Liu Zhenmin also defended Beijing’s own climate efforts as “very ambitious.”

British and Brazilian officials hope for a change of heart after this month’s budget.

Business groups say the laws violate companies' First Amendment rights.

The NYU School of Law’s Institute for Policy Integrity says the costs of deregulation far exceeds the benefits.

AI has fueled a boom in new weather prediction tools, which are starting to replace forecasts that had been generated by supercomputers.

Earth and rocks collapsed on a bus in Khanh Hoa province Sunday night, killing six and trapping many passengers, state media reported.

The operation, which involves dispersing chemicals into clouds, takes place as Iran faces its worst drought in decades.

The nation, a major importer of thermal coal, will join about 60 countries in the Powering Past Coal Alliance.

Feeling thirsty? Why not tap into the air? Even in desert conditions, there exists some level of humidity that, with the right material, can be soaked up and squeezed out to produce clean drinking water. In recent years, scientists have developed a host of promising sponge-like materials for this “atmospheric water harvesting.”

But recovering the water from these materials usually requires heat — and time. Existing designs rely on heat from the sun to evaporate water from the materials and condense it into droplets. But this step can take hours or even days. 

Now, MIT engineers have come up with a way to quickly recover water from an atmospheric water harvesting material. Rather than wait for the sun to evaporate water out, the team uses ultrasonic waves to shake the water out.

The researchers have developed an ultrasonic device that vibrates at high frequency. When a water-harvesting material, known as a “sorbent,” is placed on the device, the device emits ultrasound waves that are tuned to shake water molecules out of the sorbent. The team found that the device recovers water in minutes, versus the tens of minutes or hours required by thermal designs.

Unlike heat-based designs, the device does require a power source. The team envisions that the device could be powered by a small solar cell, which could also act as a sensor to detect when the sorbent is full. It could also be programmed to automatically turn on whenever a material has harvested enough moisture to be extracted. In this way, a system could soak up and shake out water from the air over many cycles in a single day.

“People have been looking for ways to harvest water from the atmosphere, which could be a big source of water particularly for desert regions and places where there is not even saltwater to desalinate,” says Svetlana Boriskina, principal research scientist in MIT’s Department of Mechanical Engineering. “Now we have a way to recover water quickly and efficiently.”

Boriskina and her colleagues report on their new device in a study appearing today in the journal Nature Communications. The study’s first author is Ikra Iftekhar Shuvo, an MIT graduate student in media arts and sciences, along with Carlos Díaz-Marín, Marvin Christen, Michael Lherbette, and Christopher Liem.

Precious hours

Boriskina’s group at MIT develops materials that interact with the environment in novel ways. Recently, her group explored atmospheric water harvesting (AWH), and ways that materials can be designed to efficiently absorb water from the air. The hope is that, if they can work reliably, AWH systems would be of most benefit to communities where traditional sources of drinking water — and even saltwater — are scarce.

Like other groups, Boriskina’s lab had generally assumed that an AWH system in the field would absorb moisture during the night, and then use the heat from the sun during the day to naturally evaporate the water and condense it for collection.

“Any material that’s very good at capturing water doesn’t want to part with that water,” Boriskina explains. “So you need to put a lot of energy and precious hours into pulling water out of the material.”

She realized there could be a faster way to recover water after Ikra Shuvo joined her group. Shuvo had been working with ultrasound for wearable medical device applications. When he and Boriskina considered ideas for new projects, they realized that ultrasound could be a way to speed up the recovery step in atmospheric water harvesting.

“It clicked: We have this big problem we’re trying to solve, and now Ikra seemed to have a tool that can be used to solve this problem,” Boriskina recalls.

Water dance

Ultrasound, or ultrasonic waves, are acoustic pressure waves that travel at frequencies of over 20 kilohertz (20,000 cycles per second). Such high-frequency waves are not visible or audible to humans. And, as the team found, ultrasound vibrates at just the right frequency to shake water out of a material.

“With ultrasound, we can precisely break the weak bonds between water molecules and the sites where they’re sitting,” Shuvo says. “It’s like the water is dancing with the waves, and this targeted disturbance creates momentum that releases the water molecules, and we can see them shake out in droplets.”

Shuvo and Boriskina designed a new ultrasonic actuator to recover water from an atmospheric water harvesting material. The heart of the device is a flat ceramic ring that vibrates when voltage is applied. This ring is surrounded by an outer ring that is studded with tiny nozzles. Water droplets that shake out of a material can drop through the nozzle and into collection vessels attached above and below the vibrating ring.

They tested the device on a previously designed atmospheric water harvesting material. Using quarter-sized samples of the material, the team first placed each sample in a humidity chamber, set to various humidity levels. Over time, the samples absorbed moisture and became saturated. The researchers then placed each sample on the ultrasonic actuator and powered it on to vibrate at ultrasonic frequencies. In all cases, the device was able to shake out enough water to dry out each sample in just a few minutes.

The researchers calculate that, compared to using heat from the sun, the ultrasonic design is 45 times more efficient at extracting water from the same material.

“The beauty of this device is that it’s completely complementary and can be an add-on to almost any sorbent material,” says Boriskina, who envisions a practical, household system might consist of a fast-absorbing material and an ultrasonic actuator, each about the size of a window. Once the material is saturated, the actuator would briefly turn on, powered by a solar cell, to shake out the water. The material would then be ready to harvest more water, in multiple cycles throughout a single day.

“It’s all about how much water you can extract per day,” she says. “With ultrasound, we can recover water quickly, and cycle again and again. That can add up to a lot per day.”

This work was supported, in part, by the MIT Abdul Latif Jameel Water and Food Systems Lab and the MIT-Israel Zuckerman STEM Fund.

This work was carried out in part by using MIT.nano and ISN facilities at MIT.

Nature Climate Change, Published online: 18 November 2025; doi:10.1038/s41558-025-02500-0

Climate change threatens biodiversity, but the transfer of genes between species via hybridization can enhance climate resilience. This research demonstrates that hybrid mountain birds show reduced climate vulnerability, highlighting how maintaining natural gene flow can mitigate extinction risks and is crucial for conserving species with narrow environmental tolerances.

Nature Climate Change, Published online: 18 November 2025; doi:10.1038/s41558-025-02480-1

The authors couple calculations of historical heatwave intensity at present and future global temperatures with exposure–response functions to quantify mortality from extreme heat events in Europe. They project tens of thousands of excess deaths, with limited attenuation from existing adaptations.

Determining the least expensive path for a new subway line underneath a metropolis like New York City is a colossal planning challenge — involving thousands of potential routes through hundreds of city blocks, each with uncertain construction costs. Conventional wisdom suggests extensive field studies across many locations would be needed to determine the costs associated with digging below certain city blocks.

Because these studies are costly to conduct, a city planner would want to perform as few as possible while still gathering the most useful data for making an optimal decision.

With almost countless possibilities, how would they know where to start?

A new algorithmic method developed by MIT researchers could help. Their mathematical framework provably identifies the smallest dataset that guarantees finding the optimal solution to a problem, often requiring fewer measurements than traditional approaches suggest.

In the case of the subway route, this method considers the structure of the problem (the network of city blocks, construction constraints, and budget limits) and the uncertainty surrounding costs. The algorithm then identifies the minimum set of locations where field studies would guarantee finding the least expensive route. The method also identifies how to use this strategically collected data to find the optimal decision.

This framework applies to a broad class of structured decision-making problems under uncertainty, such as supply chain management or electricity network optimization.

“Data are one of the most important aspects of the AI economy. Models are trained on more and more data, consuming enormous computational resources. But most real-world problems have structure that can be exploited. We’ve shown that with careful selection, you can guarantee optimal solutions with a small dataset, and we provide a method to identify exactly which data you need,” says Asu Ozdaglar, Mathworks Professor and head of the MIT Department of Electrical Engineering and Computer Science (EECS), deputy dean of the MIT Schwarzman College of Computing, and a principal investigator in the Laboratory for Information and Decision Systems (LIDS).

Ozdaglar, co-senior author of a paper on this research, is joined by co-lead authors Omar Bennouna, an EECS graduate student, and his brother Amine Bennouna, a former MIT postdoc who is now an assistant professor at Northwestern University; and co-senior author Saurabh Amin, co-director of Operations Research Center, a professor in the MIT Department of Civil and Environmental Engineering, and a principal investigator in LIDS. The research will be presented at the Conference on Neural Information Processing Systems.

An optimality guarantee

Much of the recent work in operations research focuses on how to best use data to make decisions, but this assumes these data already exist.

The MIT researchers started by asking a different question — what are the minimum data needed to optimally solve a problem? With this knowledge, one could collect far fewer data to find the best solution, spending less time, money, and energy conducting experiments and training AI models.

The researchers first developed a precise geometric and mathematical characterization of what it means for a dataset to be sufficient. Every possible set of costs (travel times, construction expenses, energy prices) makes some particular decision optimal. These “optimality regions” partition the decision space. A dataset is sufficient if it can determine which region contains the true cost.

This characterization offers the foundation of the practical algorithm they developed that identifies datasets that guarantee finding the optimal solution.

Their theoretical exploration revealed that a small, carefully selected dataset is often all one needs.

“When we say a dataset is sufficient, we mean that it contains exactly the information needed to solve the problem. You don’t need to estimate all the parameters accurately; you just need data that can discriminate between competing optimal solutions,” says Amine Bennouna.

Building on these mathematical foundations, the researchers developed an algorithm that finds the smallest sufficient dataset.

Capturing the right data

To use this tool, one inputs the structure of the task, such as the objective and constraints, along with the information they know about the problem.

For instance, in supply chain management, the task might be to reduce operational costs across a network of dozens of potential routes. The company may already know that some shipment routes are especially costly, but lack complete information on others.

The researchers’ iterative algorithm works by repeatedly asking, “Is there any scenario that would change the optimal decision in a way my current data can't detect?” If yes, it adds a measurement that captures that difference. If no, the dataset is provably sufficient.

This algorithm pinpoints the subset of locations that need to be explored to guarantee finding the minimum-cost solution.

Then, after collecting those data, the user can feed them to another algorithm the researchers developed which finds that optimal solution. In this case, that would be the shipment routes to include in a cost-optimal supply chain.

“The algorithm guarantees that, for whatever scenario could occur within your uncertainty, you’ll identify the best decision,” Omar Bennouna says.

The researchers’ evaluations revealed that, using this method, it is possible to guarantee an optimal decision with a much smaller dataset than would typically be collected.

“We challenge this misconception that small data means approximate solutions. These are exact sufficiency results with mathematical proofs. We’ve identified when you’re guaranteed to get the optimal solution with very little data — not probably, but with certainty,” Amin says.

In the future, the researchers want to extend their framework to other types of problems and more complex situations. They also want to study how noisy observations could affect dataset optimality.

“I was impressed by the work’s originality, clarity, and elegant geometric characterization. Their framework offers a fresh optimization perspective on data efficiency in decision-making,” says Yao Xie, the Coca-Cola Foundation Chair and Professor at Georgia Tech, who was not involved with this work.

The state's top emergency official also is under discussion to lead FEMA. The agency's acting chief resigned Monday after a six-month stint.

Researchers at MIT Lincoln Laboratory have developed a first-of-its-kind hydrophone built around a simple, commercially available microphone. The device, leveraging a common microfabrication process known as microelectromechanical systems (MEMS), is significantly smaller and less expensive than current hydrophones, yet has equal or exceeding sensitivity. The hydrophone could have applications for the U.S. Navy, as well as industry and the scientific research community.

"Given the broad interest from the Navy in low-cost hydrophones, we were surprised that this design had not been pursued before," says Daniel Freeman, who leads this work in the Advanced Materials and Microsystems Group. "Hydrophones are critical for undersea sensing in a variety of applications and platforms. Our goal was to demonstrate that we could develop a device at reduced size and cost without sacrificing performance."

Essentially an underwater microphone, a hydrophone is an instrument that converts sound waves into electrical signals, allowing us to "hear" and record sounds in the ocean and other bodies of water. These signals can later be analyzed and interpreted, providing valuable information about the underwater environment.

MEMS devices are incredibly small systems — ranging from a few millimeters down to microns (smaller than a human hair) — with tiny moving parts. They are used in a variety of sensors, including microphones, gyroscopes, and accelerometers. The small size of MEMS sensors has made them crucial in various applications, from smartphones to medical devices. Currently, no commercially available hydrophones utilize MEMS technology, so the team set out to understand whether such a design was possible.

With funding from the Office of the Under Secretary of War for Research and Engineering to develop a novel hydrophone, the team first planned to use microfabrication, an area of expertise at the laboratory, to develop their device. However, that approach proved to be too costly and involved to pursue. This obstacle led the team to pivot and build their hydrophone around a commercially available MEMS microphone. "We had to come up with an inexpensive alternative without giving up performance, and this is what led us to build the design around a microphone, which to our knowledge is a novel approach," Freeman explains.

In collaboration with researchers at Tufts University, as well as industry partners SeaLandAire Technologies and Navmar Applied Sciences Corp., the team made the hydrophone by encapsulating the MEMS microphone in a polymer with low permeability to water while leaving an air cavity around the microphone’s diaphragm (the component of the microphone that vibrates in response to sound waves). One key challenge that they faced was the possibility of losing too much signal to the packaging and the air cavity around the MEMS microphone. After a substantial amount of simulation, design iterations, and testing, the team found that the signal lost from incorporating air into the device was compensated for by the very high sensitivity of the MEMS microphone itself. As a result, the device was able to perform at a sensitivity comparable to high-end hydrophones at depths down to 400 feet and temperatures as low as 40 degrees Fahrenheit. To date, the collaborative effort has involved computational modeling, system electronics design and fabrication, prototype unit manufacturing, and calibrator and pool testing.

In July, eight researchers traveled to Seneca Lake in New York to test a variety of devices. The hydrophones were lowered to increasing depths in the water — 100 feet at first, then incrementally lower down to 400 feet. At each depth, acoustic signals of varying frequencies were transmitted for the instrument to record. The transmitted signals were calibrated to a known level so they could then measure the actual sensitivity of the hydrophones across different frequencies. When the sound hits the hydrophone’s diaphragm, it generates an electrical signal that is amplified, digitized, and transmitted to a recording device at the surface for post-test data analysis. The team utilized both commercial underwater cables as well as Lincoln Laboratory’s fiber-based sensing arrays.

"This was our first field test in deep water, and therefore it was an important milestone in demonstrating the ability to operate in a realistic environment, rather than the water chambers that we’d been using," Freeman says. "Our hope was that the performance of our device would match what we've seen in our water tank, where we tested at high hydrostatic pressure across a range of frequencies. In other words, we hoped this test would provide results that confirm our predictions based on lab-based testing."

The test results were excellent, showing that the sensitivity and the signal-to-noise was within a few decibels of the quietest ocean state, known as sea state zero. Moreover, this performance was achieved in deep water, at 400 feet, and with very low temperatures, around 40 degrees Fahrenheit.

The prototype hydrophone has applications across a wide variety of commercial and military use-cases owing to its small size, efficient power draw, and low cost.

"We're in discussion with the Department of War about transitioning this technology to the U.S. government and industry," says Freeman. "There is still some room for optimizing the design, but we think we've demonstrated that this hydrophone has the key benefits of being robust, high performance, and very low cost."

At first glimpse, student Jack Carson might appear too busy to think beyond his next problem set, much less tackle major works of philosophy. The sophomore, who plans to double major in electrical engineering with computing and mathematics, has been both an officer in Impact@MIT and a Social and Ethical Responsibility in Computing (SERC) Fellow in the MIT Schwarzman College of Computer Science — and is an active member of Concourse. 

But this fall, Carson was awarded first place in the Elie Wiesel Prize in Ethics Essay Contest for his entry, “We Know Only Men: Reading Emmanuel Levinas On The Rez,” a comparative exploration of Jewish and Cherokee ethical thought. The deeply researched essay links Carson’s hometown in Adair County, Oklahoma, to the village of Le Chambon sur Lignon, France, and attempts to answer the question: “What is to be done after catastrophe?” Carson explains in this interview.

Q: The prompt for your entry in the Elie Wiesel Prize in Ethics Essay Contest was: “What challenges awaken your conscience? Is it the conflicts in American society? An international crisis? Maybe a difficult choice you currently face or a hard decision you had to make?” How did you land on the topic you’d write about?

A: It was really an insight that just came to me as I struggled with reading Levinas, who is notoriously challenging. The Talmud is a tradition very far from my own, but, as I read Levinas’ lectures on the Talmud, I realized that his project is one that I can relate to: preserving a culture that has been completely displaced, where not destroyed. The more I read of Levinas’ work the more I realized that his philosophy of radical alterity — that you must act when confronted with another person who you can never really comprehend — arose naturally from his efforts to show how to preserve Jewish cultural continuity. In the same if less articulated way, the life I’ve witnessed in Eastern Oklahoma has led people to “act first, think later” — to use a Levinasian term. So it struck me that similar situations of displaced cultures had led to a similar ethical approach. Given that Levinas was writing about Jewish life in Eastern Europe and I was immersed in a heavily Native American culture, the congruence of the two ethical approaches seemed surprising. I thought, perhaps rightly, that it showed something essentially human that could be abstracted away from the very different cultural settings.

Q: Your entry for the contest is a meditation on the ethical similarities between ga-du-gi, the Cherokee concept of communal effort toward the betterment of all; the actions of the Huguenot inhabitants of the French village of Le Chambon sur Lignon (who protected thousands of Jewish refugees during Nazi occupation); and the Jewish philosopher Emmanuel Levinas’ interpretation of the Talmud, which essentially posits that action must come first in an ethical framework, not second. Did you find your own personal philosophy changing as a result of engaging with these ideas — or, perhaps more appropriately — have you noticed your everyday actions changing? 

A: Yes, definitely my personal philosophy has been affected by thinking through Levinas’ demanding approach. Like a lot of people, I sit around thinking through what ethical approach I prefer. Should I be a utilitarian? A virtue theorist? A Kantian? Something else? Levinas had no time for this. He urged acting, not thinking, when confronted with human need. I wrote about the resistance movement of Le Chambon because those brave citizens also just acted without thinking — in a very Levinasian way. That seems a strange thing to valorize, as we are often taught to think before you act, and this is probably good advice! But sometimes you can think your way right out of helping people in need. 

Levinas instructed that you should act in the face of the overwhelming need of what he would call the “Other.” That’s a rather intimidating term, but I read it as meaning just “other people.” The Le Chambon villagers, who protected Jews fleeing the Nazis, and the Cherokees lived this, acting in an almost pre-theoretical way in helping people in need that is really quite beautiful. And for Levinas, I’d note that the problematic word is “because.” And I wrote about how “because” is indeed a thin reed that the murderers will always break. 

Put a little differently, “because” suggests that you have to have “reasons” that complete the phrase and make it coherent. This might seem almost a matter of logic. But Levinas says no. Because the genocide starts when the reasons are attacked. For example, you might believe we should help some persecuted group “because” they are really just like you and me. And that’s true, of course. But Levinas knows that the killers always start by dehumanizing their targets, so they convince you that the victims are not really like you at all, but are more like “vermin” or “insects.” So the “because” condition fails, and that’s when the murdering starts. So you should just act and then think, says Levinas, and this immunizes you from that rhetorical poison. It’s a counterintuitive idea, but powerful when you really think about it.

Q: You open with a particularly striking question: What is to be done after catastrophe? Do you feel more sure of your answer, now that you’ve deeply considered these disparate response to a catastrophic event — or do you have more questions? 

A: I am still not sure what to do after world-historical catastrophes like genocides. I guess I’d say there is nothing to do — other than maintain a kind of radical hope that has no basis in evidence. “Catastrophes” like those I write about — the Holocaust, the Trail of Tears — are more than just acts of physical destruction. They destroy whole ways of being and uproot whole systems of meaning-making. Cultural concepts become void overnight, as their preconditions are destroyed. 

There is a great book by Jonathan Lear called “Radical Hope.” It begins with a discussion of a Plains Indian leader named Plenty Coups. After removal to the reservation in the 19th century, he is quoted as saying, “But when the buffalo went away the hearts of my people fell to the ground, and they could not lift them up again. After this nothing happened.” Lear ponders what that last sentence is all about. What did Plenty Coups mean when he said “after this nothing happened?” Obviously, life’s daily activities still happened: births, deaths, eating, drinking, and such. So what does it mean? It’s perplexing. In the end, Lear concludes that Plenty Coups was making an ontological statement, in which he meant that all of the things that gave life meaning — all of those things that make the word “happen” actually signify something — had been erased. Events occurred, but didn’t “happen” because they fell into a world that to Plenty Coups lacked any sense at all. And Plenty Coups was not wrong about this; for him and his people, the world lost intelligibility. Nonetheless, Plenty Coups continued to lead his people, even amidst great deprivation, even though he never found a new basis for belief. He only had “radical hope” — which gave Lears’ book its name — that some new way of life might arise over time. I guess my answer to “what happens after catastrophe?” is just, well, “nothing happens” in the sense Plenty Coups meant it. And “radical hope” is all you get, if anything.

Q: There’s a memorable scene in your essay in which, during a visit to your community cemetery near Stilwell, your grandfather points out the burial plots that hold both your ancestors, and that will eventually hold him and you. You describe this moment beautifully as a comforting and connective chain linking you to both past and future communities. How does being part of that chain shape your life? 

A: I feel this sense of knowing where you will be buried — alongside all of your ancestors — is a great gift. That sounds a little odd, but it gives a rootedness that is very removed from most people’s experience today. And the cemetery is just a stand-in for a whole cultural structure that gives me a sense of role and responsibility. The lack of these, I think, creates a real sense of alienation, and this alienation is the condition of our age. So I feel lucky to have a strong sense of place and a place that will always be home. Lincoln talked about the “mystic chords of memory.” I feel this very mystical attachment to Oklahoma. The idea that this road or this community is one where every member of your family for generations has lived — or even if they moved away, always considered “home” — is very powerful. It always gives an answer to “Who are you?” That’s a hard question, but I can always say, “We are from Adair County,” and this is a sufficient answer. And back home, people would instantly nod their heads at the adequacy of this response. As I said, it’s a little mystical, but maybe that’s a strength, not a weakness.

Q: People might be surprised to learn that the winner of an essay contest focusing on ethics is actually not an English or philosophy major, but is instead in EECS. What areas and current issues in the field do you find interesting from an ethical perspective?

A: I think the pace of technological change — and society’s struggle to keep up — shows you how important philosophy, literature, history, and the liberal arts really are. Whether it’s algorithmic bias affecting real lives, or questions about what values we encode in AI systems, these aren’t just technical problems, but fundamentally about who we are and what we owe each other. It is true that I’m majoring in 6-5 [electrical engineering with computing] and 18 [mathematics], and of course these disciplines are extraordinarily important. But the humanities are something very important to me, as they do answer fundamental questions about who we are, what we owe to others, why people act this way or that, and how we should think through social issues. I despair when I hear brilliant engineers say they read nothing longer than a blog post. If anything, the humanities should be more important overall at MIT. 

When I was younger, I just happened across a discussion of CP Snow’s famous essay on the “Two Cultures.” In it, he talks about his scientist friends who had never read Shakespeare, and his literary friends who couldn’t explain thermodynamics. In a modest way, I’ve always thought that I’d like my education to be one that allowed me to participate in the two cultures. The essay on Levinas is my attempt to pursue this type of education.

Hours before his resignation became public Monday, David Richardson told POLITICO's E&E News that "I have no idea what you're talking about."

The next three in this series on online events highlighting interesting uses of AI in cybersecurity are online: #4, #5, and #6. Well worth watching.

World leaders have vowed to fight rising temperatures for years. Many of those pledges fade when the summits end.

The incoming South Carolina facility will help First Solar build its unusual kind of solar panels, which utilize thin-film technology.

The Pennsylvania governor's deal to trade climate regulations for a budget agreement could ripple far beyond his state's borders.