The Brief

At the bottom of the Earth sits a massive bowl of ice you may know as the West Antarctic ice sheet. Each day, the ocean laps away at its base, slowly eroding the glaciers that line its rim. When they inevitably give in, the sea will begin to fill the basin, claiming the ice for its own and flooding coastlines around the world.

Thwaites Glacier is one of the bulwarks guarding against the collapse of this critical ice sheet, most of which rests below sea level and holds enough ice to raise the ocean by 3.3 meters, or almost 11 feet. Unfortunately, this frosty Goliath, the size of Florida, is also one of the world’s most unstable and fastest-melting glaciers. While glaciologists knew its rate of ice loss was dire, they recently discovered that it’s exposed to far more warming water than previously believed. In a study published this week, scientists using satellite imagery and hydraulic modeling found that warming tidal currents are permeating the massive block of ice at depths as great as 3.7 miles, causing “vigorous melting.”

“We really, really need to understand how fast the ice is changing, how fast it is going to change over the next 20 to 50 years,” said Christine Dow, an associate professor of glaciology at the University of Waterloo and one of the study’s authors. “We were hoping it would take a hundred, 500 years to lose that ice. A big concern right now is if it happens much faster than that.”

As climate change drives global temperatures ever higher, glaciers and ice sheets in polar and mountainous regions inevitably melt. The water and dislodged ice flows into the oceans, causing them to rise. Since 1880, global sea levels have climbed roughly 9 inches, and any sudden increase could be catastrophic for coastal cities like New York, Mumbai, and Shanghai. Low-lying countries like the Marshall Islands and Tuvalu could be submerged entirely.

Thwaites Glacier, often dubbed the “Doomsday Glacier,” already accounts for 4 percent of the planet’s sea level rise and loses 50 billion tons of ice annually. When it collapses, it could raise oceans worldwide by 65 centimeters, or just over 2 feet. “It doesn’t sound like a lot, but if you think of how much ocean water we have in the world, that’s a huge volume,” said Dow.

The study, published in Proceedings of the National Academy of Sciences, found that the pulsing of tides, which raise and lower the ice, allow water to creep further under its shelf and weaken its anchor to the seabed. While the same team observed this phenomenon at Petermann Glacier in Greenland, it had not been recorded in Antarctica. Thwaites has about eight times the amount of ice in contact with the ocean as Petermann.

Using high-resolution satellite images and hydrological data, the study identified high-pressure pockets where the glacier’s surface had been raised, which showed that warm water was flowing under the ice. Previous models had only used the part of the glacier that touches the ocean as the “grounding line” from which to start calculating the potential speed of ice loss from contact with warm, salty water. Now, according to the paper, researchers may have found the missing link in modeling how glaciers change.

“This boundary is a really crucial aspect in geology with respect to the glaciers’ response to a changing climate,” said Bernd Scheuchl, an Earth systems researcher at the University of California-Irvine and an author of the paper. He says a better understanding of the way ocean water can penetrate the base of a glacier can help scientists better predict ice loss across the West Antarctic ice sheet. “The entire region is the gateway to an area that’s well below sea level.”

Predicting the speed of ice loss and sea level rise is no easy task. Ever-shifting factors, like the amount of greenhouse gas emissions, could slow or accelerate global warming, and in turn, the rate that glaciers melt. And modeling glaciers, which are hydrologically dynamic, remote, and difficult to research, is a technological challenge that computers have only recently been able to handle, according to Dow.

Sharon Gray, a marine scientist at the nonprofit Rising Seas Institute, says research breakthroughs like this help the world prepare for and adapt to disappearing coastlines. “It’s never going to be perfect,” she said. “But obviously, the better we can get our models, the better we get our projections that help us plan.”

Given the complexity and uncertainty of modeling, Gray said it’s best to assume seas will rise to the highest predicted level and to prepare for worst-case scenarios. Some high-risk places, like Singapore and the Netherlands, are doing just that and have been investing in infrastructure to meet the challenge. “I think there’s hope and an opportunity in really thinking creatively and trying to wrap our heads around what’s coming and what we can do about it,” she said.

Researchers like Dow and Scheuchl say the best way to protect glaciers is to limit carbon emissions. Although the heat that humanity has already put into the atmosphere will linger for centuries and continue to melt glaciers, curbing the amount the planet warms could buy us time to prepare for, if not prevent, the most extreme outcomes.

“It’s never too late to make some change,” Scheuchl said. “Even if we aren’t able to stop these developments, we can slow things down and lessen their impacts.”

This article originally appeared in Grist at https://grist.org/oceans/scientists-find-miles-of-seawater-beneath-doomsday-glacier/.

Grist is a nonprofit, independent media organization dedicated to telling stories of climate solutions and a just future. Learn more at Grist.org

The Supreme Court hears arguments Monday in an important gun case that has united an array of strange bedfellows, from conservative gun rights groups to liberal civil liberties groups. At issue is a federal law making it a crime for drug users to possess a firearm. It's the same law that was used to prosecute then-President Joe Biden's son for illegal gun possession — only this case involves marijuana use and gun ownership.

The briefs in the case present diametrically different versions of the facts. On one side, the Trump administration portrays Ali Danial Hemani as a drug dealer and someone with terrorist ties and a marijuana habit. Importantly, he is not being prosecuted for any of those offenses, however. Rather, the government has charged Hemani with violating a federal gun law that bars people with drug addiction from possession of firearms, a crime punishable by up to 15 years in prison.

The 5th U.S. Circuit Court of Appeals threw out the indictment, declaring that the federal law violates Hemani's Second Amendment right to own a gun.

The Justice Department appealed to the Supreme Court, arguing that because Hemani admitted to FBI agents that he used marijuana several times a week, he is a "persistent" drug user, thus rendering illegal the possession of the gun he bought legally and keeps securely in his home.

Hemani's lawyer, law professor Naz Ahmad of the City University of New York, paints a very different picture of her client. Hemani, she notes, was born and raised in Texas, "attended high school there, played on the high school football team, attended the University of Texas at Arlington, was an honor student there" and is "a really valued member of his local religious community."

"The Second Amendment doesn't support disarming and prosecuting somebody for mere possession of a firearm if they happen to have used marijuana occasionally," she says.

"That's a mismatch," she adds, especially at a time when 40 states, to one degree or another, have legalized marijuana use.
 
If the court rules against Hemani, she says, "the statute could apply to anybody. It could apply to somebody who uses like a marijuana sleep gummy."

The Trump administration's advocate, Solicitor General D. John Sauer, acknowledges that under the Supreme Court's landmark gun decision four years ago, the government has a heavy burden to show that modern-day gun laws are analogous to laws in place at the nation's founding. But he contends that the statute used to prosecute Hemani is both justified and analogous to founding-era laws and practices.

Specifically, in his Supreme Court brief, Sauer points to the harsh punishments imposed during the founding era on "habitual drunkards." And he contends that both Congress and the states have restricted firearm possession by illegal drug users "for as long as that social evil has plagued America."

That said, for the most part, the case seems to have united groups from left to right, from civil liberties groups to gun rights advocates.

"It's outrageous that they tried to get him on a marijuana gun charge," says Aidan Johnston, director of federal affairs for Gun Owners of America. He contends that the government is seeking to criminalize conduct that was widely tolerated at the founding.

"It was the universal custom of founding-era militias to imbibe," he notes, adding that Thomas Jefferson and other famous Americans "possessed firearms while being users of drugs ranging from opium to cocaine."

At the opposite end of the ideological spectrum are a variety of gun-safety groups that fear that if Hemani wins his case, it could gouge a hole in the existing system of national background checks.

Under the current system, dealers are required to first clear the sale by submitting the buyer's name to the FBI's National Instant Criminal Background Check System. The hitch is that there is a very small window in which to complete the check — just three days. And gun-safety groups say that anything that makes the rules more complicated and unclear could really screw up the system.

"We're saying" to the court, "whatever you do, it's essential that you keep the rules clear so that in that short window, federal agencies can give a quick answer to the dealers," says Douglas Letter of the Brady Center to Prevent Gun Violence. 

An adverse ruling, he says, would mess up the criminal background check process. That, in turn, would result in "so many, particularly women and children, who will die if that kind of a system is not in place."

A decision in the case is expected by summer.
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Longtime administrator Andres Chait addressed the public as acting superintendent of Los Angeles Unified School District for the first time Monday.

“ We remain committed to academic excellence and student wellbeing,” he said ahead of a closed board meeting to discuss his employment and ongoing labor negotiations with district unions. “Our core values remain unchanged. I know transitions can create uncertainty, but our district is strong.”

Chait has worked for the district for nearly three decades, most recently as chief of school operations. His responsibilities included overseeing school safety, athletics and the district’s office of emergency management.

The LAUSD board voted unanimously Friday to place Superintendent Alberto Carvalho on paid administrative leave “pending investigation,” and appointed Chait in his stead. FBI agents searched Carvalho’s home in San Pedro and district office Wednesday.

A justice department spokesperson said the agency had a court-authorized warrant but declined to provide additional details. The reason for the searches is unknown.

Listen to Chait's full comments

This story was originally published by CalMatters. Sign up for their newsletters.

When a possible measles case is identified in California, a phone rings at the local health department and the clock starts ticking.

Laboratory workers need to process samples as soon as possible to confirm the case. And a public health nurse must call the patient to find out where they’ve been and who they’ve been in contact with recently.

If test results are positive, the communicable disease team has 72 hours or less to identify anyone who has been exposed and may be at high risk of infection or serious illness. Those people must quarantine or take a dose of a post-exposure prophylaxis to prevent spread. For the next 21 days nurses will monitor the group for symptoms.

Measles is the most contagious vaccine-preventable viral infection in the world, and California is fighting multiple outbreaks. In a room where one person is infected, nine out of 10 unvaccinated people will also contract the disease. The viral particles also linger in the air long after the contagious person leaves, risking exposure to those who enter the room up to two hours later.

“That’s ridiculously infectious,” said Dr. Sharon Balter, director of acute communicable disease control with Los Angeles County public health. “It balloons very quickly, and because measles spreads very fast we have to get on it right away. We can’t say we’ll wait until tomorrow.”

California has a high enough vaccination rate — about 95% of kindergarteners — to provide herd immunity against measles, but throughout the state pockets of unvaccinated communities drive outbreaks, experts say.

Shasta and Riverside counties are working to contain localized outbreaks. These are the first measles outbreaks in the state since 2020 and are happening at a time when health departments have less money and fewer staff than in recent years. In total, seven counties have reported a total of 21 measles cases this year, according to the California Department of Public Health.

Throughout the country, 26 states have reported measles cases since the start of the year, including a massive outbreak in South Carolina where officials identified nearly 1,000 cases, mostly among unvaccinated children. It is the largest outbreak since theCenters for Disease Control and Prevention declared measles eradicated more than 25 years ago.

“The United States is experiencing the highest numbers of measles cases, outbreaks, hospitalizations and deaths in more than 30 years, driven by populations with low vaccination rates,” said California Public Health Officer Dr. Erica Pan in a statement earlier this month. “We all need to work together to share the medical evidence, benefits, and safety of vaccines to provide families the information they need to protect children and our communities."

Containment comes with high costs

Investigating any communicable disease is time-intensive and expensive. The first three measles cases reported in L.A. County this year cost an estimated $231,000, according to a health department analysis.

Why does it cost so much? Because a disease investigation often requires a legion of public health nurses, physicians, epidemiologists and laboratory scientists to follow-up with hundreds of contacts, Balter said.

A computer shows an analysis of measles sequencing results at the Los Angeles County Department of Public Health laboratory in Downey on Feb. 26, 2026.

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That includes sometimes visiting homes or exposure sites. For example, a recent exposure at a daycare required nurses to wring urine out of used diapers to test babies for measles. County health workers monitored 246 people who had been exposed to those first three measles cases — and the work is ongoing.

On Feb. 19, the county reported its fourth measles case. All of them were related to international travel. Other cases in California also have primarily been related to travel either internationally or to states where there are outbreaks. An unvaccinated child in Napa County contracted measles in January after traveling to South Carolina.

Riverside County health officials reported one measles case where the child had not traveled recently, and Shasta County health officials suspect their first case could be related to travel in Southern California but are waiting for DNA testing for confirmation.

Orange County reported two travel-related cases this year.

Health departments have fewer resources, more cases

Local health departments rely heavily on federal funding to prevent the spread of infectious diseases, but last year, the Trump administration slashed nearly $1 billion of public health funding from California. This year it attempted to claw back another $600 million from California and three other Democratic states.

Pending lawsuits froze the cuts, but local health departments are treating the money as a lost cause because they cannot bear the financial risk if a judge eventually rules in favor of the Trump administration.

Consequently, health departments closed clinics, terminated programs and laid off dozens of workers.

“What we can do with less is less unfortunately,” Balter said. L.A. county is facing a $50 million shortfall due to federal, state and local cuts and recently closed seven public health clinics.

Health departments are also confronting decreased public confidence: The high-profile questioning of vaccine safety and effectiveness by U.S. Secretary of Health and Human Services Robert F. Kennedy Jr. has complicated public health’s struggle to contain the spread of preventable infections.

California Democratic leaders are aggressively fighting Kennedy’s direction. They sued to block the administration’s new vaccine guidelines, which stripped universal recommendation from seven childhood vaccines. They blame Kennedy and the Trump administration for “dismantling” the Centers for Disease Control and Prevention and stoking fears over debunked claims that vaccines cause autism.

The state also released its own vaccine guidelines and formed an alliance among four western states to share public health information and recommendations.

“Everything including the outbreaks, the financial cuts, the questions from the federal government that are arising are making our work very difficult,” said Dr. Regina Chinsio-Kwong, Orange County public health officer.

Lab Assistant Abraham Jimenez loads blood samples for automated serology testing for measles immunity status at the Los Angeles County Department of Public Health laboratory in Downey on Feb. 26, 2026.

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Lab Assistant Abraham Jimenez loads blood samples for automated serology testing for measles immunity status at the Los Angeles County Department of Public Health laboratory in Downey on Feb. 26, 2026.

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Ariana Drehsler

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Twelve years ago, Orange County was the site of California’s largest measles outbreak in decades. An exposure at Disneyland from an unknown source infected 131 Californians and spread to six states, Canada and Mexico.

The outbreak, which lasted four months, spurred state lawmakers to pass some of the strictest childhood vaccine requirements in the country.

But even a single measles case requires “vast amounts of infrastructure” to contain, Chinsio-Kwong said. On average, the department identifies and monitors 100 exposed people per case. Since the start of last year, Orange County has lost $22 million in federal cuts to public health. The department is trying to protect their communicable disease surveillance work, but it gets harder with every cut.

“We're trying to prioritize our communicable disease control division,” health officer Chinsio-Kwong said. “There are a lot of different federal cuts, but we're putting that as front and center: That has to be saved no matter what.”

Measles spread in unvaccinated groups

Six hundred miles north, Shasta County is grappling with its first measles cases since 2019 and the state’s largest outbreak of the year.

In late January, a sick child visited a health clinic in Redding with measles symptoms that laboratory testing later confirmed. Health officials interviewed 278 people and identified six locations where others were exposed: a restaurant, a church basketball game, a gym, a park, Costco and the clinic.

They also identified seven other cases among family members or neighbors who were in close contact with the child.

It can take 21 days from the time of exposure for measles symptoms to develop. On Feb. 19, just before the end of that period, health officials confirmed a ninth case.

That person didn’t recognize the symptoms and visited several places while contagious, including a school, a church service, a basketball game and a clinic, said Daniel Walker, a Shasta County supervising epidemiologist. Now, the contract tracing process has started over. The communicable disease team expects to interview even more people this time.

All cases have been among children who were unvaccinated or did not know their vaccination status.

“It’s a great time to get immunized, because you can’t know when you’re next going to be exposed…especially because we’re in an outbreak situation,” Walker said.

Supported by the California Health Care Foundation (CHCF), which works to ensure that people have access to the care they need, when they need it, at a price they can afford. Visit www.chcf.org to learn more.

This article was originally published on CalMatters and was republished under the Creative Commons Attribution-NonCommercial-NoDerivatives license.

The U.S. attacks on Iran over the weekend, in conjunction with the Israeli military, marked a stunning new phase in relations between the two countries.
But it is hardly the first time Washington and Tehran have clashed politically and militarily.

Here are some key historical moments between the U.S. and Iran.

1953: U.S. helps orchestrate coup that overthrows Mohammad Mosaddegh

Great Britain had controlled Iran's oil industry for decades, but in 1953 Iran's elected prime minister, Mohammad Mosaddegh, nationalized the country's oil sector.

That move prompted Great Britain to appeal to the U.S. for help, and what resulted was a CIA-led campaign to topple Mosaddegh's government. The coup allowed Mohammad Reza Pahlavi, the last shah (or king) of Iran, to consolidate power around himself. (The CIA, long suspected of having a hand in the revolt, officially acknowledged its role in 2013.)

Mosaddegh was imprisoned and later placed under house arrest until his death in 1967. Pahlavi went on to lead Iran for the next two and a half decades, becoming a strong U.S. ally.

1979: Iranian Revolution and U.S. hostage crisis

Iranian opposition leader in exile Ayatollah Ruhollah Khomeini gives a speech as journalists surround him at Roissy airport near Paris on Jan. 31, 1979, before boarding a plane bound for Tehran. Khomeini establishes an Islamic republic in Iran.

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In early 1979, following months of protests by secularists, Islamists and leftists against his autocratic rule, Pahlavi fled Iran and entered the U.S.

The revolution had been led by Ayatollah Ruhollah Khomeini, a Shia cleric who was living in exile near Paris after being expelled by Pahlavi in 1964. Khomeini returned to Iran and oversaw the country's transition to an Islamic republic, becoming Iran's supreme leader. Khomeini established a hard-line theocracy and labeled America the "Great Satan."
In November of that year, a group of Iranian students stormed the U.S. embassy in Tehran and captured 66 Americans.

A U.S. rescue attempt in the spring of 1980 codenamed Operation Eagle Claw, which was approved by President Jimmy Carter, was hampered by mechanical problems, a severe dust storm and a crash that killed eight service members. It failed to secure the release of the hostages.

After 444 days in captivity, the remaining 52 hostages were released on Jan. 20, 1981 — the day President Ronald Reagan was inaugurated.

Early 1980s: The Iran-Contra affair

Reagan's tenure was also marked by a now-infamous transaction with Iran.

Officials in his administration were discovered to have sold weapons to the country in the hope that it would help secure the release of American hostages held in Lebanon by Hezbollah, a militant group allied with Iran.

The Reagan administration used the proceeds of the arms sales to fund the paramilitary Contra rebel group fighting against the socialist Sandinista government in Nicaragua.

Reagan confirmed the story in a 1986 White House press conference and took public responsibility for what's become known as the Iran-Contra affair.

Late 1980s: Tensions in the Persian Gulf

Thousands of people mourn in July 1988 in Tehran, during the funeral service for those who died when an Iranian passenger jet was shot down over the Gulf by the U.S. military.

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Iran and Iraq were engaged in a war since 1980, and toward the end of that decade, Iran began to attack oil tankers belonging to Kuwait and Saudi Arabia, Iraq's financial supporters.

In 1987 the U.S. begins a military campaign known as Operation Earnest Will to protect Kuwaiti tankers.

During that operation in 1988, the U.S. frigate USS Samuel B. Roberts struck an Iranian mine, which punched a 15-foot hole in the hull but did not kill any American sailors.

Still, that incident touched off another military operation called Operation Praying Mantis, in which U.S. forces retaliated for the explosion by attacking several Iranian oil platforms.

Also in 1988, the U.S. Navy shot down the civilian Iran Air Flight 655, killing all 290 people on board. U.S. forces mistook the plane for an Iranian fighter jet.

2015: Obama inks the Iranian nuclear deal

The U.S. reached a deal with Iran and five other world powers to curb Iran's nuclear capabilities in exchange for the removal of some punishing United Nations sanctions.

The deal allowed Iran to continue enriching uranium for civilian energy purposes, but President Barack Obama argued that it would curb the country's ability to create a nuclear bomb. Iran also agreed to increased inspections of its nuclear facilities.

In 2018, Trump during his first term pulled the U.S. out of the Iran nuclear deal and reimposed sanctions on Iran.

The Biden administration held indirect talks with Iran, and when Trump returned to office in 2025 he signed an executive order with the goal of exerting "maximum" pressure on Iran to end its nuclear weapons ambitions.

2020: U.S. drone strike kills Maj. Gen. Qassem Soleimani

A major recent development in U.S.-Iran relations occurred not in Iran itself but in neighboring Iraq.

Just a few days into 2020, U.S. forces launched a drone strike near the Baghdad International Airport and killed Maj. Gen. Qassem Soleimani, among others.

Soleimani, who led an elite branch of Iran's Islamic Revolutionary Guard Corps known as the Quds Force, was seen as one of the country's most influential officials.

Khamenei responded at the time that "harsh retaliation is waiting" for the U.S. Several days later, Iran fired at least a dozen ballistic missiles at two military bases in Iraq that house U.S. troops. The Pentagon said the following month that 109 U.S. troops suffered brain injuries in the strikes.

2025: U.S. and Israel strike Iranian nuclear sites

In June, the U.S. and Israeli militaries launched a dramatic assault on several Iranian nuclear sites. For the U.S., the military escalation followed what had largely been a diplomatic effort to deter Tehran from pursuing a nuclear weapon.

Trump said in a speech from the White House that the goal of the operation was to scuttle Iran's nuclear enrichment capabilities.

"Tonight, I can report to the world that the strikes were a spectacular military success. Iran's key nuclear enrichment facilities have been completely and totally obliterated," Trump said, though there are questions about exactly how much damage was dealt.

The attacks came roughly two months after the U.S. and Iran began a new round of talks to renegotiate a deal concerning Iran's nuclear program.

In March, Director of National Intelligence Tulsi Gabbard had said that U.S. intelligence believes Iran "is not building a nuclear weapon and Supreme Leader Khamenei has not authorized the nuclear weapons program that he suspended in 2003."

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