ice loss

Antarctic Ice Collapse | Earth Wise

March 2, 2022 By EarthWise Leave a Comment

In Antarctica, a huge chunk of the Larsen B Ice Shelf collapsed suddenly and spectacularly in January.

The Larsen Ice Shelf is located on the northeastern side of the Antarctic Peninsula on the Weddell Sea. It was formed over the course of more than 12,000 years. The Weddell Sea used to be a completely frozen body of water. The famous Ernest Shackleton expedition in 1915 was trapped in its ice. But the Antarctic Peninsula has been steadily warming in recent decades.

The Larsen A Ice shelf collapsed in 1995 and the 1,250-square-mile Larsen B Ice Shelf collapsed in 2002. After that event, a portion of the detached ice shelf refroze in 2011 and was attached to the Scar Inlet Ice Shelf. The refrozen ice was called the Larsen B embayment.

In January, the embayment broke apart, taking with it a portion of the Scar Inlet Ice Shelf. It disintegrated within a matter of days. The combined Larsen Ice Shelves – called A, B, C, and D – once extended along a 1000-mile stretch of the eastern Antarctic Peninsula. Since 1995, it has shrunk from 33,000 square miles to 26,000 square miles.

These ice shelves float on the ocean, so their loss does not actually increase global sea levels. However, the shelves act as dams that hold back glaciers located on the land behind them. The loss of Antarctic ice shelves dramatically increases the rate at which glaciers flow into the sea, and that does increase global sea levels.

Now that the sea ice from the Larsen B embayment is gone, it is likely that there will be additional inland ice losses from the newly exposed glaciers.

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Remnant of Antarctica’s Larsen B Ice Shelf Disintegrates

Photo, posted February 13, 2018, courtesy of NASA/Nathan Kurtz via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

The Threat From Thwaites | Earth Wise

January 20, 2022 By EarthWise Leave a Comment

The Thwaites Glacier in Antarctica is the widest glacier in the world. It is about 80 miles across and in places extends to a depth of about 2,600 to 3,900 feet. The glacier is roughly the size of Florida, and it currently contributes 4% of annual global sea level rise as it continues to retreat from a warming ocean.

The International Thwaites Glacier Collaboration is a team of nearly 100 scientists dedicated to studying the glacier. According to the scientists, Thwaites has doubled its outflow speed within the last 30 years. The glacier in its entirety holds enough water to raise global sea levels by over two feet, which would be catastrophic.

A third of the glacier flows more slowly than the rest because it is braced by a floating ice shelf that is held in place by an underwater mountain. The concern is that the brace of ice slowing the glacier may not last for long.

Beneath the surface, warmer ocean water is attacking the glacier from all angles. The water is melting the ice directly beneath the glacier causing it to lose its grip on the underwater mountain. Massive fractures have formed and are growing.

Warm water is also a threat for what is called the grounding zone, which is the area where the glacier lifts off the seabed. There are many possible scenarios under which there could be a major ice loss from the glacier. It is unclear how quickly it could occur. It might take decades, or it could be centuries. The threat is large enough and real enough that continued observation and research is essential.

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The Threat from Thwaites: The Retreat of Antarctica’s Riskiest Glacier

Photo, posted October 16, 2012, courtesy of J. Yungel / NASA Ice via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Disappearing Mountaintop Glacier Ice | Earth Wise

August 30, 2021 By EarthWise Leave a Comment

A newly released study has found that mountaintop glacier ice in the tropics of all four hemispheres has diminished dramatically over the past 50 years. Among the findings of the study, published in the journal Global and Planetary Change, are that a glacier near Puncak Jaya, in Papua New Guinea, lost about 93% of its ice between 1980 and 2018. Between 1986 and 2019, the area covered by glaciers on top of Mt. Kilimanjaro in Africa decreased by nearly 75%.

The study combined NASA satellite imagery with data from ice cores drilled during field expeditions on tropical glaciers around the world. The combination of measurements demonstrated that climate change is causing these glaciers to disappear and that the ice loss has accelerated in recent years.

The study looked at glacier ice in Kilimanjaro in Tanzania, the Andes in Peru and Bolivia, the Tibetan Plateau and the Himalayas, and ice fields in Papua, New Guinea. Collecting ice cores from these places provides information on the climate in these regions over the centuries and millennia. As snow falls on a glacier each year, it is buried and compressed to form layers that preserve the chemistry of snow, pollutants from the atmosphere, and biological material such as plants and pollen.

Glaciers in the tropics respond more quickly to climate change because they exist in the warmest areas of the world and survive only at very high altitudes. For many of these tropical glaciers, it is too late to prevent their demise. It is not too late to attempt the slow down the buildup of greenhouse gases in the atmosphere that is causing the planet to warm, but we don’t have unlimited time to act.

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Mountaintop glacier ice disappearing in tropics around the world

Photo, posted February 12, 2009, courtesy of Christoph Strassler via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

The Arctic Northeast Passage May Open | Earth Wise

November 12, 2020 By EarthWise Leave a Comment

The Northwest Passage is the sea route between the Atlantic and Pacific oceans through the Arctic Ocean. It goes along the northern coast of North America, traveling though the Canadian Arctic Archipelago. In the past, it was the domain of intrepid explorers like Roald Amundsen. Because of the receding ice in the Arctic, in recent years it has become possible to travel the Northwest Passage by cruise ship.

The Northeast Passage connects the same two oceans along the Arctic coasts of Norway and Siberia. The sustained loss of sea ice is now leading to accessibility of Arctic sea passages through this route.

Compared with the customary route through the Strait of Malacca in Malaysia and the Suez Canal, using the Northeast Passage could reduce the travel distance between Europe and northwest Asia by one-third. This would reduce the expense of transportation and lower environmental pollution. Many Asian countries have a strong strategic and economic interest in Arctic shipping. Russia would gain strong competitive advantages for its liquified natural gas industry.

According to a recent study at the Northwest Institute of Eco-Environment and Resources of the Chinese Academy of Sciences, the continuing warming of the Arctic seas is likely to result in the Northeast Passage being navigable for open water ships by next year and will continue to be increasingly hospitable to marine traffic.

The economic and strategic benefits to the opening of the Northeast Passage are quite clear. What is also clear is that the underlying cause of the opening of the passage – the dramatic loss of Arctic sea ice – is not beneficial to the world at all and is a harbinger of troubling things in our future.

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Arctic Northeast Passage may be Navigable in Near Future

Photo, posted September 24, 2005, courtesy of Paul Downey via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Greenland Glaciers Past The Point Of No Return | Earth Wise

September 18, 2020 By EarthWise Leave a Comment

Forty years of satellite data from Greenland shows that the glaciers on the island have shrunk so much that even if global warming came to an abrupt halt, the Greenland ice sheet would continue to shrink.

This conclusion was published in the journal Communications Earth and Environment by researchers at Ohio State University. According to their study, Greenland’s glaciers have passed a tipping point where the snowfall that replenishes the ice sheet each year can no longer keep up with the ice that is flowing into the ocean from the glaciers.

The study analyzed monthly satellite data from more than 200 large glaciers that drain into the ocean around Greenland. It looked at how much ice breaks off into icebergs or melts from the glaciers into the ocean as well as the amount of snowfall each year that replenishes the glaciers.

Throughout the 1980s and 90s, these two processes were mostly in balance, keeping the ice sheet intact. But the amount of ice being lost each year started to increase steadily around the year 2000 while there was no increase in snowfall. Both processes fluctuate from year to year, but the baseline for ice loss has steadily risen. Before 2000, the Greenland ice sheet had about the same chance of gaining or losing mass each year. At this point, the ice sheet is likely to gain mass in only one out of every 100 years.

Large glaciers in Greenland have retreated about 2 miles since 1985, so that many of them are sitting in deeper water with more ice in contact with warmer water making it harder for glaciers to grow back. At this point, even if the climate reverses its trend, the ice sheet will continue to lose mass.

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Warming Greenland ice sheet passes point of no return

Photo, posted August 27, 2015, courtesy of Joxean Koret via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Ice Melt In Greenland

March 12, 2019 By EarthWise 1 Comment

A new study published in the Proceedings of the National Academy of Sciences warns that Greenland’s ice Is melting much faster than previously thought. The ice loss rapidly accelerated around 2002-2003 and by 2012 the annual loss was nearly four times the rate in 2003.

Most of the new ice melt is in southwest Greenland, a part of the island that wasn’t known to be losing ice that rapidly and is not where most of the large glaciers are in Greenland. The loss is coming from the land-fast ice sheet itself.

Data from NASA satellites and GPS stations scattered around Greenland’s coast shows that between 2002 and 2016, Greenland lost approximately 280 billion tons of ice per year. That is enough melt to cover the entire states of Florida and New York hip deep in meltwater, as well as drowning Washington, D.C. and one or two other small states.

Global warming of just 1 degree Celsius is the main driver behind this massive meltdown of ice. The temperature rise coupled with a negative phase of the North Atlantic Oscillation causes rapid surface melt of the ice sheet during summers. The Oscillation is a natural, irregular change in atmospheric pressure that brings warm, sunny weather to the western side of Greenland during its negative phase.

The Greenland ice sheet is 2 miles thick in some places and contains enough ice to raise sea levels 23 feet if it all melted. The melting Greenland ice is already slowing the Gulf Stream, which is wreaking havoc with European weather. If we don’t get a handle on global temperature rise, things are only going to get worse.

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