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Thwaites Glacier won’t collapse like dominoes as feared, study finds, but that doesn’t mean the ‘Doomsday Glacier’ is stable

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theconversation.com – Mathieu Morlighem, Professor of Earth Sciences, Dartmouth College – 2024-08-21 13:00:03

The calving front of Thwaites’ ice shelf. The blue area is light reflecting off ice below the water.
James Yungel/NASA Icebridge

Mathieu Morlighem, Dartmouth College

Antarctica’s Thwaites Glacier got its nickname the “Doomsday Glacier” for its potential to flood coastlines around the world if it collapsed. It is already contributing about 4% of annual sea-level rise as it loses ice, and one theory suggests the glacier could soon begin to collapse into the ocean like a row of dominoes.

But is that kind of rapid collapse really as likely as feared? A new study of Thwaites Glacier’s susceptibility to what’s known as marine ice cliff instability offers some hope. But the findings don’t mean Thwaites is stable.

Polar scientist Mathieu Morlighem, who led the study, explains the results.

Why is the Thwaites Glacier so important?

Thwaites Glacier drains a huge area of Antarctica’s ice sheet – about 74,000 square miles (192,000 square kilometers), an expanse bigger than Florida. If a snowflake falls within that drainage system, it will eventually end up as part of an iceberg in the ocean off Thwaites.

What we are seeing with Thwaites Glacier right now is a disaster in slow motion.

The bedrock under Thwaites Glacier sits below sea level and slopes downward going inland, so the glacier gets deeper toward the interior of the ice sheet. Once the glacier begins losing more ice than it gains from new snowfall and starts to retreat, it’s very hard to slow it down because of this slope. And Thwaites is already retreating at an accelerating rate as the climate warms.

A cross section shows an ice shelf starting to float at the end of a glacier and how the bedrock below slopes inward toward the center of the ice sheet
A cross-section showing an ice shelf and inward-sloping bedrock.
Kelvinsong via Wikimedia, CC BY-SA

Thwaites Glacier holds enough ice to raise global sea level by more than 2 feet (0.65 meters). Once Thwaites starts to destabilize, it also will destabilize neighboring glaciers. So, what happens to Thwaites affects all of the West Antarctic Ice Sheet, and that affects sea-level rise along coastlines everywhere.

What is marine ice cliff instability?

Marine ice cliff instability is a relatively new concept proposed by scientists in the past decade.

Many of the glaciers around Antarctica have huge floating extensions called ice shelves that buttress the glacier and slow its ice flow into the ocean. With the climate warming, we have seen some of these floating extensions collapse, sometimes very rapidly, in the span of a few weeks or months.

An aerial photo of the tall front of Thwaites' ice shelf, where icebergs calve off into the ocean.
The front of Thwaites’ floating ice shelf is over 200 feet (60 meters) tall in places. It becomes higher closer to land.
James Yungel/NASA Icebridge 2012

If Thwaites’ ice shelf were to collapse, it would expose a very tall ice cliff facing the ocean along its 75-mile (120-kilometer) front. There is only so much force that ice can sustain, so if the cliff is too tall, it will collapse into the ocean.

Once that happens, a new ice cliff farther back would be exposed, and the new cliff would be even taller because it is farther inland. The theory of marine ice cliff instability suggests that if the cliffs collapse quickly enough, that could have a domino effect of ever-higher ice cliffs collapsing one after the other.

However, no one has observed marine ice cliff instability in action. We don’t know if it will happen, because a lot depends on how quickly the ice collapses.

Watching the Larsen B ice shelf collapse over less than six weeks in 2002. Once the ice shelf was gone, glaciers it had buttressed began flowing several times faster into the ocean. AGU.

What did you discover about the risk to Thwaites?

When the theory of marine ice cliff instability was first introduced, it used a rough approximation of how ice cliffs might collapse once the ice shelf was gone.

Studies since then have determined that ice cliffs won’t fail systematically until the ice is about 442 feet (135 meters) high. Even at that point, they would fail more slowly than projected until they became much taller.

We used three high-resolution models to explore what this new physical understanding of ice cliff instability would mean for Thwaites Glacier this century.

Our results show that if Thwaites’ entire ice shelf collapsed today, its ice front would not rapidly retreat inland due to marine ice cliff instability alone. Without the ice shelf, the glacier’s ice would flow much faster toward the ocean, thinning the front of the glacier. As a result, the ice cliffs wouldn’t be as high.

We found that Thwaites would remain fairly stable at least through 2100. We also simulated an ice shelf collapse in 50 years, when the glacier’s grounding line – where its grounded ice meets the ocean – would have retreated deeper inland. Even then, we found that marine ice cliff instability alone would not cause a rapid retreat.

Satellite data shows Antarctica losing ice mass since 2002. The area with the fastest ice loss includes Thwaites Glacier. NASA.

The results call into question some recent estimates of just how fast Thwaites might collapse. That includes a worst-case scenario that the Intergovernmental Panel on Climate Change mentioned in its latest assessment report but labeled as “low likelihood.”

Thwaites is the glacier everyone is worried about. If you model the entire ice sheet, this is where marine ice cliff instability starts and where it propagates far inland. So, if Thwaites isn’t as vulnerable to ice cliff failure as we thought, that’s a good sign for the entire ice sheet.

But marine ice cliff instability is only one mechanism of ice loss. This finding doesn’t mean Thwaites is stable.

What else is causing glaciers to retreat at an accelerating rate?

There are many processes that make the Antarctic ice sheet unstable, some of them very well understood.

Ice-ocean interactions explain most of the recent ice mass loss so far. Antarctica is a very cold place, so atmospheric warming isn’t having a large effect yet. But warm ocean currents are getting under the ice shelves, and they are thinning the ice from below, which weakens the ice shelves. When that happens, the ice streams flow faster because there is less resistance.

Colors show Thwaites Glacier flowing faster as it nears the ocean.
Ocean-bottom water temperatures reach above freezing under parts of the Thwaites ice shelf. Thwaites Glacier is outlined in dashes, with colors showing how fast the ice flows. Ocean areas in gray are too shallow to affect the glacial undersides.
NASA JPL/CalTech

Over the past few decades, the Amundsen Sea sector, where Thwaites and Pine Island glaciers are located, has seen an intrusion of warm water from the Antarctic Circumpolar Current, which has been melting the ice from below.

What does climate change have to do with it?

Antarctica can seem like a faraway place, but human activities that warm the planet – such as burning fossil fuels – are having dramatic effects at the poles. Ice loss contributes to sea-level rise, affecting coastal regions around the world.

People’s choices today will determine how quickly the water rises.The Conversation

Mathieu Morlighem, Professor of Earth Sciences, Dartmouth College

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As Gaza ceasefire takes hold, Israeli forces turn to Jenin – a regular target seen as a center of Palestinian resistance

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theconversation.com – Maha Nassar, Associate Professor in the School of Middle Eastern and North African Studies, University of Arizona – 2025-01-22 17:42:00

Maha Nassar, University of Arizona

Just two days after a shaky ceasefire took hold in the Gaza Strip, Israel on Jan. 21, 2025, launched a large-scale incursion of the Jenin refugee camp in the West Bank.

Soldiers raided hundreds of homes in the West Bank city in what the Israeli military called a “counterterrorism” operation, aiming to reassert control there. Many analysts have suggested the raid is an attempt by Israeli Prime Minister Benjamin Netanyahu to appease far-right members of his coalition who oppose the ceasefire deal.

Whatever the motive, the offensive has been devastating for many of the camp’s residents. The Israeli military has destroyed infrastructure, closed entrances to local hospitals and forcibly displaced about 2,000 families, according to reports on the raids. As it was, life for inhabitants of the densely populated camp – home to some 24,000 Palestinian refugees – was hard. The West Bank director of UNRWA, the U.N. agency overseeing refugees, recently described camp conditions as “nearly uninhabitable.”

The focus of the latest Israeli operation is not new. The Jenin refugee camp, on the western edge of the town of Jenin in the north of the occupied West Bank, has often experienced violence between Israeli soldiers and Palestinian militants.

That violence has escalated since the Oct. 7, 2023, attacks, when Hamas gunmen led an incursion into Israel in which around 1,200 people were killed. The camp has faced repeated large-scale military operations by Israeli forces, including drone strikes, ground raids, and airstrikes that have caused widespread destruction. Meanwhile, Israeli settlers have torched Palestinian cars and properties, with 64 such attacks in the Jenin area alone since Oct. 7, 2023. Last December, the Palestinian Authority, which coordinates with Israel to oversee security in parts of the West Bank, also attacked local militants.

These events have deepened political tensions and worsened the economic and humanitarian crises in the West Bank. According to the U.N., more than a quarter of the 800-plus Palestinians killed in the West Bank since Oct. 7 attack have come from the Jenin district; several Israeli civilians have also been killed in the West Bank during the same period.

As a scholar of Palestinian history, I see this recent episode as the latest chapter in a much longer history of Palestinian displacement and defiance of Israeli occupation. Understanding this history helps explain why the Jenin camp in particular has become a target of Israeli offensives and a center of Palestinian militant resistance.

Camp conditions

Jenin, an agricultural town that dates back to ancient times, has long been a center of Palestinian resistance. During the 1948 Arab-Israeli War, Arab fighters successfully pushed back Israeli attempts to capture the town.

At the end of that war, the town became a refuge for some of the hundreds of thousands of Palestinian refugees who fled or were expelled from lands that became part of Israel. Jenin, along with the hilly interior of Palestine known as the West Bank, was annexed by Jordan.

The U.N. Relief and Works Agency established the Jenin camp in 1953, just west of the city. Since then, the agency has provided basic services to the camp’s residents, including food, housing and education.

Camp conditions have always been difficult. In the early years of the camp, refugees had to stand in long lines to receive food rations, and for decades their cramped homes lacked electricity or running water.

The Jenin camp soon became the poorest and most densely populated of the West Bank’s 19 refugee camps. And given its location near the “Green Line” – the armistice line that serves as Israel’s de facto border – camp residents who were expelled from northern Palestine could actually see the homes and villages from which they were expelled. But they were prevented from returning to them.

The rise of militancy

Since 1967, Jenin, along with the rest of the West Bank, has been occupied by the Israeli military.

The Israeli occupation of Jenin compounded the difficulties of these refugees. As stateless Palestinians, they couldn’t return home. But under Israeli occupation, they couldn’t live freely in Jenin, either. Human rights groups have long documented what has been described as “systematic oppression,” which includes discriminatory land seizures, forced evictions and travel restrictions.

Seeing no other path forward, many of the camp’s young refugees turned to armed resistance.

In the 1980s, groups such as the Black Panthers, which was affiliated with the Palestinian nationalist Fatah organization, launched attacks on Israeli targets in an effort to end the occupation and liberate their ancestral lands. Throughout the first intifada – a Palestinian uprising lasting from 1987 to 1993 – the Israeli army raided the Jenin camp many times, seeking to arrest members of militant groups. In the process, Israeli forces also sometimes demolished family members’ homes and arrested relatives. Such acts of apparent collective punishment reinforced the idea for many Palestinians that the Israeli occupation could only be ended by force.

A group of men in headscarves stand in front of flags and banners. One holds a pistol up in the air.
Members of the militant group Fatah in Jenin in 1991.
Esaias Baitel/Gamma-Rapho via Getty Images)

The Oslo peace process of the 1990s – which consisted of a series of meetings between Israeli government and Palestinian representatives – led some former militants to hope that the occupation could be ended through negotiations instead. But Jenin’s camp residents remained marginalized in the West Bank and sealed off from Israel, seeing little improvement in their lives, even after the transfer of administrative powers from Israel to the Palestinian Authority in 1995.

Independent projects like the The Freedom Theatre provided some relief to the camp’s refugee children, but it was not enough to overcome the grinding poverty or the violence they faced from Israeli soldiers and settlers. By the time the second intifada broke out in 2000, many of the camp’s teenagers joined militant groups. That included Freedom Theatre co-founder Zakaria Zubeidi, who joined the Fatah-affiliated Al-Aqsa Martyrs Brigade. Like the youth of the 1980s, they, too, concluded that only armed resistance would bring an end to the occupation.

A cycle of violence?

In April 2002, the Israeli army invaded the Jenin camp, hoping to put an end to such armed groups. There were fierce clashes between Israeli soldiers and young Palestinian men in the camp, solidifying Jenin’s reputation among Palestinians as “the capital of the resistance.”

The lack of progress on peace talks since then, Israel’s settlement building on occupied land – deemed illegal under international law – and the inclusion of hard-line Israeli politicians in the government have exacerbated resentment in the camp. Polls show Palestinians increasingly support armed resistance.

Seeking to protect the camp from Israeli incursions, in 2021 a group of local residents formed the Jenin Brigades. While its founder was affiliated with Palestinian Islamic Jihad, the group quickly drew in militants from various political factions. Members acquired weapons, patrolled the streets and fought off Israeli military incursions. By 2022, they had declared parts of the camp to be “liberated” from the Israeli occupation.

Seemingly alarmed by the increase in militancy and the stockpiling of weapons in the camp, Israel dramatically stepped up its raids in 2022. It was during such a raid that Palestinian American journalist Shireen Abu Akleh was killed by an Israeli soldier.

On July 3, 2023, the Israeli military again invaded Jenin, withdrawing after two days of heavy aerial bombardment and a ground invasion that killed 12 Palestinians and wounded over 100.

The latest offensive could well surpass that death toll, with at least 10 killed in the first day of fighting. But the militancy associated with the camp was built on decades of resistance and defiance to occupation that Israel has had little success in extinguishing. Similarly this time, I believe, such militancy within the camp will only increase with the latest deaths and destruction.

This article is an updated version of a story that was first published by The Conversation on July 5, 2023.The Conversation

Maha Nassar, Associate Professor in the School of Middle Eastern and North African Studies, University of Arizona

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What is seditious conspiracy, which is among the most serious crimes Trump pardoned?

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theconversation.com – Amy Cooter, Director of Research, Academic Development and Innovation at the Center on Terrorism, Extremism and Counterterrorism, Middlebury – 2025-01-22 15:12:00

The Jan. 6, 2021, storming of the Capitol was the result of a planned conspiracy to disrupt the government, prosecutors alleged.
AP Photo/John Minchillo

Amy Cooter, Middlebury

Several of the highest-profile figures in the Jan. 6, 2021, insurrection were charged with, and convicted of, the crime of seditious conspiracy, which is defined as the act of getting together with other people to overthrow the government. They were among the roughly 1,500 people involved in the insurrection who were pardoned or had their prison sentences commuted by Donald Trump on his first day in office.

Seditious conspiracy is a serious crime of conspiring to overthrow the government or stop its normal functioning. Historically, seditious conspiracy has been difficult to successfully prosecute.

In 2009, for example, a state judge ruled that prosecutors had failed to provide sufficient evidence for members of the Michigan Hutaree militia to go to trial on that charge. Certain militia members had been accused of plotting violence against police officers. While some members faced other charges for their actions, the judge determined that a plot against law enforcement was not sufficient to support charges of attempting to overthrow the government.

In contrast, the U.S. Department of Justice charged 18 people associated with the Jan. 6 attack on the U.S. Capitol with that crime, asserting that they had intended to “oppose by force the lawful transfer of presidential power” or had committed other actions that would undermine the entire system of government.

Of those 18, four pleaded guilty, and 10 were found guilty at trial. The remaining four were found not guilty of seditious conspiracy but were convicted of other crimes that were related to the insurrection.

Capitol entry not required

Oath Keepers militia leader Stewart Rhodes’ seditious conspiracy conviction was especially significant because, unlike some other defendants, Rhodes did not physically enter the Capitol building. He was instead in “the restricted area of Capitol grounds,” according to a Justice Department statement.

His conviction was based in part on his communications, including text messages, both before Jan. 6 and on the day itself. Prosecutors successfully argued that these communications were part of a broader conspiracy to disrupt the election certification by organizing and encouraging others to participate in more direct action.

Two men walk in front of a group of masked men with the Washington Monument in the background.
Proud Boys members Joseph Biggs, left, and Ethan Nordean, right with megaphone, walk toward the U.S. Capitol in Washington, D.C., on Jan. 6, 2021.
AP Photo/Carolyn Kaster

Militias respond to convictions – and clemency

Many observers believed successful prosecutions for these charges sent a strong message that violence against a democratically elected government was not acceptable.

Scholars of militia activity like me saw a period of relative quiet through much of Joe Biden’s presidency, which was, in part, likely due to the consequences the Jan. 6 defendants faced.

Some groups, however, continued social media discussions of their beliefs that the 2020 election had been “stolen,” as Trump continues to falsely claim, and which was used as justification by militia members for their attack. Trump himself said publicly he thought the defendants were unjustly persecuted and promised to pardon them if and when he returned to power.

The full effect that the pardons will have on militia actors and related groups in coming years is uncertain: Will the pardons send the message to all Americans that political violence is acceptable, or at least that it can be overlooked or forgiven if the right political figures are in power?The Conversation

Amy Cooter, Director of Research, Academic Development and Innovation at the Center on Terrorism, Extremism and Counterterrorism, Middlebury

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Ozempic and similar weight loss drugs may lower risk of 42 health conditions, but also pose risks

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theconversation.com – Ziyad Al-Aly, Clinical Epidemiologist, Washington University in St. Louis – 2025-01-22 14:11:00

The research shows the health effects of these drugs are significant and wide-ranging.
Mario Tama via Getty Images News

Ziyad Al-Aly, Washington University in St. Louis

Several years ago, a little-known drug named Ozempic – previously used only to treat diabetes – emerged as a promising new drug for weight management.

The Food and Drug Administration’s approval of Ozempic in 2021 for weight loss treatment ushered in a new era for the class of drugs called glucagon-like peptide-1 agonists, or GLP-1.

Today, GLP-1 drugs, including Wegovy, Mounjaro and Zepbound, have become household names and key tools in the fight against obesity: 1 in 8 American adults say they have used a GLP-1 drug, and forecasts show that by 2030, 1 in 10 Americans will likely be using these medications.

Now, research from my lab and others suggests that GLP-1 drugs could help treat dozens of other ailments as well, including cognitive issues and addiction problems. However, my colleagues and I also found previously unidentified risks.

I am a physician-scientist and I direct a clinical epidemiology center focused on addressing public health’s most urgent questions. My team works to address critical knowledge gaps about COVID-19, long COVID, influenza, vaccines, effectiveness and risks of commonly used drugs, and more.

On Jan. 20, 2025, my team published a study of more than 2.4 million people that evaluated the risks and benefits of GLP-1 drugs across 175 possible health outcomes. We found that these drugs lowered risks of 42 health outcomes, nearly a quarter of the total that we analyzed. These include neurocognitive disorders such as Alzheimer’s disease and dementia, substance use and addiction disorders, clotting disorders and several other conditions.

Unfortunately, we also found that GLP-1 drugs come with significant side effects and increase the risk of 19 health conditions we studied, such as gastrointestinal issues, kidney stones and acute pancreatitis, in which the pancreas becomes inflamed and dysfunctional.

Initially, GLP-1 drugs were developed to treat diabetes.

Cognitive benefits

One of the most important health benefits we found was that the GLP-1 drugs lowered the risk of neurodegenerative disorders, including Alzheimer’s disease and dementia. These findings align with other research, including evidence from preclinical studies showing that these drugs may reduce inflammation in the brain and enhance the brain’s ability to form and strengthen connections between its cells, improving how they communicate with one another. These effects contribute to mitigating cognitive decline.

Two other key studies have shown that patients treated with a GLP-1 drug for diabetes had a lower risk of dementia.

All of these studies strongly point to a potential therapeutic use of GLP-1 drugs in treatment of the cognitive decline. Ongoing randomized trials – the gold standard for evaluating new uses of drugs – are looking at the effects of GLP-1 drugs in early Alzheimer’s disease, with results expected later in 2025.

Curbing addiction and suicidal ideation

GLP-1 drugs have also demonstrated potential in reducing risks of several substance use disorders such as those involving alcohol, tobacco, cannabis, opioids and stimulants. This may be due to the ability of these drugs to modulate reward pathways, impulse control and inflammatory processes in the brain.

The effectiveness of GLP-1 drugs in curbing addictive behavior may explain their spectacular success in treating obesity, a chronic disease state that many have suggested is indeed a food addiction disorder.

Our study demonstrated a reduced risk of suicidal thoughts and self-harm among people using GLP-1 drugs. This finding is particularly significant given earlier reports of suicidal thoughts and self-injury in people using GLP-1 drugs. In response to those reports, the European Medicines Agency conducted a review of all available data and concluded that there was no evidence of increased risk of suicidality in people using GLP-1 drugs.

Now at least two studies, including our own, show that GLP-1 drugs actually reduce the risk of suicidality.

Other benefits

In addition to the well-documented effects of GLP-1 drugs in reducing risks of adverse cardiovascular and kidney outcomes, our study shows a significant effect in reducing risk of blood clotting as well as deep vein thrombosis and pulmonary embolism.

One puzzling finding in our study is the reduced risk of infectious diseases such as pneumonia and sepsis. Our data complements another recent study that came to a similar conclusion showing that GLP-1 drugs reduced risk of cardiovascular death and death due to infectious causes, primarily COVID-19.

This is especially important since COVID-19 is regarded as a significant cardiovascular risk factor. Whether GLP-1 drugs completely offset the increased risk of cardiovascular disease associated with COVID-19 needs to be thoroughly evaluated.

GLP-1 drugs may also be useful in treating fatty liver disease and conditions ranging from asthma to chronic obstructive pulmonary disease, sleep apnea, osteoarthritis, depression and eye disorders.

Some doctors are prescribing GLP-1 drugs to help with fertility issues.

Risks and challenges

Despite their broad therapeutic potential, GLP-1 drugs are not without risks.

Gastrointestinal issues, such as nausea, vomiting, constipation and gastroesophageal reflux disease are among the most common adverse effects associated with GLP-1 drugs.

Our study also identified other risks, including low blood pressure, sleep problems, headaches, formation of kidney stones, and gall bladder disease and diseases associated with the bile ducts. We also saw increased risks of drug-induced inflammation of the kidneys and pancreas – both serious conditions that can result in long-term health problems. These findings underscore the importance of careful monitoring in people who are taking GLP-1 medications.

A significant challenge with using GLP-1 drugs is the high rates at which patients stop using them, often driven by their exorbitant cost or the emergence of adverse effects. Discontinuation can lead to rapid weight gain.

That’s a problem, because obesity is a chronic disease. GLP-1 drugs provide effective treatment but do not address the underlying causes of obesity and metabolic dysfunction. As a result, GLP-1 drugs need to be taken long term to sustain their effectiveness and prevent rebound weight gain.

In addition, many questions remain about the long-term effectiveness and risks of these drugs as well as whether there are differences between GLP-1 formulations. Addressing these questions is critical to guide clinical practice.The Conversation

Ziyad Al-Aly, Clinical Epidemiologist, Washington University in St. Louis

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