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Sebastian Jones

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Re: Glaciers worldwide decline faster than ever
« Reply #50 on: March 25, 2019, 02:45:14 PM »
A multi- year glacier monitoring program conducted by an environmental studies class in Iceland provides a record of glacier retreat.
https://www.hakaimagazine.com/news/glacier-lessons-as-a-glacier-lessens/

kassy

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Re: Glaciers worldwide decline faster than ever
« Reply #51 on: June 05, 2019, 01:26:39 PM »
Melting small glaciers could add 10 inches to sea level by 2100

According to a new analysis, glaciers worldwide are projected to lose anywhere from 18 to 36 percent of their mass by 2100, resulting in almost 10 inches (25 cm) of sea level rise. That’s without any contribution from melting of the vast Greenland and Antarctic ice sheets, which were not included in the study. According the researchers, the behavior of smaller glaciers requires modeling methods unlike those for the major ice sheets.

https://earthsky.org/earth/melting-small-glaciers-sea-level-rise
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ArcticMelt2

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Re: Glaciers worldwide decline faster than ever
« Reply #52 on: June 09, 2019, 04:13:18 PM »
The general picture of the melting glaciers in the world (for some reason it is believed that the glaciers on Kerguelen Islands in the Southern Ocean will be good).

https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2018EF001139




ArcticMelt2

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Re: Glaciers worldwide decline faster than ever
« Reply #53 on: June 09, 2019, 04:34:41 PM »
Melting small glaciers could add 10 inches to sea level by 2100

According to a new analysis, glaciers worldwide are projected to lose anywhere from 18 to 36 percent of their mass by 2100, resulting in almost 10 inches (25 cm) of sea level rise.
https://earthsky.org/earth/melting-small-glaciers-sea-level-rise

In this work, the total volume of remaining mountain glaciers is estimated much less (only 40 cm of sea level rise).

https://www.nature.com/articles/s41586-019-1071-0

Quote
Glaciers distinct from the Greenland and Antarctic ice sheets cover an area of approximately 706,000 square kilometres globally1, with an estimated total volume of 170,000 cubic kilometres, or 0.4 metres of potential sea-level-rise equivalent2

Quote
Here we use an extrapolation of glaciological and geodetic observations to show that glaciers contributed 27 ± 22 millimetres to global mean sea-level rise from 1961 to 2016.

The greatest losses are due to Alaska:


ArcticMelt2

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Re: Glaciers worldwide decline faster than ever
« Reply #54 on: June 09, 2019, 04:40:35 PM »
https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2018EF001139

Interestingly, it turns out that 80% total mass of the remaining mountain glaciers are located on the mountains of southern Alaska.

This is strange, considering that the oldest mountain ice is found in Tibet.

mitch

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Re: Glaciers worldwide decline faster than ever
« Reply #55 on: June 09, 2019, 06:14:08 PM »
That most of the alpine glacier mass is in Alaska makes sense, since it sets next to a relatively warm water mass (the North Pacific), so has a major water source.  However, significant parts of the new deposition melt out every summer. Now that the temperatures have warmed, there is net loss along the glaciers.

ArcticMelt2

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Re: Glaciers worldwide decline faster than ever
« Reply #56 on: June 09, 2019, 06:24:20 PM »
That most of the alpine glacier mass is in Alaska makes sense, since it sets next to a relatively warm water mass (the North Pacific), so has a major water source.  However, significant parts of the new deposition melt out every summer. Now that the temperatures have warmed, there is net loss along the glaciers.

I agree, apparently there is very high ice mobility. Ice in the cores of Alaska has an age at best of several hundred years. For comparison, some Alpine glaciers are supposed to be 10 thousand years old or more.

https://www.the-cryosphere.net/10/2779/2016/tc-10-2779-2016.pdf

Quote
In the western Alps, an ice core extracted from Colle Gnifetti (4450 m, Monte Rosa, Italian–Swiss border) provided evidence for more than ∼ 10 kyr-old ice in its lower section (Jenk et al., 2009), suggesting a continuous glaciation of at least the highest locations of the western Alps throughout the Holocene.

Or maybe Alaska has been studied much worse than the Alps, and it is also possible to find the oldest ice there.

P.S. Managed to find evidence of millennial ice in Alaska.

https://www.alaskapublic.org/2019/02/25/climate-warming-demonstrated-in-ice-core-samples-of-the-alaska-range/

Quote
The bottom 8 inches of the first 682-foot ice core (of two) collected from Mt. Hunter. Imbedded pebbles and discolored ice indicate that this represents the bottom of the glacier in contact with underlying rock. This ice is at least 5,000 years old, and most likely 20,000 years old. Analyses of this deepest portion of the ice core, representing thousands of years or time, are ongoing. (Photo courtesy of Mike Waszkiewicz)

Osterberg, an Associate Professor of Earth Sciences at Dartmouth College, and his colleagues have been conducting field research on Mt. Hunter since 2008 to capture climate history preserved in ice core samples. In 2013, two separate 700-foot-long ice cores were collected at an ideal location on Mt. Hunter’s summit plateau.
« Last Edit: June 09, 2019, 06:37:11 PM by ArcticMelt2 »

Klondike Kat

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Re: Glaciers worldwide decline faster than ever
« Reply #57 on: June 09, 2019, 08:11:14 PM »
https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2018EF001139

Interestingly, it turns out that 80% total mass of the remaining mountain glaciers are located on the mountains of southern Alaska.

This is strange, considering that the oldest mountain ice is found in Tibet.

I haven’t had the chance to read this yet, but I suspect that they are not including the glaciers ofTibet

ArcticMelt2

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Re: Glaciers worldwide decline faster than ever
« Reply #58 on: June 09, 2019, 08:25:28 PM »
https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2018EF001139

Interestingly, it turns out that 80% total mass of the remaining mountain glaciers are located on the mountains of southern Alaska.

This is strange, considering that the oldest mountain ice is found in Tibet.

I haven’t had the chance to read this yet, but I suspect that they are not including the glaciers ofTibet

They write that the amount of ice in Alaska is 10 times greater than in Tibet.

For example, Alaska has the thickest mountain glacier in the world.

https://en.wikipedia.org/wiki/Taku_Glacier

Quote
Using radio-echo soundings and seismic reflections, we measured cross-sections of Taku Glacier, near Juneau, Alaska, to resolve inconsistencies in previous measurements and to understand better the glacier’s dynamics. The maximum thickness is about 1477 m and the minimum bed elevation is about 600 m below sea level, which establishes Taku Glacier as the thickest and deepest temperate glacier yet measured.

ArcticMelt2

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Re: Glaciers worldwide decline faster than ever
« Reply #59 on: June 09, 2019, 08:40:32 PM »
In general, the discovery of the most ancient ice in Tibet in 1987 year was later questioned.

https://www.researchgate.net/publication/324453299_Age_of_the_Tibetan_ice_cores

Shallower wells (100–200 meters versus 300 meters) on neighboring glaciers gave an age of less than 100 thousand years.

In this connection, a new well was drilled at Guliya Ice Cap in 2015. And she fully confirmed that this Tibetan ice is the oldest of those found outside of Antarctica.

https://news.osu.edu/researchers-capture-oldest-ice-core-ever-drilled-outside-the-polar-regions/

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December 04,2017

Researchers capture oldest ice core ever drilled outside the polar regions

New Orleans—The oldest ice core ever drilled outside the polar regions may contain ice that formed during the Stone Age—more than 600,000 years ago, long before modern humans appeared.

Researchers from the United States and China are now studying the core—nearly as long as the Empire State Building is tall—to assemble one of the longest-ever records of Earth’s climate history.

What they’ve found so far provides dramatic evidence of a recent and rapid temperature rise at some of the highest, coldest mountain peaks in the world.

At the American Geophysical Union meeting on Thursday, Dec. 14, they report that there has been a persistent increase in both temperature and precipitation in Tibet’s Kunlun Mountains over the last few centuries. The change is most noticeable on the Guliya Ice Cap, where they drilled the latest ice core. In this region, the average temperature has risen 1.5 degrees Celsius (2.7 degrees Fahrenheit) in the last 50 years and the average precipitation has risen by 2.1 inches per year over the past 25 years.

Lonnie Thompson, Distinguished University Professor in the School of Earth Sciences at The Ohio State University and co-leader of the international research team, said that the new data lend support to computer models of projected climate changes.

“The ice cores actually demonstrate that warming is happening, and is already having detrimental effects on Earth’s freshwater ice stores,” Thompson said.

“The water issues created by melting ice on the Third Pole, along with that from the Arctic and Antarctica, have been recognized as important contributors to the rise in global sea level. Continued warming in these regions will result in even more ice melt with the likelihood of catastrophic environmental consequences,” Yao noted.Earth’s largest supply of freshwater ice outside of the Arctic and Antarctica resides in Tibet—a place that was off limits to American glaciologists until 20 years ago, when Ohio State’s Byrd Polar and Climate Research Center (BPCRC) began a collaboration with China’s Institute of Tibetan Plateau Research. There, glaciologist Yao Tandong secured funding for a series of joint expeditions from the Chinese Academy of Sciences.

The name “Third Pole” refers to high mountain glaciers located on the Tibetan Plateau and in the Himalaya, in the Andes in South America, on Kilimanjaro in Africa, and in Papua, Indonesia—all of which have been studied by the Ohio State research team.

Of particular interest to the researchers is a projection from the Intergovernmental Panel on Climate Change that future temperatures on the planet will rise faster at high altitudes than they will at sea level. The warming at sea level is expected to reach 3 degrees Celsius by the year 2100, and possibly double that, or 6 degrees Celsius, at the highest mountain peaks in the low latitudes.

“The stable isotopic records that we’ve obtained from five ice cores drilled across the Third Pole document climate changes over the last 1,000 years, and contribute to a growing body of evidence that environmental conditions on the Third Pole, along with the rest of the world, have changed significantly in the last century,” Thompson said. “Generally, the higher the elevation, the greater the rate of warming that’s taking place.”

Around the world, hundreds of millions of people depend on high-altitude glaciers for their water supply. The Guliya Ice Cap is one of many Tibetan Plateau ice caches that provide fresh water to Central, South, and Southeast Asia.

“There are over 46,000 mountain glaciers in that part of the world, and they are the water source for major rivers,” Thompson said.

In September and October of 2015, the team ventured to Guliya and drilled through the ice cap until they hit bedrock. They recovered five ice cores, one of which is more than 1,000 feet long.

The cores are composed of compressed layers of snow and ice that settled on the western Kunlun Mountains year after year. In each layer, the ice captured chemicals from the air and precipitation during wet and dry seasons. Today, researchers analyze the chemistry of the different layers to measure historical changes in climate.

Based on dating of radioactive elements measured by scientists at the Swiss research center ETH Zurich, the ice at the base of the core may be at least 600,000 years old.

The oldest ice core drilled in the Northern Hemisphere was found in Greenland in 2004 by the North Greenland Ice Core Project and was dated to roughly 120,000 years, while the oldest continuous ice core record recovered on Earth to date is from Antarctica, and extends back 800,000.

Over the next few months, the American and Chinese research teams will analyze the chemistry of the core in detail. They will look for evidence of temperature changes caused by ocean circulation patterns in both the North Atlantic and tropical Pacific Oceans, which drive precipitation in Tibet as well as the Indian monsoons. For instance, one important driver of global temperatures, El Niño, leaves its chemical mark in the snow that falls on tropical glaciers.

Ultimately, researchers hope the work will reveal the linkages that exist between ice loss in tropical mountain glaciers and climate processes elsewhere on the planet. Thompson, Yao, and German ecologist Volker Mosbrugger are co-chairing a Third Pole Environment Program to focus on basic science and policy-relevant issues.

“The more we study the different components of the environment of the Third Pole, the better we understand climate change and its linkages among Earth’s three polar regions,” Yao said.

Collaborators on the project include Ellen Mosley-Thompson, Distinguished University Professor of Geography at Ohio State and Director of BPCRC; Mary E. Davis, Emilie Beaudon, Stacy E. Porter, Ping-Nan Lin, M. Roxana Sierra-Hernández and Donald V. Kenny, all of Ohio State; Guangjian Wu and Baiqing Xu of the Institute of Tibetan Plateau Research; and Ninglian Wang of Northwest University and Keqin Duan of Shaanxi Normal University, both in Xian, China.

Funding for the Guliya project was provided by a grant from the National Science Foundation’s Paleo Perspectives on Climate Change Program, the Strategic Priority Research Program of the Chinese Academy of Sciences, and the Frontier Research of the Chinese Academy of Sciences.


ArcticMelt2

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Re: Glaciers worldwide decline faster than ever
« Reply #60 on: June 09, 2019, 08:43:01 PM »
In general, as you can see, even in the place with the oldest ice Northern Hemisphere (at least half a million years!) intensive melting is now underway.

This clearly proves the unprecedented modern warming in the geological history of the Earth.

ArcticMelt2

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Re: Glaciers worldwide decline faster than ever
« Reply #61 on: June 09, 2019, 09:29:59 PM »
https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2018EF001139

Interestingly, it turns out that 80% total mass of the remaining mountain glaciers are located on the mountains of southern Alaska.

This is strange, considering that the oldest mountain ice is found in Tibet.

I haven’t had the chance to read this yet, but I suspect that they are not including the glaciers ofTibet

They write that the amount of ice in Alaska is 10 times greater than in Tibet.

For example, Alaska has the thickest mountain glacier in the world.

https://en.wikipedia.org/wiki/Taku_Glacier

Quote
Using radio-echo soundings and seismic reflections, we measured cross-sections of Taku Glacier, near Juneau, Alaska, to resolve inconsistencies in previous measurements and to understand better the glacier’s dynamics. The maximum thickness is about 1477 m and the minimum bed elevation is about 600 m below sea level, which establishes Taku Glacier as the thickest and deepest temperate glacier yet measured.

Interestingly, 5 years ago it was believed that the mass and area of glaciers in Tibet is almost comparable to Alaska.
https://www.the-cryosphere.net/7/141/2013/tc-7-141-2013.pdf

But in recent years there has been a radical revaluation.
https://www.the-cryosphere.net/13/325/2019/



Quote
Table 6 Percentage ice volume loss, relative to the initial volume (ΔV), and ice loss in millimetres of sea level equivalent (SLE) for the end of the century (2097).

ArcticMelt2

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Re: Glaciers worldwide decline faster than ever
« Reply #62 on: June 09, 2019, 09:58:26 PM »
The table predicts that by the end of this century, Tibet will lose up to 90% of all its ice. Those. It is highly probable that the most ancient ice of the Northern Hemisphere will be destroyed already in this century.

And we will only photos of this amazing place:



https://byrd.osu.edu/research/groups/ice-core-paleoclimatology/projects/china/guliya

Quote
Guliya resembles a "polar" ice cap, is surrounded by vertical 30 to 40 meter ice walls (see photographs).




Tom_Mazanec

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SHARKS (CROSSED OUT) MONGEESE (SIC) WITH FRICKIN LASER BEAMS ATTACHED TO THEIR HEADS

Tor Bejnar

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Re: Glaciers worldwide decline faster than ever
« Reply #64 on: June 19, 2019, 07:24:00 PM »
Typo, Tom:  "before 2030".
Their conclusion is in conflict with the recent From A Glacier's Perspective post on Varied Snowcover Extent Diagnostic of Glacier NP Glacier Climate Response - June 14, 2019
Quote
[That] Three of the glaciers that retain significant snowcover indicates these glaciers are not as vulnerable to warming and will continue to persist until 2050 at least.
(edit for grammar's sake)
Arctic ice is healthy for children and other living things.

gerontocrat

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Re: Glaciers worldwide decline faster than ever
« Reply #65 on: June 19, 2019, 08:43:29 PM »
Typo, Tom:  "before 2030".
Their conclusion is in conflict with the recent From A Glacier's Perspective post on Varied Snowcover Extent Diagnostic of Glacier NP Glacier Climate Response - June 14, 2019
Quote
[That] Three of the glaciers that retain significant snowcover indicates these glaciers are not as vulnerable to warming and will continue to persist until 2050 at least.
(edit for grammar's sake)
Reminds me of "Mars Attacks" after the Martians have wiped out Congress. The President (Jack Nicholson)  addresses the Nation sort of like this..
"Yes, we've lost Congress. But we've still got The Executive and The Judiciary... and two out of three ain't bad".

"No, we ain't gonna lose all the glaciers by 2030.. three might last 'til 2050". Whoopee.
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vox_mundi

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Re: Glaciers worldwide decline faster than ever
« Reply #66 on: June 19, 2019, 09:34:05 PM »
Melting of Himalayan Glaciers has Doubled in Recent Years
https://phys.org/news/2019-06-himalayan-glaciers-years.html

A newly comprehensive study shows that melting of Himalayan glaciers caused by rising temperatures has accelerated dramatically since the start of the 21st century. The analysis, spanning 40 years of satellite observations across India, China, Nepal and Bhutan, indicates that glaciers have been losing the equivalent of more than a vertical foot and half of ice each year since 2000—double the amount of melting that took place from 1975 to 2000. The study is the latest and perhaps most convincing indication that climate change is eating the Himalayas' glaciers, potentially threatening water supplies for hundreds of millions of people downstream across much of Asia.

... Maurer and his colleagues analyzed repeat satellite images of some 650 glaciers spanning 2,000 kilometers from west to east. Many of the 20th-century observations came from recently declassified photographic images taken by U.S. spy satellites. The researchers created an automated system to turn these into 3-D models that could show the changing elevations of glaciers over time. They then compared these images with post-2000 optical data from more sophisticated satellites, which more directly convey elevation changes.

They found that from 1975 to 2000, glaciers across the region lost an average of about 0.25 meters (10 inches) of ice each year in the face of slight warming. Following a more pronounced warming trend starting in the 1990s, starting in 2000 the loss accelerated to about half a meter (20 inches) annually. Recent yearly losses have averaged about 8 billion tons of water, or the equivalent 3.2 million Olympic-size swimming pools, says Maurer. Most individual glaciers are not wasting uniformly over their entire surfaces, he noted; melting has been concentrated mainly at lower elevations, where some ice surfaces are losing as much as 5 meters (16 feet) a year.

Some 800 million people depend in part on seasonal runoff from Himalayan glaciers for irrigation, hydropower and drinking water. The accelerated melting appears so far to be swelling runoff during warm seasons, but scientists project that this will taper off within decades as the glaciers lose mass. This, they say, will eventually lead to water shortages.


Fig. 1 Map of glacier locations and geodetic mass balances for the 650 glaciers.
Circle sizes are proportional to glacier areas, and colors delineate clean-ice, debris-covered, and lake-terminating categories. Insets indicate ice loss, quantified as geodetic mass balances (m w.e. year−1) plotted for individual glaciers along a longitudinal transect during 1975–2000 and 2000–2016. Both inset plots are horizontally aligned with the map view. Gray error bars are 1σ uncertainty, and the yellow trend is the (area-weighted) moving-window mean, using a window size of 30 glaciers.


Open Access: J.M. Maurer el al., "Acceleration of ice loss across the Himalayas over the last 40 years," Science Advances (2019).
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Tor Bejnar

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Re: Glaciers worldwide decline faster than ever
« Reply #67 on: June 19, 2019, 11:48:04 PM »
Quote
"No, we ain't gonna lose all the glaciers by 2030.. three might last 'til 2050". Whoopee.
I agree with the sentiment, although on these threads we are often 'arguing' about when the first BOE will occur (for example), with a difference of opinion within a decade or so. These Montanan glaciers, albeit minor players in the scheme of things (unless you are in Glacier National Park or down stream), have scientists disagreeing on more than 2 decades.
Arctic ice is healthy for children and other living things.

Tor Bejnar

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Re: Glaciers worldwide decline faster than ever
« Reply #68 on: June 20, 2019, 04:04:24 PM »
More from From a Glacier's Perspective:
Arnesenbreen, Svalbard Retreat, Separation and Surge  -  June 20, 2019
Quote
Blaszczyk et al’s (2009) analysis identified 163 Svalbard glaciers that are tidewater with the total length calving ice−cliffs at 860 km for the 2001-2006 period. They observed that 14 glaciers had retreated from the ocean to the land over the last 30–40 year period.
Most of the article is about a pair of glacial fronts that, since 1990, retreated, then surged, then retreated again.

My summary (interpretation/generalization) of the piece I quoted: nearly 8% of Svalbard's glaciers that terminated in the ocean in 1970 no longer terminated in the ocean in 2009.
Arctic ice is healthy for children and other living things.

gerontocrat

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Re: Glaciers worldwide decline faster than ever
« Reply #69 on: June 20, 2019, 04:19:23 PM »
Quote
"No, we ain't gonna lose all the glaciers by 2030.. three might last 'til 2050". Whoopee.
I agree with the sentiment, although on these threads we are often 'arguing' about when the first BOE will occur (for example), with a difference of opinion within a decade or so. These Montanan glaciers, albeit minor players in the scheme of things (unless you are in Glacier National Park or down stream), have scientists disagreeing on more than 2 decades.
Those Montanan glaciers are not going to have a good summer according to the weather people.
Nor will the Alaskan Glaciers or those lumps of ice on land on the islands of the CAA.
"Para a Causa do Povo a Luta Continua!"
"And that's all I'm going to say about that". Forrest Gump
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vox_mundi

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Re: Glaciers worldwide decline faster than ever
« Reply #70 on: July 23, 2019, 06:11:04 PM »
Climate Change Has Claimed Its First Icelandic Glacier
https://www.popularmechanics.com/science/environment/a28470046/okjokull-glacier/

The latest climate change victim is Okjökull, more commonly known as 'Ok,' an Icelandic glacier which scientists from Iceland and Rice University in Houston will memorialize in August with a heartbreaking plaque reading:

Quote
... "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."

The plaque—written by a Icelandic author, Andri Snær Magnason—also reads "415 ppm CO₂," indicating the amount of carbon dioxide in the atmosphere as of May this year. The memorial is a somber reminder of what's to come as we continue emitting high levels of greenhouse gases. Temperatures will continue to soar, summers will be hotter, and we can expect even more glacial melt.

“There are three classes of people: those who see. Those who see when they are shown. Those who do not see.” ― Leonardo da Vinci

Insensible before the wave so soon released by callous fate. Affected most, they understand the least, and understanding, when it comes, invariably arrives too late

vox_mundi

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Re: Glaciers worldwide decline faster than ever
« Reply #71 on: July 26, 2019, 12:16:25 AM »
Underwater Glacial Melting is Occurring at Higher Rates Than Modeling Predicts
https://phys.org/news/2019-07-underwater-glacial-higher.html

Researchers have developed a new method to allow for the first direct measurement of the submarine melt rate of a tidewater glacier, and, in doing so, they concluded that current theoretical models may be underestimating glacial melt by up to two orders of magnitude.

... Most previous research on the underwater melting of glaciers relied on theoretical modeling, measuring conditions near the glaciers and then applying theory to predict melt rates. But this theory had never been directly tested.

To test these models in the field, the research team of oceanographers and glaciologists deployed a multibeam sonar to scan the glacier's ocean-ice interface from a fishing vessel six times in August 2016 and five times in May 2017.

The sonar allowed the team to image and profile large swaths of the underwater ice, where the glacier drains from the Stikine Icefield. Also gathered were data on the temperature, salinity and velocity of the water downstream from the glacier, which allowed the researchers to estimate the meltwater flow.

"We measured both the ocean properties in front of the glacier and the melt rates, and we found that they are not related in the way we expected," Jackson said. "These two sets of measurements show that melt rates are significantly, sometimes up to a factor of 100, higher than existing theory would predict."

The research team found that submarine melt rates were high across the glacier's face over both of the seasons surveyed, and that the melt rate increases from spring to summer.

D.A. Sutherland atUniversity of OregoninEugene, OR el al., "Direct observations of submarine melt and subsurface geometry at a tidewater glacier," Science (2019)
“There are three classes of people: those who see. Those who see when they are shown. Those who do not see.” ― Leonardo da Vinci

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vox_mundi

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Re: Glaciers worldwide decline faster than ever
« Reply #72 on: August 14, 2019, 06:07:51 PM »
New Insight Into Glaciers Regulating Global Silicon Cycling
https://phys.org/news/2019-08-insight-glaciers-global-silicon.html

A new review of silicon cycling in glacial environments, led by scientists from the University of Bristol, highlights the potential importance of glaciers in exporting silicon to downstream ecosystems.

This, say the researchers, could have implications for marine primary productivity and impact the carbon cycle on the timescales of ice ages.

This is because silica is needed by primary producers, such as diatoms (a form of algae that account for up to 35 percent of all marine primary productivity), and these primary producers remove significant amounts of carbon dioxide from the atmosphere, transporting it to the deep ocean.


Open Access: Jade E. Hatton et al, Silicon isotopes in Arctic and sub-Arctic glacial meltwaters: the role of subglacial weathering in the silicon cycle, Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences (2019).
“There are three classes of people: those who see. Those who see when they are shown. Those who do not see.” ― Leonardo da Vinci

Insensible before the wave so soon released by callous fate. Affected most, they understand the least, and understanding, when it comes, invariably arrives too late

vox_mundi

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Re: Glaciers worldwide decline faster than ever
« Reply #73 on: August 15, 2019, 04:55:33 PM »
Heatwave Shuts Down Dog Sled Tours Early on a Glacier Near Skagway, Alaska
https://www.alaskapublic.org/2019/08/14/heatwave-shuts-down-dog-sled-tours-early-on-a-glacier-near-skagway/

Record-breaking temperatures are searing the globe. One spot where the evidence of that heatwave is especially apparent is on a glacier near Skagway. Icefield Expeditions operates a sled dog tour on Denver Glacier above the city. Their hopes for a full season melted in the heat wave ⁠— the snow was gone before August.

“Precipitation and snow pack conditions across Southeast Alaska has been below normal,” said Aaron Jacobs, Senior Hydrologist for the National Weather Service in Juneau. He says regionally the snow pack is less than half of normal.

“But the bigger thing, I think is the temperatures,” Jacobs said. “The trend over the last 10, 20 years is that temperatures have been rising.”

Another piece of the puzzle locally is the pollen that swept through the Upper Lynn Canal this year. A lot of it blew up to the glacier. The dark matter of the pollen absorbs sunlight and it accelerated snow melt.

He has seen low snow years before, but nothing like this. This year, conditions pushed the camp off the Denver glacier altogether. The season that usually runs through September ended in July.

... “We just move way farther up in elevation,” Hayashida said. (... you're going to run out of that elevation thingy pretty soon)
“There are three classes of people: those who see. Those who see when they are shown. Those who do not see.” ― Leonardo da Vinci

Insensible before the wave so soon released by callous fate. Affected most, they understand the least, and understanding, when it comes, invariably arrives too late

Tom_Mazanec

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Re: Glaciers worldwide decline faster than ever
« Reply #74 on: September 11, 2019, 09:07:40 PM »
Swedish mountain loses highest peak title due to global heating
https://www.theguardian.com/world/2019/sep/06/sweden-kebnekaise-mountain-loses-highest-peak-title-global-heating
Quote
The mountain peak known to Swedes as their country’s highest can no longer lay claim to the title due to global heating, scientists have confirmed, as the glacier at its summit shrinks amid soaring Arctic temperatures.

“This is quite a symbol,” said Gunhild Ninis Rosqvist, a Stockholm University geography professor who has been measuring the glacier annually for several years. “A very obvious, very clear signal to everyone in Sweden that things are changing.”
SHARKS (CROSSED OUT) MONGEESE (SIC) WITH FRICKIN LASER BEAMS ATTACHED TO THEIR HEADS

kassy

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Re: Glaciers worldwide decline faster than ever
« Reply #75 on: October 16, 2019, 11:02:58 AM »
A Two-Century-Long Advance Reversed by Climate Change
Mauri Pelto
15 October 2019

In 2008 and 2012, JIRP was at the terminus, creating the map below. There was no change at the east and west side of the margin since 2008, with 55 to 115 m of advance closer to the center. The glacier did not advance significantly after 2013 and did not retreat appreciably until 2018. The Taku Glacier cannot escape the result of three decades of mass losses, with the two most negative years of the record being 2018 and 2019. The result of the run of negative mass balances is the end of a 150+ year advance and the beginning of retreat. Sentinel images from 2016 and 2019 of the two main termini Hole in the Wall Glacier (right) and Taku Glacier (left). The yellow arrows indicate thinning and the expansion of a bare rock trimline along the margin of the glacier. The Hole in the Wall terminus has retreated more significantly with an average retreat of about 100 m.  The Taku main terminus has retreated more than 30 m along most of the front.

...

All other outlet glaciers of the Juneau Icefield have been retreating, and are thus consistent with the dominantly negative alpine glacier mass balance that has been observed globally (Pelto 2017).  Now, Taku Glacier joins the group unable to withstand the continued warming temperatures. Of the 250 glaciers I have personally worked on, it is the last one to retreat. That makes the score: climate change 250, alpine glaciers 0.

https://glacierhub.org/2019/10/15/a-two-century-long-advance-reversed-by-climate-change/

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Tor Bejnar

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Re: Glaciers worldwide decline faster than ever
« Reply #76 on: October 22, 2019, 05:54:05 PM »
A 'perfect example' of a glacier retreating "faster than ever":
Nordenskjold Glacier, South Georgia Retreat Accelerates
From a Glacier's Perspective - October 18, 2019
Quote
In 1989 the glacier terminated at approximately the same location as in 1957. Vegetation extended quite close to the terminus with a minimal trimline or recently deglacated zone evident. ... By 1993 there has been a limited retreat exposing some newly deglaciated unvegetated terrain adjacent to the shoreline and glacier terminus. There was limited additional retreat up to 2000. This is unusual as the neighboring glaciers had all retreated substantially by 2000. By 2016 the glacier had retreated substantially, ~900 m.

Arctic ice is healthy for children and other living things.

Klondike Kat

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Re: Glaciers worldwide decline faster than ever
« Reply #77 on: October 24, 2019, 01:26:42 PM »
A Two-Century-Long Advance Reversed by Climate Change
Mauri Pelto
15 October 2019

In 2008 and 2012, JIRP was at the terminus, creating the map below. There was no change at the east and west side of the margin since 2008, with 55 to 115 m of advance closer to the center. The glacier did not advance significantly after 2013 and did not retreat appreciably until 2018. The Taku Glacier cannot escape the result of three decades of mass losses, with the two most negative years of the record being 2018 and 2019. The result of the run of negative mass balances is the end of a 150+ year advance and the beginning of retreat. Sentinel images from 2016 and 2019 of the two main termini Hole in the Wall Glacier (right) and Taku Glacier (left). The yellow arrows indicate thinning and the expansion of a bare rock trimline along the margin of the glacier. The Hole in the Wall terminus has retreated more significantly with an average retreat of about 100 m.  The Taku main terminus has retreated more than 30 m along most of the front.

...

All other outlet glaciers of the Juneau Icefield have been retreating, and are thus consistent with the dominantly negative alpine glacier mass balance that has been observed globally (Pelto 2017).  Now, Taku Glacier joins the group unable to withstand the continued warming temperatures. Of the 250 glaciers I have personally worked on, it is the last one to retreat. That makes the score: climate change 250, alpine glaciers 0.

https://glacierhub.org/2019/10/15/a-two-century-long-advance-reversed-by-climate-change/

Over 150 years of advance, followed by a mere two years of retreat?  I would like to see this sustained before I make this type of judgment call.

kassy

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Re: Glaciers worldwide decline faster than ever
« Reply #78 on: October 24, 2019, 02:09:28 PM »
Quote
Of the 250 glaciers I have personally worked on, it is the last one to retreat.

I guess the other 249 probably figured in his judgement call and he knows about the local conditions and trends.
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Tor Bejnar

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Re: Glaciers worldwide decline faster than ever
« Reply #79 on: October 24, 2019, 03:12:45 PM »
Quote
The Taku Glacier cannot escape the result of three decades of mass losses
The professional opinion is partially based on mass-loss evidence.  Not all arm-less and leg-less knights fight on.
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kassy

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Re: Glaciers worldwide decline faster than ever
« Reply #80 on: October 24, 2019, 03:44:21 PM »
He might still be able to bite the legs of but the cowards retreat too fast. How apt.  :)

Þetta minnismerki er til vitnis um að við vitum hvað er að gerast og hvað þarf að gera. Aðeins þú veist hvort við gerðum eitthvað.