Tag Archives: glaciers

World’s glaciers hold less ice than previously thought

Scientists have measured the thickness and movement of over 250,000 mountain glaciers using a set of new techniques. The study revised previous estimates of glacial ice volume, finding that there’s 20% less ice available in the world’s glaciers.

Darker colors overlayed on Peru’s Cordillera Blanca range, signify faster glacial speed. Image credit: The researchers.

Almost two billion people rely on glaciers and snowpack as their main source of drinking water, according to previous estimates. But as temperatures rise and rainfall patterns shift because of climate change, these glaciers are thinning and retreating. When snowpacks shrink, so does the amount of water stored in these water towers.

This raises concerns for communities that rely on seasonal melt from glaciers to feed local rivers, from which they obtain water for drinking, power generation, and agriculture. If glaciers have less ice, as the study showed, water will run out in many parts of the world sooner than expected, bringing a set of problems for communities.

“These communities need to know how long their glaciers will continue to provide water and what to expect as the glaciers disappear so they can prepare.” Mathieu Morlighem, one of the authors of the study, wrote in a blog post. “In most places, we found significantly lower total ice volumes than previous estimates indicated.”

Researching glaciers

Using satellite imagery, the researchers created the world’s first atlas to measure the thickness and movement of glaciers. Glacier ice acts like thick syrup when it’s thick enough, Morlighem explained. This allows to measure how to face the ice is moving using satellite images and map its speed, ranging from a few feet to about one mile per year.

The researchers used over one million hours of computing time to analyze almost 812,000 pairs of high-resolution satellite photos. They covered 98% of the areas of the planet that were covered in glaciers from 2017 and 2018. That includes glaciers that haven’t been mapped before in areas of South America, Europe, and New Zealand. 

The study found more ice in some regions and less in others, with the overall result being that there’s less ice worldwide than previously thought. In the tropical Andes mountains of South America, ranging from Venezuela to Chile, there’s 23% less ice than previously estimated, which means those living downstream will have less time to adjust to climate change.

On the contrary, the Himalayan mountains in Asia were found to have one-third more ice than previous estimates. This gives communities that rely on those glaciers more time to cope with climate change but doesn’t change the fact that glaciers are melting because of temperature rise. Almost everywhere else the ice is thinner, the study showed.

“Policymakers should look at these new estimates to revise their plans. We do not provide new predictions of the future in this study, but we do provide a better description of what the glaciers and their water supplies look like today,” Morlihem wrote. “We have made a lot of progress in reducing the overall uncertainty.

The study was published in the journal Nature. 

Global ice loss rate increased by over 65% in the last two decades

New research reports that the planet is losing ice at an ever-faster rate. This is the first time satellite data has been used to survey global ice loss rates, according to the authors, finding that it has increased by over 50% in the last three decades, and 65% over the last two decades.

Furthermore, the authors explain that our planet has lost around 28 trillion tons of ice between 1994 and 2017, which they say is roughly the same quantity in an ice sheet the size of the UK and 100 meters thick — and the rate of melt is increasing. If left unchecked, this will lead to massive damage as communities and natural habitats on today’s coasts will flood.

No-more-ice Age

“Although every region we studied lost ice, losses from the Antarctic and Greenland ice sheets have accelerated the most. The ice sheets are now following the worst-case climate warming scenarios set out by the Intergovernmental Panel on Climate Change,” says lead author Dr. Thomas Slater, a Research Fellow at Leeds’ Centre for Polar Observation and Modelling.

“Sea-level rise on this scale will have very serious impacts on coastal communities this century.”

Led by members from the University of Leeds, the team reports that there has been a 65 % increase in the rate of melt over the 23 years it investigated, driven mainly by losses in Antarctica and Greenland. In raw numbers, we went from 0.8 trillion tons of ice melting per year in the 1990s to 1.3 trillion tons per year by 2017.

Although we had a better idea than ever before about how individual elements in the Earth’s ice system fared, we were still lacking data on how the planet as a whole was evolving. This study, says Dr. Slater, is the first to examine all of the ice at the same time, using satellite data. It includes 215,000 mountain glaciers, the ice sheets of Greenland and Antarctica, ice shelves around Antarctica, as well as sea ice bobbing along the Arctic and Southern Oceans.

The faster rates of melt are being caused by warmer waters and bodies of air — the atmosphere and oceans have warmed by 0.26°C and 0.12°C per decade since the 1980, respectively. Atmospheric melting was the prime offender (responsible for around 68% of the extra melting), with the remainder (32%) coming down to oceanic melting. The geographic distribution of ice on the planet explains the higher rates of atmospheric melting (not all ice comes in contact with the ocean).

All the elements investigated in the study lost ice, but the largest losses were in Arctic Sea ice (7.6 trillion tons) and Antarctic ice shelves (6.5 trillion tons). Mountain glaciers lost a total of 6.1 trillion tons of ice, the Greenland ice sheet lost 3.8 trillion tons, while the Antarctic ice sheet lost some 2.5 trillion tons of ice.

This contributed around 35 millimeters of global sea level rise. The team explains that every centimeter of sea level rise puts an estimated one million people at risk of being displaced by water.

“Sea ice loss doesn’t contribute directly to sea level rise but it does have an indirect influence. One of the key roles of Arctic sea ice is to reflect solar radiation back into space which helps keep the Arctic cool,” says Dr. Isobel Lawrence, a Research Fellow at Leeds’ Centre for Polar Observation and Modelling.

“As the sea ice shrinks, more solar energy is being absorbed by the oceans and atmosphere, causing the Arctic to warm faster than anywhere else on the planet. Not only is this speeding up sea ice melt, it’s also exacerbating the melting of glaciers and ice sheets which causes sea levels to rise.”

Mountain glaciers contributed around 25% of the sea level rise seen over this period, despite storing only 1% of the world’s ice. Their melting is especially worrying, as mountain glaciers are essential sources of fresh water for communities around the world.

It is estimated that for every centimetre of sea level rise, approximately a million people are in danger of being displaced from low-lying homelands.

The paper “Review article: Earth’s ice imbalance” has been published in the journal The Cryosphere.

As glaciers melt, new islands are discovered in the Arctic

The effects of climate change are becoming every day more visible in the Arctic. The Russian navy said it has discovered five new islands revealed by melting glaciers when carrying out an expedition in August and September in the area.

Credit Wikipedia Commons

The head of the northern fleet, Vice-Admiral Alexander Moiseyev, said this was mainly due to the “changes to the ice situation,” speaking at a press conference. “Before these were glaciers; we thought they were (part of) the main glacier. Melting, collapse, and temperature changes led to these islands being uncovered.”

According to a recent report by the United Nations, glacier loss in the Arctic in the period from 2015 to 2019 was more than in any other five-year period on record. This agrees with other changes seen in the Arctic due to global warming such as ecosystems under threat.

Russia has opened a string of military and scientific bases in the Arctic in recent years, with interest in the region growing as rising temperatures open up shipping routes and make hitherto inaccessible mineral resources easier to exploit.

The summer expedition to two archipelagoes – Franz Josef Land and Novaya Zemlya – involved a team of 60 people, including civilians from the Russian Geographic Society, and was the first onboard a rescue towboat instead of an icebreaker.

“The two months this year when we held our expedition to Franz Josef Land can be described as warm,” said Denis Krets, commander of the northern fleet’s expedition force. “We were very lucky because we could land on islands where not every year the shore and the inshore water is free of ice.”

The islands, which will be named soon, were found in Vize Bay off Novaya Zemlya, a vast mountainous archipelago with two main islands. They had previously been seen on satellite images, but the expedition was the first to confirm them.

Russia’s Defense Ministry also said it had confirmed the existence of an island that had been previously mapped as a peninsula of Hall Island, part of the Franz Josef Land archipelago, west of Novaya Zemlya.

If global warming is stabilized at 1.5°C above pre-industrial levels, the Arctic ocean would only be ice-free in September – the month with the least ice – once in every hundred years. For global warming of 2°C, this would occur up to one year in three.

Permafrost ground that has been frozen for many years is warming and thawing and widespread permafrost thaw is projected to occur in the 21st century. Even if global warming is limited to well below 2°C, around 25% of the near-surface (3-4-meter depth) permafrost will thaw by 2100.

Matterhorn.

The Alps will lose all their glaciers by 2100 if we don’t do something about it

We could be looking at ice-free Alps by 2100. And yes, it’s because of climate change.

Matterhorn.

Matterhorn, the ‘Peak of the Meadows’, a mountain in the Alpine range straddling the border between Switzerland and Italy.
Image via Pixabay.

New research found that the European Alps could lose all their glacier ice by the end of the century. Under a limited warming scenario, the mountain range would lose about two-thirds of their current ice volume. However, under a strong, unmitigated warming scenario, virtually all Alpine glaciers will be gone by 2100.

Alps, stirred, no ice

“Glaciers in the European Alps and their recent evolution are some of the clearest indicators of the ongoing changes in climate,” says senior co-author Daniel Farinotti from ETH Zurich.

“The future of these glaciers in indeed at risk, but there is still a possibility to limit their future losses.”

The study provides the most up-to-date estimates of how Alpine glaciers (of which there are around 4000) will evolve in the coming decades, the team writes. According to the results, large changes in glacier ice volume in this area will occur in the next few decades. From 2017 to 2050, for example, the team expects roughly 50% of their volume to melt away — regardless of any slashing of emissions on our part (due to climate inertia). After 2050, however, “the future evolution of glaciers will strongly depend on how the climate will evolve,” says study-leader Harry Zekollari.

“In case of a more limited warming, a far more substantial part of the glaciers could be saved,” Zekollari, a researcher at ETH Zurich and the Swiss Federal Institute for Forest, Snow and Landscape Research, now at Delft University of Technology in the Netherlands, adds.

This melting will have a pronounced impact on local alpine ecosystems, of which the glaciers play an important part. Local landscape and economy are also likely to see perturbations, the team adds. The glaciers supply local ecosystems with fresh water, and keep local agriculture and hydroelectricity production going in warm or dry periods. They also attract a lot of tourists.

Zekollari and his team used computer models that combined ice-flow and ice-melt processes with observational data to see how Alpine glaciers will fare in the future. They used 2017, when Alpine glaciers had a total volume of about 100 cubic kilometers, as the ‘present day’ reference.

Under a limited warming scenario (RCP2.6), where greenhouse gas emissions would peak in the next few years and then decline sharply — leading to warming below 2°C compared to pre-industrial levels by 2100 — Alpine glaciers would lose around 37 cubic kilometers of ice by the end of the century.

Under a high-emissions scenario (RCP8.5), where emissions would continue to rise rapidly over the next few decades, the glaciers would be virtually gone by 2100.

“In this pessimistic case, the Alps will be mostly ice free by 2100, with only isolated ice patches remaining at high elevation, representing 5% or less of the present-day ice volume,” says Matthias Huss, a researcher at ETH Zurich and co-author of the study.

It pays to keep in mind that our current emissions are just above the quantities considered for this scenario.

All in all, no matter what we do, the Alps would lose around 50% of their glacier volume by 2050. This happens because all the greenhouse gases we’ve already emitted will linger in the atmosphere for a while — until they break down, mean temperature increase is largely independent of new emissions. However, what happens after 2050 is very much in our hands. Another reason for this decline in glacier volume by 2050, the team adds, is that the Alpine glaciers currently have ‘too much’ ice. Their volume, especially at lower elevations, still reflects the colder climate of the past, as glaciers are slow to respond to changing climate conditions.

Even if we manage to stop the climate from warming any further, keeping it at the level of the past 10 years, glaciers would still lose about 40% of their present-day volume by 2050 because of this “glacier response time,” says Zekollari.

The paper ” Modelling the future evolution of glaciers in the European Alps under the EURO-CORDEX RCM ensemble” has been published in the journal The Cryosphere.

Water.

Sea level change isn’t constant across the East Coast — because of long-past glaciers

A new study explains why different areas along the U.S. East Coast see significantly more sea level change than others.

Water.

Image credits Dimitris Vetsikas.

Seas and oceans across the globe are creeping ever so slowly upwards as climate change warms them up and melts glaciers big and small. However, local sea levels aren’t (surprisingly) the same everywhere — and this holds true for the U.S. East Coast as well. A new study published by researchers from the Woods Hole Oceanographic Institution (WHOI) comes to explain why.

Been under a lot of pressure lately

Over the last century, coastal communities near Cape Hatteras (North Carolina) and the Chesapeake Bay (Virginia) have seen about a foot and a half of sea level rise.  New York City and Miami, in contrast, have only seen roughly two-thirds of that rise (i.e. one foot) over the same period. Farther north in Portland, Maine, for example, sea levels only rose only about half a foot.

Which is weird, right? I mean, all the Earth’s oceans are linked together so, their water should be level, right? Not if you’re on a period of post-glacial rebound, says lead author Chris Piecuch.

Vast areas of land in the Northern Hemisphere, including Canada and parts of the Northeast U.S, were covered in massive glaciers during the last Ice Age, he explains. This effectively squashed the lands, pushing them down into the mantle (the crust is essentially a jigsaw puzzle of solid pieces floating on molten rock — see here). These ice sheets peaked in size and mass during the Last Glacial Maximum some 26,500 years ago, and then started melting to the state we see today. As they did so, the pressure they exerted on the ground also disappeared — and these areas started to rebound. Neighboring lands, meanwhile, started sinking, creating sort of a seesaw effect.

That effect continues to this day, Piecuch explains.

For the study, Piecuch and his team gathered tidal gauge measurements of sea levels in areas such as Norfolk Naval Station in Virginia and the Outer Banks in North Carolina. They also drew on GPS satellite data to see how much local landmasses had moved up and down over time, and looked to fossils recovered from salt marshes (which are a good indicator of past coastal sea levels). They combined all of this observational data with complex geophysical models to produce a more complete view of sea level changes since 1900 than ever before.

Post-glacial rebound, they found, accounted for most of the variation in sea level rise along the East Coast. Interestingly, however, when that factor was removed from the dataset, the team found that “sea level trends increased steadily from Maine all the way down to Florida.”

“The cause for that could involve more recent melting of glaciers and ice sheets, groundwater extraction and damming over the last century,” Piecuch says. “Those effects move ice and water mass around at Earth’s surface, and can impact the planet’s crust, gravity field and sea level.”

“Post-glacial rebound is definitely the most important process causing spatial differences in sea level rise on the U.S. East Coast over the last century. And since that process plays out over millennia, we’re confident projecting its influence centuries into the future. But regarding the mass redistribution piece of the puzzle, we’re less certain how that’s going to evolve into the future, which makes it much more difficult to predict sea level rise and its impact on coastal communities.”

The paper “Origin of spatial variation in US East Coast sea-level trends during 1900–2017” has been published in the journal Nature.

Ice cliffs on Mars.

Cliffs of pure, blue water-ice spotted just below Mars’ surface

Mars seems to be hiding a hoard of pristine frozen water just below the surface, a new paper reports.

Ice cliffs on Mars.

Thick bands of ice (blue) spotted in Martian cliff faces.
Image credits NASA / JPL / USG / University of Arizona.

The Mars Reconnaissance Orbiter (MRO) has been beaming back high-resolution images of the planet for over a decade now, and for most of the time, nothing too special pops up. However, a few years ago Colin Dundas, a geologist at the U.S. Geological Survey in Flagstaff, Arizona, spotted something hidden below Mars’ rusty, dusty exterior — a pale line of blue.

Dundas subsequently found the same structures at seven other sites on Mars. These formations, wedged in the flanks of tall, steep cliffs, appear to be nearly pure ice — water-ice, that is.

In a new paper, researchers argue these findings suggest there are vast stores of underground ice tantalizingly close to the surface, even at low martial latitudes (i.e. closer to the equator). Such reserves could help researchers tease out the planet’s history, and dramatically improve the feasibility of any potential colonies on Mars.

Rust and ice

“This kind of ice is more widespread than previously thought,” says Dundas, paper co-author.

We’ve found ice on Mars before. There’s a thick cover of it on the planet’s poles (which Elon Musk thinks we should nuke) and MRO’s radar suite has picked up signatures of buried ice across Mars. Some have argued that those deposits are the remains of ancient glaciers, a by-gone of an age when the planet had a very different climate. However, based on MRO’s radar data, we can’t tell how deep these icy formations are, and whether they’re made up of solid chunks or tiny drops frozen in the soil’s pores.

MRO brought us even more evidence of ice on Mars in the past: pools of (what appears to be) pure ice, puddled on the floors of fresh meteorite craters. Still, there was no way of ascertaining if such pools were connected to underground glaciers or isolated patches of fluid.

Mars.

Mars, with some of its polar ice visible.
Image credits NASA / JPL.

The structures described in this new paper could plug those holes in our understanding. Each of the cliff-faces identified in the study, standing at roughly 100 meters (32.8 feet) tall, seem to the naked face of a glacier, the team reports. MRO could thus observe the glaciers in cross-section (like seeing the layers in a slice of cake), and the team revisited all the sites to see how they changed over time.

The most significant find is that the ice persists through the Martian summer. This is significant because it points to solid, massive structures — a light frosting would have simply vaporized. Further evidence in support of this is that last year the orbiter caught several boulders tumbling out of the cliff faces, suggesting they were being slowly eroded from a large deposit at surface level.

All of this strongly suggests that the surface-level ice and the large subsurface deposits are connected, the authors say.

Layer cake

“This deep, thick, pure ice extends almost all the way up to the surface” says co-author Ali Bramson.

Such structures promise to yield a layered record of past martian climates, similarly to how polar ice caps do on Earth. Alternatively, they would be a prime resource for colonists.

Banding in the glaciers suggests that the slabs are stacked — meaning they formed over many seasons as layers of snow got compressed into ice in different climate cycles. Winds then carried grit over each layer, sealing them apart, and creating the banding. It’s a similar process to how ice caps and glaciers form on Earth, and so the team believes that drilling a core into one of these deposits and bringing it back for analysis would offer geologists a treasure trove of information about the Martian climate.

The glaciers are also a boon for colonists. Water is crucial for astronauts because it can be mixed with CO2 (the most common gas in Mars’ atmosphere) to create breathable oxygen and methane to be used in rockets. But any deposits would only really be any good if they’re no more than a few meters below the surface — that’s why the ice-cliffs are so exciting.

The cliffs are found at about 55° north or south, however, which grow frigid and dark in the Martian winter. These aren’t very good areas for a solar-powered human base, so NASA study was limited to sites to within 50° of the equator. Following these new findings, however, NASA wants to extend its exploration program closer to the Martian tropics.

The paper “Exposed subsurface ice sheets in the Martian mid-latitudes” has been published in the journal Science.

Taking a look at the ‘little ice age’ of 1810

ice-ageGlobal warming is one of the main concerns on everybody’s lips, causing more and more damage to the environment every year, sometimes in ways that seem hard to believe; everyday there seems to be a new report about something that went, is going, or will be going terribly wrong. However, in the early 1800s, the situation was in diametric contradiction with everybody being worried about a global cooling that seemed to come out of nowhere.

It all peaked in 1816, when in most places of the world there was actually no summer at all ! That year’s chill was blamed by climatologists on the eruption of the Indonesian volcano called Tambora, but why the few years before 1816 were also way colder than usually remained a mystery. However, newly uncovered evidence from the ice of Antarctica and Greenland suggests that another volcanic eruption was probably responsible for it.

Jihong Cole-Dai, a chemistry professor at South Dakota State University led the expeditions that cleared this intriguing question that seemed to be without an answer. He found evidence of another eruption some 6 years before the 1815 one (which was responsible for the 1816 cooling). Here’s why major volcano eruptions have such a big influence:  they practically dump immense quantities of sulfur dioxide and ash that act pretty much like an umbrella, shading the Earth and reflecting sunlight for several years.

However, it’s obvious that a single volcanic eruption couldn’t be responsible for ‘freezing’ a whole decade. Cole-Dai and his team found evidence of one more eruption that helped trigger the mini ice age. However, they weren’t able to pinpoint the volcano, saying that they only know it has to be somewhere close to the equator and really big. I don’t know for sure but I’m guessing that a more detailed analysis will give some more clues regarding this volcano and researchers will be able to find it, despite the fact that it seems to be a ‘needle in the haystack’ kind of search.

Glaciers Are Melting Faster Than Expected, UN Reports

glacier melt

Recently, more and more people are beginning to claim that the melting of glaciers caused by global warming is all fuss for nothing. Well, that couldn’t be further from the truth! According to the official figures published by the UN Environment Programme (UNEP) the world’s glaciers are continuing to melt, at a higher rate than expected.Data from close to 30 reference glaciers in nine mountain ranges indicate that between the years 2004-2005 and 2005-2006 the average rate of melting and thinning more than doubled. That’s some really tough news, that surpass even the most pesimistic predictions.

The Service calculates how much glaciers thicken or thinnen in terms of ‘water equivalent’. A two C degree warming in 30 years from now will probably lead to drastic and very unpleasant results. Here’s what Achim Steiner, UN Under-Secretary General and UNEP Executive Director, said:

“Millions if not billions of people depend directly or indirectly on these natural water storage facilities for drinking water, agriculture, industry and power generation during key parts of the year,” said Mr Steiner. “There are many canaries emerging in the climate change coal mine. The glaciers are perhaps among those making the most noise and it is absolutely essential that everyone sits up and takes notice,” he said.
“The litmus test will come in late 2009 at the climate convention meeting in Copenhagen. Here governments must agree on a decisive new emissions reduction and adaptation-focused regime. Otherwise, and like the glaciers, our room for man oeuvre and the opportunity to act may simply melt away,” he added.