate of ice loss is increasing faster than expected, a new metastudy reports.

The increased influx of water from Greenland’s ice sheet puts us on track for sea-level rise consistent with the Intergovernmental Panel on Climate Change’s (IPCC) high-end climate warming scenario. Projections for this scenario estimate that coastal flooding will displace 400 million people by 2100.

Image credits Jean-Christophe Andre.

The study is a collaboration between 96 polar scientists from 50 international organizations — The Ice Sheet Mass Balance Inter-comparison Exercise (IMBIE) team — and takes the most complete look at Greenland’s long-term ice loss to date. It combined 26 separate surveys to track changes in the ice mass of Greenland between 1992 and 2018. Data from 11 different satellite missions was used to measure the ice sheet’s changing volume, flow, and mass.

Melting quick

“On current trends, Greenland ice melting will cause 100 million people to be flooded each year [by 2100], so 400 million in total due to all sea level rise,” says Professor Andrew Shepherd at the University of Leeds, one of the study’s co-lead authors.

Melt rate in Greenland has risen from 33 billion tons, on average, per year in the 1990s to 254 billion tons per year over the last decade. In total, the island lost roughly 3.8 trillion tons of ice since 1992.

The IPCC mid-warming scenario set out in 2013 estimated 60 centimeters of sea-level rise by 2100, with associated coastal flooding displacing an estimated 360 million people. The rates of melt reported on in this study push those estimates by an additional 5 to 12 cm — consistent with the projection for the high-warming climate scenario.

“As a rule of thumb, for every centimeter rise in global sea level another six million people are exposed to coastal flooding around the planet,” Professor Shepherd explains.

The report shows that half of the ice losses recorded between 1992 and today have been caused by higher average temperatures, which promoted surface melting. The rest, around 48% of the total ice mass lost, was caused by increased glacier flow into the ocean due to warmer waters. Melting peaked 335 billion tonnes per year in 2011 but has since decreased to 238 billion tonnes per year “as atmospheric circulation favored cooler conditions”.

https://www.youtube.com/watch?v=HlApT0-2LT4

The team notes that this lower rate is still seven times higher than that in the 1990s, and that the dataset didn’t include all of 2019. Higher rates of melt expected in the summer could push Greenland to see record quantities of ice loss.

“Satellite observations of polar ice are essential for monitoring and predicting how climate change could affect ice losses and sea level rise” said Erik Ivins at NASA’s Jet Propulsion Laboratory in California, and co-lead author of the study.

Researchers from the European Space Agency (ESA) and the US National Aeronautics and Space Administration (NASA) also took part in the IMBIE report.

The paper “Mass balance of the Greenland Ice Sheet from 1992 to 2018” has been published in the journal Nature.

Greenland set to accelerate sea level change in the near future

Greenland’s contribution to sea-level rise is increasing, as climate change makes the region release meltwater into the ocean.

Image via Pixabay.

Greenland’s ice sheet is experiencing an increase in ice slab thickness at its interior regions. These ice sheets are normally porous, allowing meltwater to percolate (drain through) them, but the extra thickness makes them impermeable — so all the meltwater is draining into the ocean.

The process could see the country’s contribution to sea level rise increase by as much as 2.9 inches by 2100.

Thicc ice

“Even under moderate climate projections, ice slabs could double the size of the runoff zone by 2100,” said Mike MacFerrin, a CIRES (Cooperative Institute for Research In Environmental Sciences) and University of Colorado Boulder researcher who led the new study. “Under higher emissions scenarios, the runoff zone nearly triples in size.”

Runoff from ice slabs only amounts to a one-millimeter increase in global sea levels so far, the team explains, but that contribution will expand substantially under climate warming.

In the year 2000, Greenland’s runoff zone — the region of the ice sheet where runoff contributes to sea level rise — was roughly equivalent to the size of New Mexico. Between 2001 and 2013, it expanded by an average of two American football fields per minute, reaching roughly 65,000 sq km.

Even under a moderate emissions scenario, the team adds, it could reach the size of Colorado by 2100. That would raise sea levels by an extra 7-33 mm (one-quarter to one inch) by the same timeframe. Under a high emissions scenario, the situation looks even bleaker: the runoff zone could increase by the size of Texas, according to the new paper, contributing an extra 17-74 mm (half-inch to nearly three inches) of sea-level rise.

The runoff estimates from ice slabs are in addition to other sources of sea-level rise from Greenland, such as calving icebergs.

The team explains that Greenland’s ice sheets are made of layers with different textures. Fresh snow that falls each winter either melts into surface lakes or builds-up and helps compact older snow into glacial ice. Snow that partially melts over summer later re-freezes into thin ice “lenses” between 2 to 5 mm (one or two inches) thick within the compacted snow.

Normally, meltwater can percolate through and around ice lenses, refreezing in place without running off to sea. As mean temperatures over the Arctic increase and melting events become more frequent and extreme, however, these ice lenses solidify into slabs between 1 and 16-meter (3- to 50-foot) thick. These slabs block water from flowing through, which ends up flowing downhill into the ocean.

Climate warming is also increasing the quantity of meltwater in Greenland. In July of 2012, snow and ice melted from 97% of Greenland’s ice sheet surface, which the team says has never before been seen the 33-year-long satellite record. This spring, which was particularly warm and sunny in Greenland, resulted in a record-setting 80 billion tons of Greenland ice melted.

“As the climate continues to warm, these ice slabs will continue to grow and enhance other meltwater feedbacks,” said Mahsa Moussavi, a coauthor on the paper. “It’s a snowball effect: more melting creates more ice slabs, which create more melting, which creates again more ice slabs.”

All in all, this process will fundamentally alter the ice sheet’s equilibrium. The team warns that we need to understand Arctic feedbacks like this one because they show just how much, and how quickly, a warming climate can change Earth’s most vulnerable regions.

“Humans have a choice about which way this goes,” MacFerrin said.

The paper “Rapid expansion of Greenland’s low-permeability ice slabs” has been published in the journal Nature.

Iceland.

Our emissions could melt all the ice in Greenland by the year 3000 — and raise sea levels by 24 ft

Greenland may actually be green by the end of the millennium if greenhouse emissions continue unabated.

Iceland.

Image credits Marcel Prueske.

New research shows that, if greenhouse gas emissions continue on their current trajectory, Greenland could lose 4.5% of its ice by the end of the century, and all of it by the year 3000. That 4.5% loss of ice is equivalent to roughly 13 inches of sea level rise, the team explains.

Actually Green land

“How Greenland will look in the future — in a couple of hundred years or in 1,000 years — whether there will be Greenland, or at least a Greenland similar to today, it’s up to us,” said first author Andy Aschwanden, a research associate professor at the University of Alaska Fairbanks Geophysical Institute.

Greenland houses a lot of ice — around 660,000 square miles of solid ice sheet, which contains around 8% of all the planet’s fresh water. Between 1991 and 2015, melting here has added about 0.02 inches per year to the sea level. Needless to say, we need to know how all that ice is faring and whether there’s any cause for concern. Turns out that there is.

The team used recent topography (landscape) data of Greenland’s terrain today to model how its ice sheets will evolve in the future. This data was recorded by a NASA airborne science campaign (Operation IceBridge) during which aircraft fitted with a full suite of scientific instruments scanned Greenland’s ice sheets recording its surface, the individual layers within, and the shape of the bedrock. On average, Greenland’s ice sheet is 1.6 miles thick, but there was a lot of variation.

A wide range of scenarios concerning ice loss and changes in sea level are possible based on how greenhouse gas concentrations and atmospheric conditions evolve. The team ran 500 simulations for each emission scenario using the Parallel Ice Sheet Model, developed at the Geophysical Institute, to create a picture of how Greenland’s ice would respond to different climate conditions. The model included parameters on ocean and atmospheric conditions as well as ice geometry, flow, and thickness.

Under a business as usual scenario, we could see around 24 feet to global sea level rise by the year 3000 due to melting in Greenland alone — which would put much of San Francisco, Los Angeles, New Orleans and other cities under water. However, if we do manage to slash greenhouse gas emissions significantly, the prospects improve. Reduced emission scenarios showed between 8% to 25% melting of Greenland’s ice, which would lead to approximately 6.5 feet of sea level rise

Projections for both the end of the century and 2200 tell a similar story. A wide range of outcomes are possible, including saving the ice sheet, but it all depends on emission levels, the team explains.

The team explains that modeling ice sheet behavior is tricky because ice loss is primarily driven by the retreat of outlet glaciers. These are the glaciers at the margin of the ice sheets, and they ‘drain’ ice from deeper in the sheets through through-like structures in the bedrock. This study was the first to include these outlet glaciers in its modeling and found that their discharge could contribute as much as 45% of the total mass of ice loss in Greenland by 2200. Outlet glaciers come into contact with water, the team explains, which makes ice melt much faster than air. The more ice that comes into contact with water, the faster the rate of melting — which creates a feedback loop that dramatically affects the ice sheet’s stability.

Previous research lacked data as comprehensive as that recorded by IceBridge, so it couldn’t simulate the ice sheets’ evolution in such detail.

“Ice is in very remote locations,” says Mark Fahnestock, a researcher at the University of Alaska Fairbanks Geophysical Institute and paper co-author. “You can go there and make localized measurements. But the view from space and the view from airborne campaigns, like IceBridge, has just fundamentally transformed our ability to make a model to mimic those changes.”

“What we know from the last two decades of just watching Greenland is not because we were geniuses and figured it out, but because we just saw it happen,” he adds. As for what we will see in the future, “it depends on what we are going to do next.”

The paper “Contribution of the Greenland Ice Sheet to sea level over the next millennium” has been published in the journal Science Advances.

Iceberg.

Arctic ecosystems “highly responsive” to climate change — and very hard to fix once broken

Climate change is impacting the Arctic far quicker than we’ve assumed, an international team of researchers reports. Other research looking into how Arctic life fared after the meteorite impact that wiped out the dinosaurs gives us a glimpse into how ecosystems in the area might evolve under climate change.

Iceberg.

Image credits Rolf Johansson.

Ecosystems in the Arctic undergo rapid, dramatic, and long-lasting changes in response to climate shifts — even those of average magnitude, according to a new study published in Environmental Research Letters. The study, conducted by an international research team led by members from the University of Maine, finds a “surprisingly tight coupling” between climate shifts and environmental responses in the Arctic. The paper thus overturns previous assumptions that environmental responses are delayed or dampened by internal ecosystem dynamics, allowing only significant climate shifts to have an effect on local ecosystems.

The heat is on

“Our analyses reveal rapid environmental responses to nonlinear climate shifts, underscoring the highly responsive nature of Arctic ecosystems to abrupt transitions,” the study’s abstract reads.

After 1994, mean air temperatures over West Greenland (as recorded in June) were 2.2°C higher than baseline, the team reports, and have increased by an additional 1.1°C since 2006. Mean winter precipitation also doubled in quantity (from 20mm to 40mm) over the area after 1994.

The findings come from over 40 years’ worth of weather data and paleoecological reconstructions. The team explains that these “abrupt climate shifts” were accompanied by “nearly synchronous” environmental responses in the area, including increased ice sheet discharge and dust, and advanced plant phenology (i.e. earlier onset of the life cycles of plants in the area). Lakes in the area experienced earlier ice-outs and greater diversity of algae.

In light of these findings, the team cautions that Arctic ecosystems are much more responsive to abrupt transitions — even moderate magnitude ones — than assumed. The strength of climate forcing (i.e. warming) in the area has also been underestimated, they add. Understanding how these ecosystems respond to abrupt climate change is key to predicting their evolution in the future and managing potentially damaging shifts says Jasmine Saros, the paper’s lead author.

“We present evidence that climate shifts of even moderate magnitude can rapidly force strong, pervasive environmental changes across a high-latitude system,” she says.

“Prior research on ecological response to abrupt climate change suggested delayed or dampened ecosystem responses. In the Arctic, however, we found that nonlinear environmental responses occurred with or shortly after documented climate shifts in 1994 and 2006.”

How does this pan out?

Penguins.

Penguins don’t live in the Arctic but they’re cute, so here’s a picture of some.
Image credits Siggy Nowak.

Another unrelated study published in the journal Palaeontology looked at how life on the other end of the planet — Antarctica — recovered after the impact of Chicxulub, the dinosaur-killing meteorite. This impact triggered a massive, planet-wide extinction event known as the Cretaceous-Paleogene (K-Pg) mass extinction some 66 million years ago.

Although the effects of this impact (e.g. transient cooling, global darkness, and expansion of anoxic waters) were “probably short-lived, […] biogeochemical cycling and ecosystem function remained disturbed for an extended period”. It took local marine ecosystems roughly one million years to return to pre-extinction levels, they explain.

The K-Pg event was caused by the impact of a 10 km asteroid on the Yucatán Peninsula, Mexico, and took place while our planet was already in the throes of environmental instability caused by a major volcanic episode. In the end, Chicxulub’s visit would wipe out around 60% of the marine species around Antarctica, and 75% of species around the world. This turned out to be quite a fortunate development for us humans, as the impact fundamentally changed the evolutionary history of life on Earth. Most of the animal groups you know today, including us mammals, were only able to rise as a direct consequence of this impact.

“This study gives us further evidence of how rapid environmental change can affect the evolution of life,” says Dr. Rowan Whittle, a palaeontologist at British Antarctic Survey and the study’s lead author.

“Our results show a clear link in the timing of animal recovery and the recovery of Earth systems.”

For over 320,000 years after the extinction, the team reports, the Antarctic sea floor was dominated by burrowing clams and snails. It took roughly one million years for the number of species to recover to pre-extinction levels.

“Our discovery shows the effects of the K-Pg extinction were truly global, and that even Antarctic ecosystems, where animals were adapted to environmental changes at high latitudes like seasonal changes in light and food supply, were affected for hundreds of thousands of years after the extinction event.”

Now, needless to say, the K-Pg extinction event was way more abrupt and dramatic than the shifts we’re causing in the Earth’s climate today. And this study focuses on its effects in Antarctica, not the Arctic. However, it does serve as an adequate case-study to see how long such ecosystems need to recover from major environmental shocks.

And climate change (plus human activity) is a major environmental shock. It’s much slower than an asteroid impact, sure, but it’s still happening unbelievably fast from a geological and evolutionary point of view. The first study we’ve discussed here shows that Arctic ecosystems do feel the heat, and feel it fast. Life here is very specialized to thrive in its frigid niche and if we let these ecosystems collapse, the same ancient dynamics that Whittle’s team found in the Antarctic will likely apply — our Arctic will only recover as the Earth’s systems recover.

The paper “Arctic climate shifts drive rapid ecosystem responses across the West Greenland landscape” has been published in the journal Environmental Research Letters.

The paper “Nature and timing of biotic recovery in Antarctic benthic marine ecosystems following the Cretaceous–Palaeogene mass extinction” has been published in the journal Palaeontology.

A new impact crater has been found under more than a mile of ice in northwest Greenland. Credit: NASA Goddard.

NASA finds a second huge impact crater beneath Greenland’s ice sheet

A new impact crater has been found under more than a mile of ice in northwest Greenland. Credit: NASA Goddard.

A new impact crater has been found under more than a mile of ice in northwest Greenland. Credit: NASA Goddard.

Scientists didn’t think they would be able to find evidence of ancient impact craters in places such as Greenland or Antarctica, which should have been cleared away by erosion by underlying ice. But, in November, researchers found a huge 30-kilometer-wide crater (19 miles) beneath Greenland’s Hiawatha Glacier. It was the first meteorite impact found beneath an ice sheet, a breakthrough moment in geoscience that combined the latest imaging technologies. Now, researchers report finding an even larger crater beneath Greenland’s thick ice. With a width of 36.5 km (22 miles), if confirmed, the new crater would be the 22nd largest impact crater found on Earth.

Beneath the ice

The new site was identified just 183 km (114 miles) from Hiawatha, but, judging from current evidence, the two impacts weren’t likely made during the same time. Both are fairly recent though. Scientists estimate that Hiawatha is no more than three million years old, while the new impact site in northwest Greenland was likely formed by an asteroid impact within the past 2.6 million years. Although it doesn’t have a formal name yet, researchers are considering naming it the Paterson crater, in honor of the late glaciologist Stan Paterson, who helped reconstruct climate data for the past 100,000 years using ice cores from Greenland.

“We’ve surveyed the Earth in many different ways, from land, air, and space—it’s exciting that discoveries like these are still possible,” said Joe MacGregor, a glaciologist with NASA’s Goddard Space Flight Center in Greenbelt, Maryland, who made contributions to the discovery of both craters.

MacGregor was inspired by last year’s discovery to scour topographic maps for more signs of other craters. He eventually noticed a circular pattern in an ice surface map made using data from NASA’s Terra and Aqua satellites. His suspicions were confirmed by raw radar data, including those collected by NASA’s Operation IceBridge, which were used to study the topography of the bedrock beneath the ice.

The images that MacGregor and colleagues assembled show all the hallmarks of an impact crater, including a flat, bowl-shaped depression in the bedrock, surrounded by an elevated rim and centrally located peaks. Measurements also revealed a negative gravity anomaly over the area, which is also characteristic of impact craters.

“The only other circular structure that might approach this size would be a collapsed volcanic caldera,” MacGregor said in a statement. “But the areas of known volcanic activity in Greenland are several hundred miles away. Also, a volcano should have a clear positive magnetic anomaly, and we don’t see that at all.”

Given the proximity of the two craters, it’s plausible that a double asteroid system impacted the area. In order to investigate this possibility, the researchers studied the erosion rates of the two craters. The findings suggest that the new crater is far more eroded than the Hiawatha crater, and consequently older. Previously, two pairs of geographically close craters in Ukraine and Canada were also found to be unrelated.

“The existence of a third pair of unrelated craters is modestly surprising but we don’t consider it unlikely,” MacGregor said. “On the whole, the evidence we’ve assembled indicates that this new structure is very likely an impact crater, but presently it looks unlikely to be a twin with Hiawatha.”

The findings appeared in the journal Geophysical Research Letters.

Meltwater slides off Greenland's massive ice sheet into the ocean during hot summer days. Credit: Woods Hole Oceanographic Institution.

Greenland melting is ‘off the charts’ — It’s unprecedented in the last 400 years, scientists warn

Meltwater slides off Greenland's massive ice sheet into the ocean during hot summer days. Credit: Woods Hole Oceanographic Institution.

Meltwater slides off Greenland’s massive ice sheet into the ocean during hot summer days. Credit: Woods Hole Oceanographic Institution.

Greenland’s ice sheet is melting faster than at any point in the last four centuries, researchers warn in a new study. The findings are especially worrisome since Greenland’s ice sheet — which is 1.5-kilometer thick and covers 1,710,000 square kilometers — could raise sea levels by up to seven meters if it completely vanished. “From a historical perspective, today’s melt rates are off the charts, and this study provides the evidence to prove this,” said Sarah Das, a glaciologist at Woods Hole Oceanographic Institution (WHOI) and co-author of the study.

A history trapped in ice

Scientists had known that Greenland’s massive ice sheet is melting at an accelerated rate, based on satellite observations. But the question on everybody’s mind has always been how fast. And because reliable satellite monitoring of the area only dates back to the early 1990s, it’s also challenging to gauge exceptional warming events from background warming rates. For instance, 2012 was particularly intense, with 97% of the entire ice sheet experiencing surface melting for a few days.

In a new study, an international team of researchers found that while 2012 was indeed unusually warm for Greenland, the ice sheet’s dramatic warming may simply be a preview of what’s in store for the future. Their unprecedented analysis, which offers a melting record going back centuries, shows that the ice sheet has been melting at a faster rate than previous estimated, even faster than air temperatures are increasing.

“Melting of the Greenland Ice Sheet has gone into overdrive. As a result, Greenland melt is adding to sea level more than any time during the last three and a half centuries, if not thousands of years,” said Luke Trusel, a glaciologist at Rowan University’s School of Earth & Environment and former post-doctoral scholar at Woods Hole Oceanographic Institution, and lead author of the study. “And increasing melt began around the same time as we started altering the atmosphere in the mid-1800s,” said the researcher, alluding to a human activity as the likely culprit for this warming.

In order to come up with a historical record of Greenland’s ice melt, the research team drilled ice cores from the ice sheet at sites more than 1,800 meters above sea level. Researchers drilled at such high elevations for good reason. Greenland experiences seasonal melt during the warm summer days, and at low elevations, the melting is more intense. At such locations, meltwater runs off the ice sheet and into the ocean, contributing to sea level rise — but in the process, no record of the melt remains. Contrary, at higher elevations, the meltwater quickly refreezes due to contact with the snowpack underneath. Instead of escaping the ice sheet, the short-lived meltwater forms icy bands that stack up layers of densely packed ice over time. In the case of the cores drilled by the researchers, the record goes back into the 17th century.

Traffic-pole-sized ice cores were sent to labs in the United States where their physical and chemical properties were assessed. Dark bands running horizontally across the cores record the strength of the melting for a given year. Thicker bands signify years of higher melting, while thinner bands indicate years of less intense melting.

The results from the ice cores were combined with observations from satellites and climate models. The researchers claim that the thickness of the annual melt layers can also track how much melting was occurring at different sites, at the lower-elevations edges of the ice sheet. In other words, their new findings cover melting broadly, across the much of the ice sheet.

Writing in the journal Nature, the authors conclude that runoff in Greenland started to steadily rise when the first signs of climate change hit the Arctic, in the mid-19th century. However, it accelerated dramatically in the past 20 years, at a rate six-fold higher than before the Industrial Revolution.

“We have had a sense that there’s been a great deal of melting in recent decades, but we previously had no basis for comparison with melt rates going further back in time,”  Matt Osman, co-author of the new study, said in a statement. “By sampling ice, we were able to extend the satellite data by a factor of 10 and get a clearer picture of just how extremely unusual melting has been in recent decades compared to the past.”

The authors also note that Greenland’s ice sheet is much more vulnerable to melting than before. Data suggests that even small changes in temperature caused exponential increases in melting in recent years — a non-linear response that points to feedback effects. Since surface temperatures in the Arctic are rising faster than any other place on Earth, these findings don’t bode well for the future of Greenland’s ice sheet — and with it, our own.

Illustration of newly discovered immense crater in Greenland. Credit: Nasa/Cryospheric Sciences Lab/Natural History Museum of Denmark.

Scientists find huge 19-mile impact crater under Greenland’s ice sheet

Researchers recently identified a huge bowl-shaped crater measuring a staggering 19 miles (31 km) across under half a mile of Greenland ice. The immense crater was likely formed by the impact of a mile-wide iron meteorite, which must have unleashed 47,000,000 times the energy of the nuclear bomb dropped on Hiroshima at the very end of WWII. The biggest question on everybody’s mind right now is when it all happened.

Illustration of newly discovered immense crater in Greenland. Credit: Nasa/Cryospheric Sciences Lab/Natural History Museum of Denmark.

Illustration of the newly-discovered immense crater in Greenland. Credit: Nasa/Cryospheric Sciences Lab/Natural History Museum of Denmark.

Kurt Kjær, a Professor at the Natural History Museum of Denmark in Copenhagen, suspected an impact crater might be hidden away under Greenland’s ice after NASA radar images showed a massive depression of the bedrock beneath the Hiawatha glacier, in the northwestern part of the island.

In May 2016, one year after the satellite images were released, scientists flew over the glacier pointing a cutting-edge ice-penetrating radar onto the glacier to map the underlying rock. The 3-D images clearly show all the hallmarks of an impact crater — a 19.3-mile-wide circular feature with a rim around it and an elevated central region.

The crater’s basin is about 300 meters deep, suggesting it was perhaps made by a one-mile-wide meteorite. This immediately classes the impact site among the top 25 largest known craters on Earth. According to the researchers, the impact would have melted and vaporized approximately ~20 km3 of rock.

“There would have been debris projected into the atmosphere that would affect the climate and the potential for melting a lot of ice, so there could have been a sudden freshwater influx into the Nares Strait between Canada and Greenland that would have affected the ocean flow in that whole region,” co-author John Paden, Associate Professor of electrical engineering and computer science at Kansas University, told the AFP.

Kurt Kjær collecting sediment samples from the crater's dranage system. Credit: Natural History Museum Denmark.

Kurt Kjær collecting sediment samples from the crater’s drainage system. Credit: Natural History Museum Denmark.

The meteorite was likely mostly made of iron, judging from geochemical tests performed on particles of shocked quarts collected from a nearby floodplain.

“Beyond the grains in the sediment sample that we interpret to be possible ejecta, no ejecta layer associated with this structure has yet been identified. Despite the absence of such additional evidence, an impact origin for the structure beneath Hiawatha Glacier is the simplest interpretation of our observations,” the authors wrote in their new study.

Black triangles represent elevated rim picks from the radargrams, and the dark purple circles represent peaks in the central uplift. Credit: Science Advances.

Black triangles represent elevated rim picks from the radargrams, and the dark purple circles represent peaks in the central uplift. Credit: Science Advances.

When exactly did the impact actually takes place is not at all certain. Kjær and colleagues are confident that the crater is no older than 3 million years, the time when ice began to cover Greenland.

“The age of this impact crater is presently unknown, but from our geological and geophysical evidence, we conclude that it is unlikely to predate the Pleistocene inception of the Greenland Ice Sheet,” the authors wrote in the journal Science Advances

As for the lower limit, radar images show that the deepest layers of the glacier that are older than 12,000 years are very deformed compared to upper layers and are filled with lumps of rock. To be sure, researchers will have to use radiometric dating techniques on material from the crater — that means drilling through half a mile of ice. It might take a few years before this happens, however.

 

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

‘Earliest evidence of life’ may just be really old rock

Two years ago, researchers at the University of Wollongong in Australia caused quite a commotion when they claimed that 3.7-billion-year-old fossils found in Greenland rocks represent the oldest evidence for life. What the researchers found was assumed to be not fossilized life per se, but rather structures called stromatolites made by bacterial colonies — a type of biological “footprint”. But an independent research team that verified the findings turned up with something different: they concluded that the ancient carvings in the rock are not biological at all.

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

The alleged stromatolites, trapped within layered rocks from Greenland. Credit: Allen Nutman

The alleged stromatolites were recovered from the Isua supracrustal belt in southwest Greenland, which is home to some of the oldest rocks ever, extending up to 4.2 billion years old. Isua rocks are metamorphic — sedimentary rocks that were subjected to extreme temperature and pressure, changing dramatically in the process. Because such conditions are known to deform the original rock, critics were concerned that the stromatolite fossils — if there were any genuine ones in the first place — had been altered.

Scientists could not find any biosignatures or organic chemical compounds but the cone-shaped structures, measuring 1 and 4 cm (0.4 and 1.6 in) in height, were seen as enough proof of ancient biological activity. Stromatolites are formed by colonies of bacteria that slowly and gradually stack fine layers of sediments atop of each other, forming a column-like structure.

In their 2016 study, Australian researchers wrote that they had ruled out all other possibilities and that the stromatolites likely seem the oldest evidence for life on Earth. Skeptical, as all scientists should be, Abigail Allwood, a geologist from the California Institute of Technology and Minik T. Rosing, a geochemist at the University of Copenhagen, traveled to the Isua site to study the rocks.

The team performed a complex analysis of the samples, studying them from the front and sides, and found that the structures showed signs of both compression and expansion. This suggests that the structures were shaped by surrounding rock, not internal biological activity. What’s more, when the researchers performed a 3-D observation analysis, the structures were not cone-shaped anymore but rather looked like ridges. In other words, the structures were not forged by creatures but by tectonic processes. The fact that the region of Greenland where the structures were found is very geologically active seems to add weight to the new study’s conclusions, whose findings appeared in Nature.

Geologist Allen Nutman, who led the team at the University of Wollongong, is still standing by his initial assessment pointing to stromatolites and claims the new study fails to provide enough evidence to the contrary.

“This is a classic comparing apples and oranges scenario, leading to the inevitable outcome that ours and their observations do not exactly match,” Nutman told Gizmodo. “Allwood never took up the offer made by our team to lend our samples to them, so they could make an independent assessment of the best-preserved original specimens.”

Perhaps further analysis might help finally settle the affair. Meanwhile, seeing how the Greenland stromatolites are challenged, the next oldest evidence for life that scientists have found dates back to 3.45 billion years ago. However, using a different approach based on DNA ‘molecular clock’, scientists say that life first appeared on Earth even earlier — around 4.5 billion years ago.

Walrus upper jaw bone.

Ivory trade made Greenland great, then barren again

The secret of Greenland’s quick rise to prominence, as well as its rapid decline, may have been walrus tusks.

Walrus head.

Image via Wikipedia.

Sometime in the late 10th century in Iceland, one Erik Thorvaldsson was having a pretty bad day.

Born in Norway, Erik and his family were forced to flee to Iceland after his father committed “some killings“. Erik was about 10 years old when this happened but, he realized today, he didn’t take the lesson to heart. Following in his father’s footsteps, Erik had also committed manslaughter — and was now forced into exile from Iceland.

This paternal murderous streak, however, would echo through time and help shape the destiny of Europe’s northern countries.

“Looks green to me!”

Erik sailed with his family and slaves, intent on finding his fortune on the wild shore to the southwest of Iceland. Icelandic Sagas hold that he christened the massive island Grœnland (‘Greenland’) and stayed there — thus creating the first Norse settlement on Greenland.

Nestled in the frigid waters between the North Atlantic and the Arctic Ocean, however, Greenland is decidedly un-green. Historians are still split on whether the lands were lusher back in the days of the Vikings, or whether Erik simply had a knack for PR campaigns and an interest in tempting new immigrants into sailing over.

What we do know is that it worked. People sailed in and by the mid-12th century, Greenland could boast two major towns, a population of several thousand, and even its own bishop. This rapid ascent was followed by a dizzying drop: by the 15th century, Greenland was virtually devoid of Norsemen, ruins of their settlements peeking out of snow across the land.

How these colonies developed and declined so fast has long fascinated historians. One theory proposed that a change in climate patterns, coupled with antiquated farming technology, made it impossible for the Greenland Norse to feed their population — so they left. One other holds that the Greenland Norse never really farmed much, but sustained their population by trading commodities with Europe. Walrus tusks were a particularly sought-after commodity in the time, and Erik’s frozen island was rich in walruses. When trade declined, the Norse also faded into history.

Walrus upper jaw bone.

A walrus rostrum (upper jaw bone) with tusks that was used in the study. Dated to c.1200-1400 CE based on the characteristics of a runic inscription in Old Norse.
Image courtesy of Musées du Mans.

This latter hypothesis is further supported by archeological findings in Europe. We’ve found many luxury items — from crucifixes to game pieces — fashioned out of walrus ivory in Europe around this time. However, the theory couldn’t be proved or disproved, as the source of this ivory couldn’t be pinpointed.

New research from the universities of Cambridge and Oslo, however, successfully established the source of this walrus ivory. By studying the DNA in walrus tusks and skulls from ivory workshops across the continent, the team found that Greenland held a “near monopoly” of the ivory supply in Western Europe for over two centuries. The research also revealed an evolutionary split in the walrus, allowing the team to distinguish between ivory sourced from Greenland and that obtained elsewhere.

Tusky business

The team worked with samples of walrus bone and tusk obtained from key medieval trading centers such as Trondheim, Bergen, Oslo, Dublin, London, Schleswig, and Sigtuna, dating between 900 and 1400 CE.

Ecclesiastical walrus ivory plaque.

Ecclesiastical walrus ivory plaque from the beginning of the medieval walrus ivory trade; believed to date from the 10th or 11th century. Found in North Elmham, Norfolk, UK.
Image credits Museum of Archaeology and Anthropology / University of Cambridge.

The tusks were exported still attached to the walrus’ skull. They helped protect the ivory during shipping and was later broken up at each workshop. The team extracted DNA from the remains of this process, as to avoid damaging any artifacts. Ivory was carved into luxury goods such as religious objects and game pieces.

DNA analysis revealed that the walrus branched into two lines during the last Ice Age — which researchers term “eastern” and “western”. The eastern lineage spread across much of the Arctic, while the western lineage remained contained in the waters between Canada and Greenland.

The lion’s share of walruses during the early years of the ivory trade came from the eastern lineage, the team reports. As demand soared from the 12th century onwards, however, the supply shifted almost entirely to tusks from the western lineage — namely, from walruses in Greenland. The Norse settlers there either hunted the animals themselves or traded with indigenous populations for the tusks, according to the team.

“The results suggest that by the 1100s Greenland had become the main supplier of walrus ivory to Western Europe — a near monopoly even,” says paper co-author Dr James H. Barrett. “The change in the ivory trade coincides with the flourishing of the Norse settlements on Greenland. The populations grew and elaborate churches were constructed.”

“Later Icelandic accounts suggest that in the 1120s, Greenlanders used walrus ivory to secure the right to their own bishopric from the king of Norway. Tusks were also used to pay tithes to the church,” he explains.

Europe was faring pretty well from the 11th to the 13th century, and demand for luxury and exotic goods soared. The Greenland Norse cashed in on this, supplying almost all of the ivory in Western Europe during this time. However, craftsmen eventually switched over to elephant ivory — there is virtually no evidence of walrus ivory imports in Europe past the year 1400, the team explains. Left without a market for their single most important export good, the Greenlanders’ economy ground to a halt.

“Changing tastes could have led to a decline in the walrus ivory market of the Middle Ages,” Barrett explains.

“An overreliance on a single commodity, the very thing which gave the society its initial resilience, may have also contained the seeds of its vulnerability.”

There may have been other factors at work, however. Walrus populations are known to abandon their coastal haulouts due to overhunting. The 14th century also saw the “Little Ice Age“, a sustained period of low temperatures. Finally, Europe was also going through some tough times, as the Black Death plagued the lands.

“Until now, there was no quantitative data to support the story about walrus ivory from Greenland,” says co-author Dr Bastiaan Star of the University of Oslo.

“Walruses could have been hunted in the north of Russia, and perhaps even in Arctic Norway at that time. Our research now proves beyond doubt that much of the ivory traded to Europe during the Middle Ages really did come from Greenland.”

The paper “Ancient DNA reveals the chronology of walrus ivory trade from Norse Greenland” has been published in the journal Proceedings of the Royal Society B: Biological Sciences.

Coho spawning.

Greenland, Faroe Islands to stop commercial fishing of wild salmon for 12 years

Greenland and the Faroe Islands will completely stop commercial wild salmon fishing for the next 12 years. The move aims to allow the species to regenerate and return to rivers in Canada, the United States, and Europe.

Coho spawning.

Coho spawning on the Salmon River, Idaho.
Image credits Bureau of Land Management Oregon and Washington / Flickr.

It seems that one of the worst qualities an organism can have in the twenty-first century is being tasty. Case in point: wild salmon. While there are several wild species belonging to the family Salmonidae, nine of them are commercially-important — and they aren’t faring very well at all. Overfishing has left wild populations on the brink of collapse, with potentially disastrous consequences both on an environmental as well as economic and social level.

Teach a man not to fish

In an effort to allow Atlantic populations some time to recover, the Atlantic Salmon Federation and North Atlantic Salmon Fund have convinced Greenland and the Faroe Islands to stop commercial salmon fishing for the next 12 years. These two countries were selected as their coastal waters hold feeding grounds that are crucial for wild salmon, harboring many individuals from endangered populations in rivers like Saint John in New Brunswick and the Penobscot in Maine.

In exchange, the two organizations have pledged financial support for alternative economic development in Greenland, scientific research, and education projects focused on marine conservation.

For now, the exact details of this financial agreement are being kept confidential — but the Atlantic Salmon Federation is adamant that not government money will be involved. All funding will be raised by the two organizations or will come from private donations.

Greenland fishermen will also be allowed catches up to 20 metric tonnes per year for personal and family consumption only. Even so, the deal is estimated to allow over 11,000 mature salmon to return to home rivers in 2019 instead of ending up in a net.

And nothing sums up why we need to do this better than this somewhat obvious but very valid observation of Chad Pike, chairman of the North Atlantic Salmon Fund:

“The best way to save North Atlantic salmon is to stop killing them,” he told The Globe and Mail. “This deal does that in meaningful numbers.”

“Significantly reducing the harvest of wild Atlantic salmon on their ocean feeding grounds is meaningful and decisive,” adds Bill Taylor, president of the Atlantic Salmon Federation.

Wild salmon stocks have steadily dropped to alarming levels in the past few years, caught between overfishing, ecosystem shifts caused by climate change, and other run-of-the-mill human meddling. Stocks have dwindled from roughly 1.8 million individuals returning on salmon runs in North America in the 1970s and ’80s to under 418,000 individuals in 1990, and the sustained efforts of the Atlantic Salmon Federation (about which you can read more here) have managed to prop up their numbers to roughly 600,000 in recent years.

Still, the situation is far, far from improving. Salmon runs across the US are at an all-time low: in California, Oregon, Idaho, Washington, and southern British Columbia, many bring less than 10% of their historical numbers. Others have simply stopped happening altogether, according to this paper by Robert T. Lackey from the Department of Fisheries and Wildlife. This paragraph puts how dire the state of wild Atlantic salmon is today into chilling perspective:

“Every few years, there is a media celebration of ‘record’ salmon runs, but these temporary blips are due mainly to favorable ocean conditions coupled with a recalibration of what constitutes a ‘record’ run. If doubling a run from 2% to 4% of the historical level qualifies as a record run, then we are often there, however modest the increase may be,” he writes.

“More sobering, the majority of such runs are usually hatchery-bred fish. Nowadays wild salmon comprise less than a quarter of many West Coast salmon runs.”

Delegations from Greenland and the Faroe Islands will declare the zero commercial quotas at next month’s international summit in Portland, Maine, which will work retroactively to April 30.

The 12-year moratorium should cover two whole generations of wild Atlantic salmon, allowing them to reproduce in peace. Both organizations, as well as officials from the two countries, expect that this will help significantly raise population numbers in the long term.