Pine Island is Antarctica’s biggest glacier and also the fastest melting one on the continent, responsible for about 25% of its total ice loss. Now, in a new study, researchers showed that the glacier is more vulnerable to rapid melting than previously thought, as climate change is weakening its natural braking system.
Together with its neighboring Thwaites glacier, Pine Island connects the center of the western Antarctic ice sheet with the ocean, discharging significant amounts of ice to the sea. These two glaciers have been losing ice for the past 25 years. If this speeds up, global seas could rise significantly over the next few centuries, scientists estimate.
“We may not have the luxury of waiting for slow changes on Pine Island; things could actually go much quicker than expected,” lead author Ian Joughin, said in a statement. “The processes we’d been studying in this region were leading to an irreversible collapse, but at a fairly measured pace. Things could be much more abrupt if we lose the rest of that ice shelf.”
The Pine Island and Thwaites glaciers have been under the spotlight in recent decades as their ice shelves thinned because warmer ocean currents melted the ice’s underside. Pine Island Glacier’s motion toward the sea accelerated from 2.5 kilometers per year in the 1990s to 4 kilometers per year to 2009. The speed then stabilized for almost a decade but is now accelerating.
Pine Island’s ice shelf lost one-fifth of its area in a few dramatic breaks from 2017 to 2020, captured by the Copernicus Sentinel-1 satellites, operated by the European Space Agency. This created icebergs more than eight kilometers long and 36 kilometers wide, which then split into lots of little pieces, Joughin told Associated Press.
Alongside scientists from the University of Washington and British Antarctic Survey, Joughin combined satellite data with a computer model of ice movement to determine what is driving the speed up. Due to its extremely remote location, satellites play a fundamental role in the measurement and monitoring of Antarctic glaciology.
The researchers found that the glacier’s ice shelf has retreated by 20 kilometers between 2017 and 2020. This was caught on time-lapse video from a European satellite that takes pictures every six days. The ice shelf seems to be “ripping itself apart” because of the glacier’s acceleration in the past two decades, Joughin explained.
“The recent changes in speed are not due to melt-driven thinning; instead they’re due to the loss of the outer part of the ice shelf,” Joughin said in a statement. “The glacier’s speedup is not catastrophic at this point. But if the rest of that ice shelf breaks up and goes away then this glacier could speed up quite a lot.
For the researchers, it’s not clear yet whether the shelf will continue to crumble or no, as other factors, such as the slope of the land below the glacier’s receding edge, will also influence the outcome. But what’s certain is that the new findings change the timeline for when Pine Island’s ice shelf could disappear and the speed the glacier might move.
The rate at which glaciers are melting has been steadily picking up according to a new study, based on satellite data. They’re now losing 31% more mass every year than they were just 15 years ago. The cause is anthropogenic climate change, the authors explain.
The study is based on 20 years’ worth of declassified three-dimensional satellite data. Based on these measurements, the authors estimated that mountain glaciers worldwide have been losing in excess of 328 billion tons (298 billion metric tons) of snow and ice per year every year since 2015. This is 78 billion tons (71 billion metric tons) a year more than the average between 2000 and 2004.
Half of the world’s glacial loss today is coming from the United States and Canada, the paper adds.
In addition to more ice being lost per year, global glacial thinning rates (another important indicator of glacier health) have also doubled in the last 20 years.
Virtually all of the world’s glaciers are affected, the team explains, even ones that were traditionally considered stable, such as those in Tibet. The precious few exceptions to this rule include a couple of glaciers in Iceland and Scandinavia, kept stable by increased levels of precipitation. But overall, global melt rates have been and still are accelerating. Alaska has the single highest overall melt rate seen in the study.
Melting rates are increasing quite uniformly across the world, a process that “mirrors the global increase in temperature” says Romain Hugonnet, a glaciologist at ETH Zurich and the University of Toulouse in France, who led the study. The cause, ultimately, is our growing use of fossil fuels such as coal, oil, and gas, which release greenhouse gases in the atmosphere.
The study’s findings are particularly worrying as this is the first paper to use 3D satellite imagery to examine all of Earth’s glaciers, not just those that are part of the Greenland or Antarctic ice sheets.
Not only are such results a chilling account of how deeply climate change is impacting glaciers and the world as a whole, but it also points to massive problems-to-be. Glaciers supply millions of people with their daily water needs, and them shrinking so quickly means that a lot of people will soon be in need to secure new sources of water. On the other end of the spectrum, rapid glacier shrinking increases the risk of events such as outburst floods from glacial lakes.
And, ultimately, all these glaciers melting around us have to flow somewhere — which is the ocean. Sea level rise is a very real problem that’s poised to cause us some massive issues in the future. Sea levels are already rising today, partially because of melting in glaciers and ice sheets, partially because higher mean temperatures make water expand in volume. Even so, today, glacier melt is responsible for an estimated 21% of the overall sea-level change we’ve recorded. Although the ice sheets hold overall more water and are thus the greater long-term threat, mountain glaciers hold a respectable amount of water and should not be overlooked in this regard.
Shrinking glaciers are a problem for millions of people who rely on seasonal glacial melt for daily water and rapid melting can cause deadly outbursts from glacial lakes in places like India, Hugonnet said.
But the largest threat is sea level rise. The world’s oceans are already rising because warm water expands and because of melting ice sheets in Greenland and Antarctica, but glaciers are responsible for 21% of sea level rise, more than the ice sheets, the study said. The ice sheets are larger longer term threats for sea level rise.
“It’s becoming increasingly clear that sea level rise is going to be a bigger and bigger problem as we move through the 21st century,” said National Snow and Ice Data Center Director Mark Serreze.
The paper “Accelerated global glacier mass loss in the early twenty-first century” has been published in the journal Nature.
New research at the Monash University reports that historic ice loss in Antarctica has persisted for several centuries after it first started.
Such findings underscore the inertia of processes affecting ice sheets and suggest that today’s polar ice will continue to shrink for quite a long time even if climate change is avoided.
“Our study implies that ice loss unfolding in Antarctica today is likely to continue unabated for a long time—even if climate change is brought under control,” said lead study authors Dr. Richard Jones and Dr. Ross Whitmore, from the Monash University School of Earth, Atmosphere and Environment.
The study charts the extent of ice in the Mawson Glacier, which is adjacent to a region of the Ross Sea that saw a rapid retreat of sea ice after the Last Glacial Maximum.
According to the team, this area experienced at least 220 meters of abrupt ice thinning between 7,500 and 4,500 years ago, and more gradual thinning up until a thousand years ago. The same abrupt ice loss has occurred (at similar rates) in other glaciers formed on various bed topographies across multiple regions during the mid-Holocene, they explain. The Holocene is the current geological epoch.
Sea-level and ocean temperature data suggest that warmer oceans were the key drivers of this ice loss. Warmer waters most likely hastened glacier retreat (through ground-line melting, which makes glaciers slip more quickly into the oceans) which led to greater sheet instability and faster melting.
“We show that part of the Antarctic Ice Sheet experienced rapid ice loss in the recent geological past,” said Professor Andrew Mackintosh, head of the Monash School of Earth, Atmosphere, and Environment, and co-author of the paper.
“This ice loss occurred at a rate similar to that being observed in rapidly changing parts of Antarctica today, and it was caused by the same processes that are considered to cause current and probable future Antarctic ice mass loss—ocean warming, amplified by internal feedbacks.”
This retreat continued for several centuries after it first started, the authors note, which gives us cause to believe that the ice loss we’re seeing today will behave similarly. Such findings are particularly troubling in the context of climate change, which is driving glacier ice loss through higher atmospheric and ocean mean temperatures.
In another sign of the acceleration of global warming, ice in the Arctic Ocean has melted to its second-lowest level on record this year. The Floes glacier shrunk to 3.74 million square kilometers (1.4 million square miles) last week, according to preliminary data from satellite observation.
The only other time such a low level was seen was in 2012 when the ice pack was reduced to 3.41 million square kilometers after a late-season cyclonic storm. Arctic sea ice usually reaches its low point in September, but it’s melting more and more each year as the polar north warms due to climate change.
“It’s been a crazy year up north, with sea ice at a near-record low… heat waves in Siberia, and massive forest fires,” said Mark Serreze, director of the National Snow and Ice Data Center (NSIDC), in a statement. “The year 2020 will stand as an exclamation point on the downward trend in Arctic sea ice extent. We are headed towards a seasonally ice-free Arctic Ocean, and this year is another nail in the coffin.”
This year’s drop in sea ice levels was particularly sharp between August 31 and September 5 due to pulses of warm air from a heatwave in Siberia, according to the NSIDC. The rate of ice loss during those six days was greater than during any other year on record, with temperatures in the Siberian Arctic 8ºC to 10ºC (14 to 18 Fahrenheit) above normal.
Studies have shown the warming of the Arctic and the melting of sea ice is influencing weather further south, altering the jet stream that powers the weather system. As ice disappears, it leaves areas of dark water open, which absorb radiation instead of reflecting it back to the atmosphere. This amplifies global warming and explains why the Arctic is warming faster than the rest of the world.
The reduction on sea ice levels in the Arctic is threatening wildlife, from seals and polar bears to algae, said Tom Foreman, a polar wildlife expert, for Al Jazeera.
“The numbers that we’re getting in terms of the extent of sea ice decrease each year put us pretty much on red alert in terms of the level of worry that we have, our concern for the stability of this environment,” he explains.
A study earlier this month discovered that the Arctic sea ice has melted so much in the last few decades that even a record cold year won’t produce the amount of summer sea ice that existed in the mid-20th century. High air temperatures during autumn and winter will drive the region to a district climate by the middle of this century, they found.
At the same time, Hamburg University scientists found in a study last April that by 2050 the North Pole would be ice-free in some Arctic summers. Every ton of carbon dioxide emitted worldwide led to three square meters of ice melt in the highly sensitive Arctic, said the study’s lead earth scientist Dirk Notz.
Countries agreed to limit global temperature rises to “well below” 2ºC (3.6 degrees Fahrenheit) through the Paris Agreement signed in 2015. But greenhouse gas emissions are still going up, with more ambitious climate action needed. The drops in emissions from the pandemic haven’t had a significant effect on climate change, and lockdowns are being lifted around the world.
The Earth has lost 28 trillion tons of ice between 1994 and 2017, a group of United Kingdom researchers found based on satellite surveys of glaciers, mountains, and ice sheets. This could cause sea levels rise to steeply increase, possibly reaching a meter (three feet) by the end of the century.
Based at Leeds and Edinburgh universities and University College London, the researchers described the level of ice loss as “staggering” and warned that the melting of the ice is reducing the planet’s ability to reflect solar radiation back into space (albedo). As ice disappears, the soil is absorbing more heat and warming the planet.
But that’s not it. Ecosystems in the Arctic and Antarctic waters are being disrupted by cold freshwater pouring from glaciers and ice sheets. Meanwhile, the loss of glaciers located in mountain ranges could mean the loss of fresh water sources on which many communities rely on across the world.
“In the past researchers have studied individual areas – such as the Antarctic or Greenland – where ice is melting. But this is the first time anyone has looked at all the ice that is disappearing from the entire planet,” co-author Andrew Shepherd told The Guardian.
“What we have found has stunned us.”
Arctic sea ice (7.6 trillion tons), Antarctic ice shelves (6.5 trillion tons), mountain glaciers (6.2 trillion tons), the Greenland ice sheet (3.8 trillion tons), the Antarctic ice sheet (2.5 trillion tonnes), and Southern Ocean sea ice (0.9 trillion tons) have all decreased in mass, the study found.
Up to 60% of the ice loss was from the northern hemisphere, and the remainder was from the southern hemisphere. The rate of ice loss has risen by 57% since the 1990s – from 0.8 to 1.2 trillion tones per year – owing to increased losses from mountain glaciers, Antarctica, Greenland, and from Antarctic ice shelves.
The majority of all ice loss was driven by atmospheric melting (68% from Arctic sea ice, mountain glaciers ice shelf calving, and ice sheet surface mass balance), with the remaining losses (32% from ice sheet discharge and ice shelf thinning) being driven by oceanic melting.
“To put the losses we’ve already experienced into context, 28 trillion tonnes of ice would cover the entire surface of the UK with a sheet of frozen water that is 100 metres thick,” group member Tom Slater from Leeds University told The Guardian. “It’s just mind-blowing.”
The researchers argued there’s “little doubt” that climate change is behind the staggering losses. They note that the planetary surface temperature has already grown by 0.85ºC since 1880 and that this has been amplified in the polar regions. Sea and atmospheric temperatures have risen as a result, triggering the ice losses.
The findings come a week after researchers found in another study that Greenland’s ice sheet, the world’s second-largest ice body, might have passed a point of no return. The snowfall that replenishes the country’s glaciers every year can’t keep up with the pace of the ice melt, meaning the ice sheet will lose ice even if temperatures stop rising.
New Zealand is running out of ice, a new study finds. Glaciers in the country’s Southern Alps have lost around 77% of their maximum volume, which was reached around 400 years ago (at the end of the Little Ice Age).
The team also found that the rate of loss has doubled since that time, promoted by man-made climate change. In absolute terms, these glaciers have lost more ice than they still retain today.
Such a development is worrying not only from a global level — mountain glacier and ice cap melt account for around 25% of sea-level rise — but also for local communities and ecosystems. Glacier melt is often a key resource for plants, animals, and humans living downstream, providing irrigation, drinking water, and powering dams.
“These findings quantify a trend in New Zealand’s ice loss. The acceleration in the rate of ice mass loss may only get worse as not only climate but also other local effects become more pronounced, such as more debris accumulating on glaciers surfaces and lakes at the bottom of glaciers swell, exacerbating melt,” says Dr. Jonathan Carrivick, from the University of Leeds’ School of Geography, lead author of the study.
The study determined the changes in volume experienced by 400 mountain glaciers across New Zealand’s Southern Alps for three time periods; the pre-industrial Little Ice Age to 1978, from 1978 to 2009, and from 2009 to 2019. These volumes were estimated using historical records of the glaciers’ outlines, and from the local distribution of moraines and trimlines (bodies of debris and clear lines created by glaciers as they move across the landscape).
Moraines and trimlines are reliable indicators of a glacier’s extent, and can be used to chart changes in their size over time.
Comparing glacier surface during the Little Ice Age and that in more recent times, the team found that ice loss increased twofold since the Little Ice Age, with most of that increase being concentrated in the last 40 years.
Around 17% of the ice volume present in the Little Ice Age was lost between 1978 and 2019. This left only 12% of the initial ice mass after 2019, most of it in low-altitude areas of the original glaciers (the ‘ablation zone’).
“Our results suggest that the Southern Alps has probably already passed the time of ‘peak water’ or the tipping point of glacier melt supply,” adds Carrivick.
“Looking forwards, planning must be made for mitigating the decreased runoff to glacier-fed rivers because that affects local water availability, landscape stability and aquatic ecosystems.”
All in all, the research shows that even the most ancient glaciers on the planet are buckling under climate change. Furthermore, they show that the destruction of such glaciers “has dramatically worsened since 2010,” according to co-author Dr. Andrew Lorrey.
The research comes as yet another alarm that not all is well on the planet, and that the problem is our emissions. Researchers have been urging for action in this area but, so far, policymakers have only engaged in modest efforts for change.
Sooner or later, these issues will start affecting each and every one of us directly — by impacting our wealth, our health, and our access to vital resources like food or water. And by then, it will be too late to fix them in our lifetimes, perhaps even in our children’s lifetimes.
The paper “Ice thickness and volume changes across the Southern Alps, New Zealand, from the little ice age to present” has been published in the journal Scientific Reports.
A paper published back in 2017 estimated that the St. Patrick Bay ice caps in Canada would disappear in 5 years due to climate change. We’re barely halfway through that time, and they’ve already melted.
NASA imagery shows that the ice caps have melted far faster than scientists predicted — 3 years instead of 5. That initial estimation was made by scientists from the National Snow and Ice Data Centre (NSIDC) at the University of Colorado Boulder in 2017.
The melting of these caps should be a very clear warning that climate warming is picking up around the world, and shows the dangers of officials choosing to ignore or confound science consensus.
Melt rate — fast
The ice sheets spread over more than 10 square kilometers (around 4 sq miles) in total back in 1950. Mark Serreze, a geographer, NSIDC director, and lead author of the 2017 paper, remembers the striking view when he visited the area in 1982.
“When I first visited those ice caps, they seemed like such a permanent fixture of the landscape,” says geographer and NSIDC director Mark Serreze. “To watch them die in less than 40 years just blows me away.”
By the time Serreze started writing the paper, these ice sheets were only 5% of the size they were in 1959. Today, satellite images from NASA’s Terra satellite shows that no trace of this ice remains — and with the way things are progressing, it won’t be back in the foreseeable future.
The ice caps are part of a larger body of ice sheets in the Hazen Plateau on Ellesmere Island. This land stretches well into the Arctic and is one of the most northerly points in all of Canada. Two other glaciers that would often link with the now-melted pair, the Murray and Simmons ice caps, are faring better due to their high altitude. However, researchers think these two will also collapse soon, as their size was at 39% and 25%, respectively, of what they were in 1959.
One thing I find particularly heartbreaking about this story is that Serreze and his team first started work in the Hazen Plateau around 1980 as they were trying to understand whether human activity was causing climate change. At the time, scientific consensus was not yet established on the issue, and some research suggested we were actually going through a period of global cooling (at least publicly — Shell knew).
So one of the sites that helped us prove once and for all that the way we do things is hurting the planet has been destroyed exactly because of that damage.
But it’s also a sobering wake-up call that the climate isn’t changing in the future — it’s changing right now.
“We’ve long known that as climate change takes hold, the effects would be especially pronounced in the Arctic,” says Serreze. “But the death of those two little caps that I once knew so well has made climate change very personal. All that’s left are some photographs and a lot of memories.”
Scientists had been waiting and watching it for months and it finally happened. A 300 square kilometers (116 square miles) iceberg broke off Pine Island Glacier (PIG), Antarctica’s biggest glacier and also the fastest melting one of the continent.
Thanks to the images of the European Space Agency’s (ESA) Sentinel satellites, last year two large cracks were detected in the glacier in 2019 and scientists have been closely monitoring the speed with which these cracks grow.
The cracks in the glacier expanded fast and eventually led to the splitting of the iceberg on February 9. It took just a day for the iceberg to divide into smaller pieces and one of them was large enough to be named, B-49, and tracked by the United States National Ice Centre.
An animation published by ESA used 57 radar images captured between February 2019 and February 2020 (the last one on February 10) and shows how fast the emerging cracks grew and led to this event.
“What is unsettling is that the daily data stream [from satellites] reveals the dramatic pace at which climate is redefining the face of Antarctica,” said Mark Drinkwater, senior scientist and cryosphere specialist at the European Space Agency, in a press release.
The Pine Island Glacier, together with its neighboring Thwaites Glacier, connects the center of the western Antarctic ice sheet with the ocean, discharging significant amounts of ice to the sea. These two glaciers have been losing ice for the past 25 years.
Due to its extremely remote location, satellites play a fundamental role in the measurement and monitoring of Antarctic glaciology, revealing the timing and pace of the withdrawal of glaciers in Antarctica. Since the early 1990s, the ice speed of the Pine Island glacier has increased dramatically to values exceeding 10 meters per day.
The floating ice front of Pine Island Glacier, which has an average thickness of approximately 500 meters, has undergone a series of detachment events in the past 30 years, some of which have abruptly changed the shape and position of the ice front.
“This indicates that Pine Island ice shelf is weakening as a result of warm ocean water and this is important as the ice in the Amundsen Sea Embayment, where PIG is located, is the area where we scientists are most worried about contributions to sea-level rise,” Stef Lhermitte, a remote sensing scientist from the Delft University of Technology in the Netherlands, said to ABC.
Western Antarctica is one of the regions of the world most affected by climate change and its collapse would mean a significant sea-level rise. A recent study showed that global warming changed the character of the winds that blow over the ocean near some of the glaciers, affecting them in severe ways.
The new development on the Pine Island Glacier happened just a week after a temperature record of 18.3ºC was registered in Antarctica, exceeding the previous record of 17.5ºC. Temperatures in the white continent have been measured since 1961, with the historical minimum set at -89.2ºC in 1983.
Known as the “doomsday glacier”, the Thwaites Glacier in Antarctica is 74.000 square miles across and has been described as vulnerable to global warming.
A group of scientists decided to take a closer look and try to find out whether the glacier will soon collapse.
To say that Thwaits is suffering is an understatement. The amount of ice that has flown out of Thwaites as well as from other glaciers of the area has almost doubled over the past 30 years.
The ice that drains from Thwaites into the Amundsen Sea accounts for 4% of the global sea-level rise. If it collapses completely, it would increase sea levels around 65cm (25 inches).
That’s why scientists are now trying to find out how fast that could happen. Five teams of researchers from the US and UK have been working in Thwaites for the past two months. They have drilled the glacier for the first time between 300 and 700 meters through the ice to the ocean, extracting cores to find out more information about the glacier’s history and future evolution.
“We know that warmer ocean waters are eroding many of West Antarctica’s glaciers, but we’re particularly concerned about Thwaites. This new data will provide a new perspective of the processes taking place so we can predict future change with more certainty,” said Keith Nicholls, an oceanographer from the UK.
The teams used a set of instruments at the grounding zone, feeding them through the borehole. This included a small under-ice robot called Icefin that collected data on the interaction of the glacier with the ocean and the underlying sediments.
Icefin swam two kilometers in January from the drill site to the Thwaites grounding zone and measured, took images and mapped the melting and the dynamics of the glacier. Meanwhile, another team extracted sediments through a metal tube that made holes in the ice.
“We designed Icefin to be able to access the grounding zones of glaciers, places where observations have been nearly impossible, but where rapid change is taking place. To have the chance to do this at Thwaites Glacier, which is such a critical hinge point in West Antarctica, is a dream come true,” said Britney Schmidt, lead scientist for Icefin.
More than 100 scientists and support staff are taking part in the field season on the Thwaites Glacier, located 1600 kilometers away from the UK and the UK stations. The main goal is to improve predictions on the global sea-level rise from Thwaites through a better understanding of the dynamics of the ice sheet.
The research teams started their work in Antarctica in November 2019 and will be there until March. Most of the researchers travel through the US station, then going to the camps located near the Antarctic coast. Teams are located at an already existing camp on the ice called West Antarctic Ice Sheet Divide.
UK science minister Chris Skidmore said: “This is an exciting achievement by our researchers. We are leading the fight against climate change and UK researchers are at the forefront of investigating the impact of rising temperatures in Antarctica. The government is making significant investments toward their vital work.”
Earth’s oldest glacial ice is located in the Tibetan Plateau of China. For over 15,000 years, it has been the host of a group of frozen viruses, most of them unknown until now.
Researchers have now discovered the viruses and warned that as climate change continues to melt more and more ice, more pathogens could also emerge.
The team analyzed two ice cores from the Tibetan glacier, unveiling the presence of 28 previously unknown virus groups. Investigating them will be key to learn which viruses have developed in different climates over time, researchers argued in their paper on server bioRxiv.
“The microbes differed significantly across the two ice cores, presumably representing the very different climate conditions at the time of deposition that is similar to findings in other cores,” the researchers wrote, claiming the experiment will help to establish a baseline for glacier viruses.
Sampling ice cores is no easy feat. You not only have to do it in the right conditions to ensure that the ice is unaffected, but you also have to ensure that no contamination is caused.
The team created a protocol for ultraclean microbial and viral sampling, applying it to two preserved ice core samples from 1992 and 2015. These cores were not handled in a way that prevents contamination during drilling, handling and transportation — which means that the exterior of the ice was most likely contaminated. In order to avoid this effect, researchers only analyzed the inside of the core, which was presumed to be unaffected.
The team worked in a cold room at minus 5 degrees Celsius (23 degrees Fahrenheit) to access the inner part of the cores, using a saw to cut 0.2 inches (0.5 centimeters) of ice from the outside later.
Then, the team used ethanol to wash and melt another 0.2 inches of ice and then sterile water to wash another 0.2 inches. This allowed them to access the inner layer to do their study, having in total shaved off about 0.6 inches or 1.5 centimeters of ice of the sample.
A total of 33 groups of viruses were found in the ice cores, of which 28 were completely new to science. “The microbes differed significantly across the two ice cores,” the researchers wrote, “presumably representing the very different climate conditions at the time of deposition.”
The growing temperatures of the world because of climate change is melting glaciers across the planet, so these viral archives could soon be lost, the researchers said. But that’s not the only bad news, as the ice melt could challenge our ability to stay safe from them.
“At a minimum, [ice melt] could lead to the loss of microbial and viral archives that could be diagnostic and informative of past Earth climate regimes,” they wrote. “However, in a worst-case scenario, this ice melt could release pathogens into the environment.”
Measuring ice melt and the unprecedented changes in our cryosphere – the frozen parts of the planet which regulate the climate by reflecting the sun’s heat – is crucial for understanding future situations, he says.
We spoke to Prof. Kääb about the importance of the cryosphere and what we know about how it’s changing.
Why is the cryosphere important?
‘The cryosphere – that is glaciers and ice sheets, snow, sea ice, permafrost, and lake and river ice – and changes of the cryosphere affect the lives of hundreds (of) millions (of people) and many ecosystems in various direct and indirect ways. Seasonal or year-round snow covers around 45 million sq km, and glaciers and the Greenland and Antarctic ice sheets an additional 15 million sq km, together (constituting) around 40% of the Earth’s land area.
‘Importantly, most ice on Earth is very close to melting conditions, a few degrees below 0°C, and thus reacts very sensitively to changes in air temperatures. Small temperature changes can trigger melt and (large) environmental changes. Sea level change through increased melt of glaciers and ice sheets is certainly the most far-reaching effect of ice melt on Earth.’
How are sea levels changing?
‘Melting of glaciers, (and) the two ice sheets in Greenland and Antarctica contributes to more than half of the currently measured sea level rise and they are projected to contribute more. The other half is thermal expansion – as the ocean gets warmer it expands – and all this sea level change affects people around the world, especially in coastal areas, (and) even if living far away from the melting ice.
‘Mean sea level is projected to rise about 1 metre by 2100 and will threaten coastal societies. How much the ocean would rise in (the) case of an, unrealistic, complete melt of the Antarctic ice sheet is around 60m.’
What are the other impacts of ice melt?
‘In terms of more local effects, there are a number of hazards relating to glaciers and thawing permafrost that we expect to increase. For instance, if glaciers retreat they leave steep mountain flanks uncovered so there is debris and rocks that are set to destabilise. So, we expect more rockfalls or debris flows from such areas.
‘Greenhouse gas emissions from thawing permafrost are much less understood, but could have an equally wide, actually global, impact by enhancing manmade emissions.
‘Then there are also hazard situations that could actually improve. (Ice avalanches from glaciers) can destroy infrastructure, houses and kill people. But (there’s) the extreme case (where) if a glacier retreats very much, then the hazard from related ice avalanches could actually reduce.’
Do you think we have passed a tipping point when it comes to ice melt?
‘The term tipping point is a bit controversial, because in most cases we don’t really know. Another term that is better is what the IPCC (International Panel on Climate Change) uses – committed (climate) change. So, climate change that man has contributed to has committed changes to the future.
‘That means the excess energy that mankind has already caused (through greenhouse gas emissions capturing the sun’s heat) will commit a long-term change in glaciers, ice sheets and ocean temperatures. Change that, let’s say, over a hundred years is irreversible. Even if we change our emissions now, a lot of ice melting has been committed.’
‘Glaciers are typically found comparably close to where people live. That means their changes affect people quite directly.’
Professor Andreas Kääb, University of Oslo, Norway.
You focus on glaciers. Why do we need to understand glacier change?
‘Glaciers are typically found comparably close to where people live. That means their changes affect people quite directly. Understanding glacier change helps to adapt to related climate change impacts such as changes in dry-season run-off and water supply, changes in glacial landslides and avalanches, or changes in the touristic value of glaciers.
‘Glaciers reflect climate change in a very visible and clear way. Their shrinkage has become for good reason an icon of climate change. For scientists, glaciers are important to illustrate climate change and make it understandable for a large audience.’
You were the coordinator of ICEMASS, a project using satellite imagery to measure and analyse changes to glaciers. How did you analyse change?
‘We have increasingly more and more different satellite data, and what the satellites measure is very different. My main goal, my main achievement, of the ICEMASS project was actually bringing different data together and integrating them. For instance, we use optical satellite images repeatedly to measure glacier flow. This works perfectly fine unless you have cloud cover or polar night (24-hour darkness). Then we use radar images that penetrate through clouds for the same purpose. But this does not give us the volume of glaciers.
‘For that we use, among others, satellites that shoot laser beams, like your laser pointer, and they measure the return time of this signal. The signal is sent from a satellite, bounces (off) the glacier surface, and comes back to the satellite. The time difference is directly related to the distance from the satellite to the (glacier surface). So, if you know the satellite position very well, which we do, then you can measure the height. And if you do that, over time, repeatedly, you get also the changes in glacier thickness and volume.’
And what did you find?
‘For me, personally, the most important results are more regional scale results. We developed glacier volume changes over a number of areas where little was known before. One of the examples that made it into the Nature journal, for instance, was glacier volume changes over the Himalayas and Central Asia. There was a lot of different numbers around for these melting glaciers – some actually massively contradicted each other – from very little change to massive change. And we (really) narrowed this uncertainty down.’
What did your project reveal about the state of glaciers around the world?
‘We found glacier mass loss in almost all regions we looked at. Unexpected large losses we measured in the European Arctic, on Svalbard. The massive retreat of sea ice in this sector of the Arctic raises air temperatures at a rate of roughly double the global average. The result is glacier melt rates (that are) much higher than one would expect so far north. In addition, about half of the glacier mass loss comes not from direct glacier melt but from glaciers that massively increased their ice flow and thus their ice discharge into the ocean.
‘(We found) unexpected low changes in glacier mass, lower than the global average, in parts of Central Asia, in the Karakoram, Pamir, and western parts of Tibet. There is even a region where glaciers grow a little bit. By also measuring changes of lakes without direct river outflow, we could show that the region received in recent years more precipitation, which let the lakes and the glaciers grow, despite air temperatures increasing at the same time.’
This year’s IPCC Special Report on the Ocean and Cryosphere says climate change will cause up to 80% loss of glaciers in some places by the year 2100. What can research do to help society prepare for this future melting?
‘Carbon dioxide levels are much higher than they have been for the last 1 million years or more. This means our climate is at a stage where we don’t have historical experience to build sound statistics on extreme events. So, we need to monitor more what is going on now and then we need to better model future scenarios.
‘The EU has their own fleet of satellites, the Sentinels within the Copernicus programme. They are really a game changer because before them there were mostly occasional scientific satellites.
‘These EU satellite constellations, in my experience, help develop models and strategies for really long-term perspectives. (We need these) satellites to allow for the long-term, consistent, observations that we need to predict and adapt to climatic changes.’
This interview has been edited and condensed.
The research in this article was funded by the EU’s European Research Council. If you liked this article, please consider sharing it on social media.
We’re set on the path of rising sea levels, even if the pledges made for the Paris climate agreement are met and global temperatures stabilize, a new paper reports.
The Paris agreement on climate change mitigation was adopted in December 2015 and aims to limit the rise of global average temperatures to a maximum of 2°C compared to pre-industrial levels. The ideal scenario under the agreement would be to limit this figure to 1.5°C, and the countries that signed into the agreement are expected to make efforts towards this goal.
While a successful Paris agreement would do wonders for our efforts against climate heating and environmental degradation, we’re already set for rising sea levels around the world by 2300, a new study reports.
We’re already there
“Even if we were to meet these initial goals of the Paris agreement, the sea level commitment from global warming will be significant,” said Peter Clark, an Oregon State University climate scientist and a co-author of the study.
“When we pump more carbon into the atmosphere, the increase in temperature is almost immediate. But sea level rise takes a lot longer to respond to that warming. If you take an ice cube out of the freezer and put it on the sidewalk, it takes some time to melt. The bigger the ice cube, the longer it takes to melt.”
The authors say this is the first effort to quantify how sea levels will rise from carbon emissions (both past and future) released since the agreement was signed. In the first 15 years following the agreement, they report, will cause a rise of roughly 20 centimeters (7.9 in) by 2300. The estimate does not take into account the effect of irreversible melting in parts of the Antarctic ice sheet, the team adds, which is already underway.
A one-meter rise is expected by 2300, caused by emissions dating back to the year 1750. Around 20% of that rise can be traced back to emissions released since after the Paris agreement was signed. Around half of it (so 10% of the total projected rise) is attributable to the world’s top five polluters, the team found: the United States, China, India, Russia, and the European Union
Sea level rise is a huge threat to coastal ecosystems and human communities, with the potential to affect and/or displace hundreds of millions around the world (coastal areas are the most heavily-inhabited regions on Earth). Sea level rise is mostly driven by melt from glaciers and ice sheets draining into the ocean. But these are massive structures strewn all over the world, and they each respond to climate heating in their own time, ranging from decades to millennia.
“Much of the carbon dioxide we’ve emitted into the atmosphere will stay up there for thousands of years,” said Clark, who is on the faculty of OSU’s College of Earth, Ocean, and Atmospheric Sciences.
“So our carbon emissions this century are not only committing our planet to a warmer climate, but also to higher sea levels that will also persist for thousands of years.”
The paper “Attributing long-term sea-level rise to Paris Agreement emission pledges” has been published in the journal Proceedings of the National Academy of Sciences.
A part of the Mont Blanc glacier in Italy could collapse at any moment, Italian authorities warned, after closing roads and ordering the evacuation of huts on the side of the glacier.
A staggering 250,000 cubic meters (8.8 million cubic feet) of ice could break away from the Planpincieux glacier on the Grandes Jorasses mountain in the Mont Blanc massif, experts at the Valle d’Aosta regional government and the Fondazione Montagna Sicura (Safe Mountain Foundation) reported in an analysis.
While it’s impossible to predict the exact timing of the collapse, observations in August and September showed that the glacier was shifting at a speed of 50 to 60 centimeters (20 to 24 centimeters) a day, experts said.
“These phenomena once again show that the mountain is going through a phase of strong change due to climatic factors, therefore it is particularly vulnerable,” Stefano Miserocchi, mayor of nearby Courmayeur, said in a statement. “In this case, it’s a temperate glacier particularly sensitive to high temperatures.”
Miserocchi ordered the closure of roads in the Val Ferret valley and the evacuation of mountain huts in the Rochefort area, as precautionary measures. He added that a glacier collapse would not threaten residential areas or tourist facilities.
With 11 peaks above 4,000 meters (13,123 feet) between Italy and France, Mont Blanc is Western Europe’s highest mountain range and is popular with hikers, climbers, and skiers.
Alpine glaciers are melting as a result of rising global temperatures. According to the latest registry of glaciers, their surface area decreased from 609 square kilometers (235 square miles) in 1989 to 368 square kilometers (142 square miles) now — a fall of 40%.
Earlier this month, dozens of people took part in a “funeral march” to mark the disappearance of the Pizol glacier in north-east Switzerland. The glacier, in the Glarus Alps, has shrunk to a tiny fraction of its original size. Scientists say it has lost at least 80% of its volume just since 2006, a trend accelerated by rising global temperatures.
In a speech on climate change to the United Nations General Assembly in New York Tuesday, Italian Prime Minister Giuseppe Conte referred to the Mont Blanc warning.
“It is now news that a glacier on Mont Blanc risks collapsing,” he said. “It’s an alarm that cannot leave us indifferent. It must shake us all and mobilize us.”
Melting Antarctic icebergs can insulate the Southern Hemisphere from man-made climate change — for a while.
Image credits Luisella Planeta Leoni .
We’ve seen earlier today how climate heating impacts the stability of the Antarctic ice sheets — now let’s take a look at how it, in turn, impacts climate. New research from the University of Hawaii, Penn State University, the University of Massachusetts, and the IBS Center for Climate Physics (South Korea), states that the “iceberg effect” created by these melting ice sheets can “significantly” slow down human-induced warming in the Southern Hemisphere.
Not good, not terrible
“Our results demonstrate that the effect of Antarctic melting and icebergs needs to be included in computer model simulations of future climate change,” says Dr. Fabian Schloesser, lead author of the study.
“Climate models currently used in the 6th climate change assessment of the Intergovernmental Panel on Climate Change (IPCC) do not account for this process.”
Icebergs breaking off the Antarctic ice sheets can help delay the worst of climate change in the Southern Hemisphere, the team explains.
Recent observations regarding the rapid thinning of the Pine Island and Thwaites glacier regions in Antarctica (due to warmer oceans and climate-fueled shifts in wind patterns) raise concerns regarding an accelerated ice loss of the West Antarctic ice sheet. This also carries the scary prospect of rapid and significant sea-level rise.
Ice loss occurs either in the form of melt-induced (liquid) freshwater discharge into the ocean, or through (solid) iceberg calving. So part of the retreating ice sheet melts away, while the rest breaks off as icebergs. Putting two and two together, this means that we can expect to see more and more frequent iceberg discharge in the Antarctic.
Iceberg photographed in the Greenland Sea. Image credits Jerzy Strzelecki via Wikimedia.
Icebergs are huge things. They can persist for years at a time, floating along their merry way through the Southern Ocean until they reach warmer waters and melt. Now, since icebergs are just hefty chunks of ice, this also helps cool down ocean water as they go. Furthermore, freshwater discharge from icebergs impacts currents by lowering ocean salinity.
What the team set out to understand was whether this “iceberg effect” can delay or alter future climate change in the Southern Hemisphere. They ran a series of climate heating computer simulations, which include the combined freshwater and cooling effects of icebergs on the ocean, to quantify the effect of the icebergs on future climate in the area.
The researchers tweaked their model so that the size and number of icebergs it ‘releases’ mimics the gradual retreat of the Antarctic ice sheet over a period of several centuries. Then they simply switched the “iceberg effect” on and off to see what would happen. The results showed that the combined effect of those icebergs can significantly slow down man-made climate heating in the Southern Hemisphere, impacting global winds and rainfall patterns.
While all that ice can drain away a lot of heat it also comes with a caveat: sea level rise
“To melt the icebergs released over the 21st century in one of our extreme Antarctic ice-sheet retreat scenarios would require 400 times the current annual world energy consumption,” explains Dr. Tobias Friedrich, coauthor of the study.
“Global sea level would rise by about 80 cm, impacting many coastal regions and communities worldwide.”
The team explains that the iceberg effect largely compensates for the processes that were previously thought to accelerate Antarctic melting.
“Our research highlights the role of icebergs in global climate change and sea level rise,” says Prof. Axel Timmermann, corresponding author of the study and Director of the IBS Center for Climate Physics.
“Depending on how quickly the West Antarctic ice sheet disintegrates, the iceberg effect can delay future warming in cities such as Buenos Aires and Cape Town by 10-50 years.”
The research team plans to further analyze the interplay between ice, climate, and global sea level with a new computer model that they developed.
The paper “Antarctic iceberg impacts on future Southern Hemisphere climate” has been published in the journal Nature Climate Change.
Global heating is exposing the Himalayas to pollutants trapped in glacier ice.
Image credits: Sharada Prasad.
The world still has a lot of work to do when it comes to regulating pesticide usage, but a few decades ago, things were much worse. According to a new study, harmful chemicals used in pesticides have been accumulating in the ice sheets and glaciers since the 1940s. Now, those chemicals are being released into the environment as the climate continues to heat up.
Pollutants can travel long distances and accumulate even in the most pristine environments. Previous studies have shown that they can travel for thousands of kilometers before being incorporated into Arctic or Antarctic ice (or glaciers) — where they remain trapped. This phenomenon makes it so that, paradoxically, pristine areas close to the poles are more polluted than other areas closer to the pollution source. This is called the Arctic paradox.
The paradox is also applicable to high mountain glaciers in the Himalaya.
South Asia, which hosts much of the Tibetan and Himalayan regions, features some of the most heavily-polluted areas in the world. It also hosts numerous glaciers.
The Nam Co Basin, on the central Tibetan Plateau, is home to more than 300 glaciers. These glaciers are melting at a rate that is unprecedented in human history. Between 1999 and 2015, the total volume of ice in the Nam Co Basin decreased by nearly 20%. This is not only putting people’s water supplies at great risk, but is also releasing significant quantities of dangerous chemicals into the environment, says Xiaoping Wang, a geochemist at the Chinese Academy of Sciences and an author on the new study.
Wang and colleagues measured the concentrations of a class of chemicals used in pesticides called perfluoroalkyl acids (PFAAs) in glacial ice and snow, meltwater runoff, rain and lake water in Nam Co Basin. They found that the glaciers in the region are a source of PFAA pollution, which they are slowly releasing into lake Nam Co. Each glacier is releasing PFAAs at a rate of over 1 milligram per day, which amounts to approximately 1.81 kilograms per year.
“In general, the results are comparable to previous studies on lakes in polar regions,” the team wrote, emphasizing the similarities to the Arctic paradox.
While the quantities are not huge, PFAAs have a very long lifespan, they don’t biodegrade, and are passed along the food chain and through various biogeochemical processes. The ones to suffer the effects first are microorganisms, and then insects. As different predators eat them, they absorb higher and higher pollutant quantities.
While this study did not include a toxicity risk assessment for aquatic life, previous research suggests that eating fish from the polluted lake would be unsafe for human health. Furthermore, the Nam Co Basin also feeds directly into water resources in India, which could mean even more hazards down the line.
The high mountain glaciers of the Tibetan Plateau feed thousands of alpine lakes that form the headwaters of many of Asia’s major rivers. Credit: NASA, Jeff Schmaltz, MODIS Rapid Response Team, Goddard Space Flight Center.
More importantly, the study underlines once again just how interconnected and interdependent our planet’s ecosystems are. Studies have revealed similar processes at the poles and in European glaciers. Although this is the first study to document this effect in the Himalayas and there are significant geographical differences, the process is essentially the same. This goes to show that the effects of climate change are far-reaching and often hard to predict.
As our planet struggles to cope with the man-driven climate crisis, we will undoubtedly find out even more ways in which this process is affecting the environment.
Journal Reference: Mengke Chen et al. Release of Perfluoroalkyl Substances From Melting Glacier of the Tibetan Plateau: Insights Into the Impact of Global Warming on the Cycling of Emerging Pollutants, Journal of Geophysical Research: Atmospheres (2019). DOI: 10.1029/2019JD030566
Iceland’s first glacier lost to climate change will be remembered with a monument and a plaque soon to be unveiled at the site of the former glacier. The plaque’s message is a stern reminder that we know what is happening.
How will future generations look upon this monument? Words by Andri Snaer Magnason. Photo credit: Rice University.
“Ok is the first Icelandic glacier to lose its status as a glacier. In the next 200 years all our glaciers are expected to follow the same path. This monument is to acknowledge that we know what is happening and what needs to be done. Only you know if we did it,” it reads.
The state of affairs is pretty clear: the Earth’s climate is heating up due to greenhouse gas emissions produced by human activity. Sure, there is plenty of debate among politicians, particularly in circles who have a lot to gain by not taking action against it, but climate change denial has no scientific credibility. Simply put, we know it’s happening, and we know it’s because of us.
This is why researchers from Rice University in Houston teamed up with author Andri Snær Magnason and geologist Oddur Sigurðsson and the Icelandic Hiking Society to install a monument recognizing the place of the former Okjökull glacier in Borgarfjörður, Iceland.
Ok, as the glacier is called (“jökull” being merely a suffix which means “glacier”) is officially the first iceberg we’ve lost due to anthropogenic climate change. Now, a plaque will be unveiled at the site of the former monument, along with a letter for the future. Engraved on the plaque is also “415 ppm” — the amount of carbon dioxide in the atmosphere reported in May.
“This will be the first monument to a glacier lost to climate change anywhere in the world,” Howe said. “By marking Ok’s passing, we hope to draw attention to what is being lost as Earth’s glaciers expire. These bodies of ice are the largest freshwater reserves on the planet and frozen within them are histories of the atmosphere. They are also often important cultural forms that are full of significance.”
Of course, melting glacier ice is but one of the major effects of climate change. Ok was the first, but it will certainly not be the last. As the climate warms, we will continue to lose more and more. Whether or not we take action to prevent catastrophic damage from being done remains to be seen.
Before the Industrial Revolution, carbon dioxide levels in the atmosphere were stable at 280 ppm. Today’s rate of increase is more than 100 times faster than the increase that occurred when the last ice age ended, growing steadily and showing no signs of stopping.
Burning fossil fuels such as coal, petroleum, and natural gas is the leading cause of increased anthropogenic CO2, with deforestation being the second biggest cause.
We’re seriously underestimating Antarctica’s ability to push global sea level rise, a new study reports.
Image credits Luis Valiente.
Ice masses in the southern continent are becoming extremely unstable due to climate change, the authors explain, but this isn’t readily apparent. The team behind the study, with members from the Georgia Institute of Technology, NASA Jet Propulsion Laboratory, and the University of Washington, says that this hidden instability will likely accelerate water flow into the ocean and raise sea levels much faster than previously estimated.
Thawing the Antarctic
Five Antarctic glaciers have doubled their rate of ice loss over the last six years, according to the study, with at least one (the Thwaites Glacier) being in danger of collapse. While we can’t accurately estimate exactly how glacier runoff will evolve over the coming 50 to 800 years yet (this is dependant bot on our choices and on unknown factors such as topography), the team have done their best to cover all possible outcomes. For this, they’ve run 500 ice flow simulations for Thwaites’ evolution. While there was a wide range of variation between the scenarios, they all ended in the eventual collapse of Thwaites.
Glacier collapse has a lot to do with the geometry of the bedrock underpinning the ice. Glaciers whose leading edge ‘hangs’ in the ocean instead of being supported by bedrock are called tidewater glaciers. The point at which they glaciers start to float is the grounding line. Glacier instability/collapse first starts here.
Image credits Ted Scambos, Michon Scott / National Snow and Ice Data Center.
Warmer temperatures also heat up the ocean water, which starts eating away at the bottom of the glacier (which raises sea levels). This process also accelerates the rate at which glaciers fragment and float out into the sea. This is perhaps the most worrying process from a sea-level perspective: these bits of ice eventually melt in the wider ocean, but the process also speeds up the rate at which glaciers slide into the waters (as they’re no longer buoyed up by the ocean), leading to more and more melting.
“Once ice is past the grounding line and just over water, it’s contributing to sea level because buoyancy is holding it up more than it was,” says Alex Robel, an assistant professor in Georgia Tech’s School of Earth and Atmospheric Sciences and the study’s lead author. “Ice flows out into the floating ice shelf and melts or breaks off as icebergs.”
The simulations show that even if we do stop climate warming in the future, instability in Thwaites will keep feeding water into the global ocean at extremely fast rates compared to the baseline value. These results are based on present-day ice melt rates, meaning that higher rates of global warming will lead to faster and stronger melt rates than identified in this paper.
Worst of all, if Thwaites does collapse, it will trigger a feedback loop leading to more and more melt as it slides into the ocean at faster rates.
“If you trigger this instability, you don’t need to continue to force the ice sheet by cranking up temperatures. It will keep going by itself, and that’s the worry,” said Robel. “Climate variations will still be important after that tipping point because they will determine how fast the ice will move.”
“After reaching the tipping point, Thwaites Glacier could lose all of its ice in a period of 150 years. That would make for a sea level rise of about half a meter (1.64 feet),” adds NASA JPL scientist Helene Seroussi, a co-author of the paper. “The process becomes self-perpetuating”.
Currently, sea levels are 20 cm (almost 8 inches) above pre-industrial levels. Sea ice doesn’t raise sea levels as it melts — all that ice is already in the water so it already contributes a volume to the global ocean — but land-borne glaciers do. Antarctica holds the most land-supported ice, so it can have a very sizeable contribution to sea levels.
“There’s almost eight times as much ice in the Antarctic ice sheet as there is in the Greenland ice sheet and 50 times as much as in all the mountain glaciers in the world,” Robel explains.
It’s not yet clear whether Thwaites has reached the tipping point or not, but its outer edge is sinking into the ocean faster than previously recorded. The findings are particularly worrying as the success of current efforts to proof cities and installations against sea level rise are wholly dependent on having accurate predictions. However, the current study shows that our current forecasts aren’t very reliable.
“You want to engineer critical infrastructure to be resistant against the upper bound of potential sea level scenarios a hundred years from now,” Robel said. “It can mean building your water treatment plants and nuclear reactors for the absolute worst-case scenario, which could be two or three feet of sea level rise from Thwaites Glacier alone, so it’s a huge difference.”
Another surprising finding made by the team is that when climate conditions fluctuate strongly, Antarctic ice evens out the effects. Ice flow in such conditions will increase gradually, not wildly, but the instability produced the opposite effect in the simulations.
“The system didn’t damp out the fluctuations, it actually amplified them. It increased the chances of rapid ice loss,” Robel said.
“[Almost total ice loss in Thwaites] could happen in the next 200 to 600 years. It depends on the bedrock topography under the ice, and we don’t know it in great detail yet,” Seroussi said.
The paper “Marine ice sheet instability amplifies and skews uncertainty in projections of future sea-level rise” has been published in the journal Proceedings of the National Academy of Sciences.
Over the last 25 years, Antarctica’s ice sheet has thinned by up to 122 meters in certain areas. The most heavily-hit area is West Antarctica, where ocean melting is speeding up the process. However, affected glaciers are becoming unstable throughout the frozen continent, a new paper reports, meaning they lose more ice through melting and calving than they gain from snowfall.
Image via Pixabay.
The authors of the study, a team from the UK Centre for Polar Observation and Modelling (CPOM) led by Professor Andy Shepherd from the University of Leeds, used 25 years’ worth of altimetry data recorded by European Space Agency satellites and a regional climate model to determine the state of Antarctic ice.
Antarctic, shaken, no ice, please
“In parts of Antarctica the ice sheet has thinned by extraordinary amounts, and so we set out to show how much was due to changes in climate and how much was due to weather,” Professor Shepherd explains.
“While the majority of the ice sheet has remained stable, 24% of West Antarctica is now in a state of dynamical imbalance,” the paper reads.
The patterns of glacier thinning have not been static, the team reports. Since 1992, glaciers across more than 24% of West Antarctica has begun to thin, as did those associated with the continent’s largest ice streams — the Pine Island and Thwaites Glaciers. These two glaciers are now melting a full five times faster than they were at the beginning of the survey, the team notes. All in all, fluctuations in snowfall do cause small changes in glacier volume for a few years at a time, but the significant changes observed by the team have persisted for decades and are indicative of the effects of climate-change-induced glacier instability, the team explains.
The data used in the study included over 800 million measurements of the Antarctic ice sheet height recorded by the ERS-1, ERS-2, Envisat, and CryoSat-2 satellite altimeter missions between 1992 and 2017 and simulations of snowfall over the same period produced by the RACMO regional climate model. This wealth of data allowed the team to tease apart changes in ice sheet height caused by weather — such as variations in snowfall — from longer-term changes caused by climate — such as warmer ocean water that melts ice away. To separate the two effects, the researchers compared the surface height readings obtained in the field to changes in snowfall they simulated using the RACMO model. In effect, any discrepancies between the two datasets are the product of glacier imbalance (i.e. of climate change).
“Knowing how much snow has fallen has really helped us to detect the underlying change in glacier ice within the satellite record,” says Professor Shepherd. “We can see clearly now that a wave of thinning has spread rapidly across some of Antarctica’s most vulnerable glaciers, and their losses are driving up sea levels around the planet.”
“Altogether, ice losses from East and West Antarctica have contributed 4.6 mm to global sea level rise since 1992.”
The study is a good example of how satellite data can be used to study large climate trends ongoing on our planet. This is especially true in hostile environments such as the arctic and antarctic, where ground-level missions are not only difficult but potentially deadly, as well.
The paper “Trends in Antarctic Ice Sheet Elevation and Mass” has been published in the journal Geophysical Research Letters.
After finding microplastics in the deep oceans, tap water, and even inside humans, researchers have now discovered another ‘pristine’ area polluted by plastic: remote mountain glaciers.
Microplastics have been found in areas once thought pristine such as glaciers. Image credits: NASA / James Yungel.
It’s not the first time plastic pollution has been found in ice. Previously, researchers have found plastic in remote regions such as the Arctic — now, the same researchers have now discovered microplastics in the Forni Glaciers in the Swiss Alps.
Roberto Sergio Azzoni at the University of Milan and colleagues analyzed sediment samples from the glaciers, finding around 75 particles of microplastic per kilogram of sediment. If this is a representative sample, that would add up to 162 million plastic particles across the entire Forni glacier.
Microplastics are essentially any plastic piece under the size of 5 millimeters (0.2 inches) — whether they were produced this or degraded into smaller pieces. They generally enter natural ecosystems from a variety of sources such as cosmetics, clothing, and industrial processes. In this case, the plastic parts have a “local” origin: they most likely come from hi-tech hiking gear.
It’s a stern reminder that anywhere humans go, plastic pollution follows close by.
A 2014 study estimated that there are between 15 and 51 trillion individual pieces of microplastic in the world’s oceans. A more recent study from 2017 found that most of the world’s tap water is also contaminated with microplastics, as water filtration systems are unable to remove these small specs. Creatures of all shapes and sizes from marine ecosystems have also been found with substantial quantities of ingested plastic; often times, this turns out to be fatal. It’s estimated that it takes in excess of 1,000 years for microplastics to fully degrade in the environment.
Policy attempts at reducing microplastics have been shy. In 2018, the Japanese government unanimously voted a law to reduce microplastic pollution, but the law doesn’t specify any penalties for companies that don’t comply. In the US, states like Illinois have banned cosmetics containing microplastics, and at the national level, a 2015 law signed by President Barack Obama banned “rinse-off” cosmetic products that contain microplastics, but the law does not apply to other products such as household cleaners. The European Chemical Agency has also recommended measures to reduce microplastic pollution, but no concrete measures have been taken yet.
The latest findings have been presented at the European Geosciences Union conference in Vienna.
Glacier ice is warmer than you’d expect — and that raises concerns regarding their ability to withstand future climate change.
Image via Pexels.
Temperature measurements performed inside the world’s highest glacier — on the slopes of Mount Everest — reveals that these chunks of ice are more vulnerable to climate change than we believed. Not only is the ice warmer than expected, it’ actually warmer than the mean annual temperature at the site.
“The temperature range we measured from drill sites across the Khumbu Glacier was warmer than we expected — and hoped — to find,” says Dr. Duncan Quincey, paper co-author.
“Internal temperature has a significant impact on the complex dynamics of a glacier, including how it flows, how water drains through it and the volume of meltwater runoff – which makes up a crucial part of the water supply for millions of people in the Hindu Kush-Himalaya region.”
So what’s the big deal? Well, in short, warm ice is more vulnerable to climate change because it takes less of a nudge (in temperature) to send it melting. The study reports that minimum temperatures inside the Khumbu Glacier (Nepal) are only -3.3°C (26.6°F); even this minimum temperature is a full 2°C warmer than the mean annual temperature at the site.
The ice in the glacier is, quite literally, warmer than the air around it.
Data for the project was obtained during the 2017 EverDrill project, let by Dr. Qunincey. It was the first successful effort to drill into the Khumbu Glacier and record temperatures deep below the surface layer. Working at altitudes of up to 5 meters, the research team used a specially adapted car wash unit to produce a pressurised jet of hot water to drill boreholes up to 190 metres into the glacial ice.
The results suggest that even minor changes in atmospheric temperatures can have a significant effect on the integrity of high-elevation Himalayan glaciers — if not all glaciers. It raises concerns that high-elevation Himalayan glaciers are vulnerable to even minor atmospheric warming and will be especially sensitive to future climate warming. Study lead author Katie Miles from Aberystwyth University explained that the Khumbu Glacier’s vulnerability may have serious consequences for the quantity (and reliability) of meltwater runoff in the coming decades and it will be important to determine if other glaciers in the region have similar internal characteristics to Khumbu.
“Until now, the limited amount of data collected from glaciers in this region has made it difficult to predict how environmental change could affect the glaciers’ internal dynamics,” says Dr. Quincey.
“Insights from the EverDrill project can aid scientists in forecasting the impact of global warming and how long the region can rely on meltwater to feed downstream water supply.”
The paper “Direct isotopic evidence of biogenic methane production and efflux from beneath a temperate glacier” has been published in the journal Scientific Reports.