Earth’s glaciers and ice sheets are melting. Earth


Image via ESA.

Several studies released this year portray a frightening picture of melting of freshwater ice sheets and glaciers of the Earth, 99% of which are found in Greenland and Antarctica. We summarize three recent studies, and provide sources in this post and links to further reading.

The three studies reported here suggest that the two major Antarctic glaciers are loosening by their restrictions, which melt the ice corresponds to the worst conditions in both Antarctica and Greenland, and that many ice shelves in Antarctica are under rapid destruction. Are unsafe for

A map showing West Antarctica with many locations including snow sheets and mountains.

Pine Island and Thwaites Glacier in the ice sheet of the West Antarctic. Image via antarcticglaciers.org.

Antarctic glaciers are tearing loose. A study led by Geologist TU Delft’s Steph Lermitet in the Netherlands – based on satellite imagery on Antarctica – focuses on two very large, long-broad glaciers: Pine Island Glacier and Thwaites Glacier, sometimes referred to in the media as doomsday glacier is done. The study shows that both glaciers are free from obstacles that have so far impeded their rapid flow towards the sea. Once these restrictions are relaxed, both glaciers can be expected to have a major impact on global sea level rise.

Chris Mooney reports on new study of Thwaites and Pine Island glaciers Washington Post On September 14, 2020. they wrote:

Situated on the banks of the Amundsen Sea in West Antarctica, the vast Pine Island and Thwaites Glacier already contribute about 5% of global sea-level rise. The survival of the Thwaites has been considered so important that the United States and Britain have launched a targeted multimillion-dollar research mission to the glacier. The loss of the glacier can trigger widespread collapse of the West Antarctic ice sheet, with enough ice to eventually raise the ice to about 10 feet (3 m).

New findings – published on 14 September 2020 Proceedings of the National Academy of Science – Satellites come from analysis of images. They show that a naturally occurring buffer system that prevents glaciers from flowing rapidly is breaking, potentially removing more ice in the ocean in the coming years.

Scientists can see that their shear margins – where their floating ice shelves face high levels of friction that disrupt the natural flow of ice, are progressively weakening and in some cases crumbling.

Mooney has also mentioned in his article the fact that – as of September 1, 2020 – the extent of Arctic sea ice was at the second lowest limit to date in the satellite record that began in 1979. And, he writes, last month, Canada lost a large part of its last major Arctic ice shelf. And there is more. Mooney’s article provides an excellent overview and some depth on the subject of melting of freshwater ice on Earth.

Read more from Chris Mooney via Washington Post

Source: Damage Accelerates Ice Shelf Instability and Large Scale Losses at Amundsen Embankment

A young blotch man in a t-shirt.

Geologist Steph Lermit in the Netherlands led the Antarctic ice sheet instability study. Image via LinkedIn.

Lattice sheet of ice with icing from which it floats away.

As it flows, the Pine Island Glacier in Antarctica often cools the icebergs to the Amundsen Sea, a branch of the southern ocean that surrounds Andustica. It is a glacier in the form of a huge iceberg on November 7, 2018. Image via Operation Ice Bridge / NASA Earth Observatory.

The map of Architis with snow in white and the line outside it shows that the area has shrunk.

It is not just Antarctic ice that is melting. The Arctic sea ice limit for August 2020 was 5.08 million square kilometers (1.96 million square miles). The magenta line shows the average range for that month from 1981 to 2010. Map via National Snow and Ice Data Center.

Ice melt corresponds to the worst case scenario. European Space Agency (ESA) In a September 8, 2020 report, a recent study confirms that ice sheets in both Greenland and Antarctica, where ice-loss rates are rising rapidly, are among the worst-case sea-levels of climate change. The increase is matching the Intergovernmental Panel on Scenarios.

The study was published in the peer-review journal Nature climate change On 31 August. It compares ice-sheet mass-balance results from satellite observations with estimates from climate models. ESA explained:

As systematic monitoring of ice sheets began in the early 1990s, Greenland and Antarctica jointly lost 6.4 trillion metric tons of ice between 1992 and 2017 – raising global sea levels by 0.7 inches. [17.8 millimeters]. If these rates continue, ice sheets expect to raise sea level by about 6.7 inches [17 cm] – Exposing an additional 16 million people to annual coastal flooding by the end of the century.

Tom Slater, lead author of the study and climate researcher at the Center for Polar Observation and Modeling at Leander University, commented:

Satellites are our only means of regular monitoring of these vast and remote areas, so they are absolutely critical in providing measurements that we can use to validate the ice sheet model.

Read more about this study through ESA

Source: Ice sheet losses track high-end sea level rise projections

A young man in a windbreaker, glasses.

Tom Slater in the UK, an expert using satellites to study Greenland and Antarctic ice sheets, led the study reflecting the rapid loss of ice on both northern and southern Earths. Image via University of Leeds.

Showing lines growing linearly.

Contribution of Antarctic and Greenland ice sheets at the global sea level according to IMBIE (black) comparing satellite observations and estimates between 1992–2040 (left) and 2040–2100 (right). Image via ESA.

Antarctic ice shelves weak. Here is the final piece of bad news from the Earth Institute of Columbia University, New York. Kevin Krajic, a senior editor there and who blogs on Earth-related topics, reported in a new study on August 26, 2020 that many ice shelves around Antarctica could be unsafe. Soon Destruction if rising temperatures drive water into many fractures that already penetrate their surfaces. Krajic’s report is based on a scientific study published in the peer-reviewed journal NatureUnder the leadership of Ching-Yao Lai at Columbia University’s Lamont-Doherty Earth Observatory. Krajic wrote:

The shelves help slow internal glaciers slide towards the sea, so if they fail, sea levels around the world can rise rapidly…

Ice cabinets are giant tongues of ice floating in the sea around the edges of the continent. Behind them huge glaciers with large land boundaries are constantly pushing towards the sea. But because many shelves are largely confined within giant blocks and lanes, they narrow from the sides and slow down the march of glaciers – somewhat in a narrow hallway with a man covering his arms against the walls , Who is trying to push someone.

But ice shelves experience a competitive strain: they approach the ocean. Satellite observations suggest that, as a result, they diverge; Most are perpendicular with many long fractures that are perpendicular to the direction of stretching. Surface fractures can occur tens of meters deep; Others, formed from below, can penetrate up to hundreds of meters of snow. Some fractures are hundreds of meters wide.

Currently, most shelves are frozen throughout the year, and are stable. But scientists say widespread warming may occur later in the century. And, existing research has shown that even at micro temperature swings, widespread melting can occur. It can send molten water into surface fractures. Such buoyancy would potentially lead to hydrofracturing – a process in which liquid water, heavy with ice, would violently force fractures into open zip, and cause the shelf to disintegrate rapidly.

The new study estimates that 50% to 70% of areas of ice shelves that suppress glaciers are vulnerable to such processes.

Lead author Ching-Yao Lai said:

It is not just about melting, but where it is to melt.

Read more through Prithvi Institute

Source: Antarctica’s vulnerability to melting water fractures on ice shelves

A young dark-haired woman with trees and grass in the background.

Ching-Yao Lai is a fluid mechanics / climatologist at the Earth Institute in New York. He led the study showing the vulnerability of Antarctic ice sheets.

Bottom Line: The three studies mentioned in this post show that two major Antarctic glaciers are loosening over their borders, that the ice melt corresponds to the worst in both Antarctica and Greenland, and that many ice shelves in Antarctica accelerated. Are vulnerable to destruction.

Quick facts about ice sheets and glaciers from the National Snow and Ice Data Center

Deborah Bird

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