Tag Archives: ice

Global ice sheets melting at ‘worst-case’ rates: UK scientists | Climate News

Rate of loss rose from 0.8 trillion tonnes per year in the 1990s to 1.3 trillion tonnes per year by 2017, with potentially disastrous consequences.

The rate at which ice is disappearing across the world matches “worst-case climate warming scenarios”, UK scientists have warned in new research.

A team from the universities of Edinburgh, Leeds and University College London said the rate at which ice is melting across the world’s polar regions and mountains has increased markedly in the last 30 years.

Using satellite data, the experts found the Earth lost 28 trillion tonnes of ice between 1994 and 2017.

The rate of loss has risen from 0.8 trillion tonnes per year in the 1990s to 1.3 trillion tonnes per year by 2017, with potentially disastrous consequences for people living in coastal areas, they said.

“The ice sheets are now following the worst-case climate warming scenarios set out by the Intergovernmental Panel on Climate Change (IPCC),” said Thomas Slater, a research fellow at Leeds University’s Centre for Polar Observation and Modelling.

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

Input from the United Nations’ IPCC has been critical to forming international climate change strategies, including the 2015 Paris Agreement under which the majority of greenhouse-gas emitting nations agreed to take steps to mitigate the effect of global warming.

The universities’ research, published in the European Geosciences Union’s journal The Cryosphere, was the first of its kind to use satellite data.

It surveyed 215,000 mountain glaciers around the globe, polar ice sheets in Greenland and Antarctica, ice shelves floating around Antarctica and sea ice drifting in the Arctic and Southern Oceans.

Losses in Artic, Antarctic

The survey found the largest losses in the last three decades were from Arctic Sea ice and Antarctic ice shelves, both of which float on the polar oceans.

While such ice loss does not directly contribute to sea rises, its destruction does stop the ice sheets reflecting solar radiation and thus indirectly contributes to rising sea levels.

“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,” said Isobel Lawrence, a research fellow at the University of Leeds

“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,” she added.

An earlier study published in the Proceedings of the National Academy of Sciences journal based in the United States estimated that global sea levels could rise by two metres (6.5 feet) by the end of this century due to global warming and greenhouse emissions.

The report also said that in the worst-case scenario, global temperatures would warm by more than five degrees Celcius (nine degrees Fahrenheit), causing the water to rise, displacing millions of people living in coastal areas.

Another study, published in 2019 by the US-based Climate Central said that up to 300 million people may be affected by devastating flooding by 2050, about three times more than previously estimated. The number could go up to 630 million by 2100.

The study warned that key coastal cities such as India’s Mumbai, China’s Shanghai and Thailand’s Bangkok could be submerged over the next 30 years.

An estimated 237 million people threatened by rising sea waters live in Asia alone, the research said.



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Substance found in Antarctic ice may solve a martian mystery | Science

Sunlight shines on the snow-capped peaks of the Gerlache Strait in Antarctica.

Andrew Peacock/iStock.com

Researchers have discovered a common martian mineral deep within an ice core from Antarctica. The find suggests the mineral—a brittle, yellow-brown substance known as jarosite—was forged the same way on both Earth and Mars: from dust trapped within ancient ice deposits. It also reveals how important these glaciers were on the Red Planet: Not only did they carve valleys, the researchers say, but they also helped create the very stuff Mars is made of.

Jarosite was first spotted on Mars in 2004, when the NASA Opportunity rover rolled over fine-grained layers of it. The discovery made headlines because jarosite needs water to form, along with iron, sulfate, potassium, and acidic conditions.

These requirements aren’t easily satisfied on Mars, and scientists began to theorize how the mineral could have become so abundant. Some thought it may have been left behind by the evaporation of small amounts of salty, acidic water. But the alkaline basalt rocks in Mars’s crust would have neutralized the acidic moisture, says Giovanni Baccolo, a geologist at the University of Milan-Bicocca and lead author on the new study.

Another idea was that the jarosite was born within massive ice deposits that might have blanketed the planet billions of years ago. As ice sheets grew over time, dust would have accumulated within the ice—and may have been transformed into jarosite within slushy pockets between ice crystals. But the process had never been observed anywhere in the Solar System.

On Earth, jarosite can be found in piles of mining waste that have been exposed to air and rain, but it’s not common. No one expected to find it in Antarctica, and Baccolo wasn’t hunting for it. Instead, he was searching for minerals that might indicate ice age cycles within the layers of a 1620-meter-long ice core, which record thousands of years of Earth’s history. But in the core’s deepest ice, he came across strange dust particles that he thought might be jarosite.

To confirm the mineral’s identity, Baccolo and his collaborators measured how it absorbed x-rays. They also examined grains under powerful electron microscopes, confirming it was jarosite. The particles were also noticeably cracked and devoid of sharp edges, a sign that they had formed and eroded from chemical assaults in pockets within the ice, the researchers report this month in Nature Communications.

The work suggests jarosite forms the same way on Mars, says Megan Elwood Madden, a geochemist at the University of Oklahoma who was not involved with the research. But she wonders whether the process can explain the huge abundance of jarosite on Mars. “On Mars, this is not just some thin film,” she says. “These are meters-thick deposits.”

Baccolo concedes that the ice core contained only small amounts of jarosite, particles smaller than an eyelash or a grain of sand. But he explains that there’s much more dust on Mars than in Antarctica, which only receives small amounts of airborne ash and dirt from northern continents. “Mars is such a dusty place—everything is covered in dust,” Baccolo says. More ash would favor more jarosite formation under the right conditions, he says.

Baccolo wants to use Antarctic cores to investigate whether ancient martian ice deposits were cauldrons for the formation of other minerals. He says jarosite shows how glaciers weren’t just land carving machines, but might have contributed to Mars’s chemical makeup. “This is just the first step in linking deep Antarctic ice with the martian environment.”

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This Ice Cube Makes a New Ice Loss Study Terrifying Real

That’s one big cube.
Graphic: Planetary Visions

We talk about ice a lot here on Earther—or more specifically, the growing absence of it. A new study puts what’s happening to the planet in striking perspective. While I can tell you the results show 1.2 trillion tons of ice disappeared every year since 1994, it’s a lot easier to grasp as a visual.

That cube of ice up there towers 6.2 miles (10 kilometers) into the sky like a sunshade over Manhattan and stretches over a huge swath of New Jersey, from Newark Airport to Jersey City. That’s how much we’ve lost to burning fossil fuels on average per year over the past two decades. The skyscrapers of the Financial District and Midtown are toothpicks. More ominously, the cube is getting bigger as ice loss accelerates.

The ice cube illustration is tied to a study published in the Cryosphere on Monday that looks at, uh, the state of the cryosphere. A team of scientists from across the UK used satellite measurements and climate models to explore what’s happening to every nook and cranny of ice around the globe. While most studies focus on either sea ice or ice on land, the new paper looks at both to give us a better understanding of how much ice has melted due to climate change.

“There has been a huge international effort to study individual regions, such as glaciers spread around the planet, the polar ice sheets in Greenland and Antarctica, the ice shelves floating around Antarctica, and sea ice drifting in the Arctic and Southern oceans,” Tom Slater, the study’s lead author and ice researcher at the University of Leeds, said in an email. “We felt that there was now enough data to be able to combine these efforts and examine all the ice being lost from the planet.”

The results show Arctic sea ice is the fastest-disappearing ice on the planet. A staggering 7.6 trillion tons have turned to liquid from 1994 to 2017, the period for which the study had data. That was followed by Antarctic ice shelves, which have seen 6.5 trillion tons of ice vanish, sometimes in catastrophic fashion. The most recent example is Iceberg A68, a Delaware-size piece of ice that ripped off the Larsen C ice shelf in 2017 and has since wandered the Southern and Atlantic oceans. It most recently had a near run-in with an ecologically sensitive island.

But other, more insidious forms of ice shelf drama are afoot. The study doesn’t just look at ice area; it also looks at ice volume. And the most shocking impacts on ice shelves are happening beneath the surface. Ice shelves jut out over the ocean, holding back glaciers on ice sheets on land. But in West Antarctica, satellite and direct observations show warm water has been eating away at ice shelves and could eventually cause them to collapse. If that happens, sea level rise will accelerate and won’t stop for centuries; the ice in West Antarctica could raise seas by more than 10 feet (3 meters).

Glaciers on land in Alaska, the Himalayas, and elsewhere are also major drivers of sea level rise, as are the glaciers and ice sheets of Greenland. They’re all disappearing at an alarming rate. The threat of water loss in regions that rely on glacier and snowmelt is certainly an acute concern. So, too, is the disappearance of sea ice and its impact on traditional ways of life in the Arctic. And incremental but quickening sea level rise can play out in dramatic fashion when hurricanes roar ashore, pushing storm surge farther inland thanks to the climate change-driven boost. Perhaps most ominously, the melt is just a tiny aspect of the changes happening.

“We found that it took only about 3% of the excess heat created by greenhouse gas emissions to melt all this ice, a surprisingly small amount of energy to melt such a large amount of ice, which has a disproportionately large effect on our environment,” Slater said.

In that light, the giant ice cube from hell is showing just a tiny portion of the impact of human activities on the planet.

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World’s Ice Is Melting Faster Than Ever, Climate Scientists Say

From Antarctica to the Arctic, the world’s ice is melting faster than ever, according to a new global satellite survey that calculated the amount of ice lost from a generation of rising temperatures.

Between 1994 and 2017, the Earth lost 28 trillion metric tons of ice, the survey showed. That is an amount roughly equivalent to a sheet of ice 100 meters thick covering the state of Michigan or the entire U.K.—and the meltwater from so much ice loss has raised the sea level just over an inch or so world-wide, the scientists said.

“It’s such a huge amount it’s hard to imagine it,” said

Thomas Slater,

a research fellow at the U.K.’s University of Leeds Centre for Polar Observation and Modelling and the lead author of a paper describing the new research. “Ice plays a crucial role in regulating the global climate, and losses will increase the frequency of extreme weather events such as flooding, fires, storm surges and heat waves.”

The paper was published Monday in the European Geophysical Union’s journal the Cryosphere.




Adding up the loss from glaciers, ice shelves, polar ice caps and sea ice, Dr. Slater and his colleagues determined that the rate of global melting has accelerated 65% since the 1990s.

The ice loss has grown from 0.8 trillion tons a year to 1.3 trillion tons a year, driven by rising atmospheric and ocean temperatures resulting from greenhouse gas emissions, the scientists said. Slightly more than half the ice loss occurred in the Northern Hemisphere.

Dr. Slater and a team of eight other scientists from the University of Edinburgh, University College London and a Edinburgh-based climate data company called Earth Wave Ltd. based their findings on 50 studies of ice loss, field measurements and data from 17 satellite missions.

The researchers employed a variety of techniques to reach their conclusions. These included the use of satellite altimeters and gravity sensors to measure the volume and mass of ice on the ground below. They also used satellite imagery of ice shelves and glaciers to detect changes over the years.

“It’s a reminder that dangerous climate change is already here, in this case in the form of melting ice, rising sea level and the inundation of our coastlines,” said

Michael Mann,

a Pennsylvania State University climatologist and author of “The New Climate War.” He wasn’t involved in the research.

The new research comes as the U.S. moved last week to rejoin the Paris Agreement, an international climate accord designed to limit greenhouse-gas emissions by 2050 and keep the rise in global temperature to no more than 3.6 degrees Fahrenheit (2 degrees Celsius), compared with preindustrial levels.

Former President

Trump

officially withdrew from the accord last year after vowing to do so for several years.

The average global temperature has risen about 2 degrees Fahrenheit since the 1880s, when systematic record-keeping began, according to the National Aeronautics and Space Administration.

Last week, NASA and the European Union’s Copernicus Climate Change Service announced that Earth’s average global surface temperature in 2020 tied 2016 as the warmest year on record.

Independent studies by the National Oceanic and Atmospheric Administration and a private climate-analysis group called Berkeley Earth found that 2020 was slightly colder than 2016 but warmer than every other year since 1850.

All told, the past seven years have been the warmest in the modern record, according to NASA.

“It’s important that we keep up with the big picture for ice because the story there is very dramatic, despite the possibility that one glacier here or there might be doing something different,” said climate scientist

Gavin Schmidt,

director of the NASA Goddard Institute for Space Studies in New York.

Write to Robert Lee Hotz at sciencejournal@wsj.com

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Antarctica bombshell: NASA baffled after snapping ‘something rising above ice’  | Science | News

The frozen desert serves as a scientific haven for more than 1,000 researchers around the year, who monitor climate change and study Earth’s history. Its barren landscape gives them access to an unspoilt world, where they can complete their research, despite temperatures dropping to as low as -90C. The conditions in parts of the region are so harsh that scientists rarely visit them, instead using satellite data to complete their work.

However, the Science Channel revealed in its ‘What on Earth?’ series how one image – appearing to show something had crash-landed – left experts scratching their heads.

Aviation journalist Joe Pappalardo said: “To me, it looks like something landed there extremely quickly and skated to a halt.

“Maybe something had crashed.

“When you think about something crashing in that part of the world you think about the worst air disaster in New Zealand’s history.”

The series detailed the devastating events of the Mount Erebus disaster.

The narrator said: “The crash theory gains traction when investigators discover the image was taken close to the site of the world’s most catastrophic aviation accidents.

“At 7.21am on November 28, 1979, Air New Zealand flight 901 takes off from Auckland Airport on a sightseeing tour of Antarctica. 

“The crew report clear weather and good visibility.

“But as the plane nears Mount Erebus a strange and terrifying optical illusion known as a whiteout deceives the two pilots.”

READ MORE: Antarctica bombshell: Satellite snapped 400ft ‘manmade’ formation in ‘untouched’ region

“But if we look at this object over here, this little rock shows the shadow – it is an elevated feature.”

And the narrator detailed how this theory was soon supported by NASA.

He added in 2017: “The shadow indicates it not a depression in the ice, but something rising above it.

“NASA scientists Dr Kelly Brunt travels to the remote feature.

“She finds a seven-mile-long wall of jagged ice protruding from the frozen seas of McMurdo Sound.

“It is a rare type of glacier feature created by millions of tonnes of ice flowing from the base of Mount Erebus into the frozen seas.”



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Capitals’ Ilya Samsonov tests positive for coronavirus; Ovechkin, two others remain off the ice – The Washington Post

  1. Capitals’ Ilya Samsonov tests positive for coronavirus; Ovechkin, two others remain off the ice The Washington Post
  2. Alex Ovechkin, 3 others on COVID-19 absence list as NHL fines Washington Capitals $100K for violations of protocols ESPN
  3. Caps will ‘have to move forward’ after breaking COVID protocol, Ovechkin among absences | NBC Sports NBC Sports
  4. Eklund – Ovechkin, Samsonov, Orlov, Kuznetsov Should be Quarantined. No Pay. Buzz@1 Hockeybuzz.com
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Juno maps water ice across northern Ganymede

Jupiter’s moon Ganymede is the largest planetary satellite in the solar system. It’s also one of the most intriguing: Ganymede is the only moon with its own magnetic field, it is the most differentiated of all moons, and it likely possesses a subsurface ocean of liquid water. It was studied by the early Jupiter flybys made by the Pioneer and Voyager spacecraft, but our understanding today rests largely on observations made by NASA’s Galileo orbiter from 1995 to 2003.

Mura et al. now report some of the first in situ observations of Ganymede since the end of the Galileo mission. They used the Jovian Infrared Auroral Mapper (JIRAM) on board NASA’s Juno spacecraft to take images and spectra of the moon’s north polar region. On 26 December 2019, Juno passed Ganymede at a distance of about 100,000 kilometers, enabling JIRAM to map this region at a spatial resolution of up to 23 kilometers per pixel.

As Juno flies past Ganymede, the spacecraft can observe physical locations on the moon’s surface from a variety of angles. By comparing the brightness of these regions across a range of observation and illumination geometries, the authors developed a photometric model for Ganymede’s surface reflectance. They observed that wavelength-dependent reflectance relationships sometimes break down in the vicinity of relatively fresh craters, perhaps because of a larger average size of ice grains in these regions.

Combining their model with spectral observations of the 2-micrometer water ice absorption band allowed the authors to map the distribution of water ice in the north polar region. Where these estimates overlapped with maps derived from Earth-based telescopic observations, the researchers found largely good agreement. This congruence enabled them to extend the global water ice map for Ganymede to much more northerly latitudes.

Observations in other spectral bands also revealed the presence of nonwater chemical species on the surface of Ganymede, including possible detections of hydrated magnesium salts, ammonia, carbon dioxide, and a range of organic molecules.


NASA Juno takes first images of jovian moon Ganymede’s north pole


More information:
A. Mura et al. Infrared Observations of Ganymede From the Jovian InfraRed Auroral Mapper on Juno, Journal of Geophysical Research: Planets (2020). DOI: 10.1029/2020JE006508

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