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    How our SN 10 scientists have responded to tumultuous times

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    Each year since 2015, Science News has featured the work of outstanding early- and mid-career scientists in our SN 10: Scientists to Watch list. They’re nominated by Nobel laureates and members of the National Academy of Sciences, and are recognized because of their curiosity, passion, determination and, of course, their discoveries.

    But we decided that 2021 begs for something different. The coronavirus pandemic continues to rage worldwide, with its burdens falling hardest on those least able to bear them — inequities already on our minds due to Black Lives Matter, #MeToo and other social movements. At the same time, we’re learning that the window to reverse some of climate change’s most devastating effects is closing fast. With all the upheaval, we wondered: How do these extraordinary times change a scientist’s work?

    Here, we catch up with 10 noteworthy Scientists to Watch alumni. Emily Fischer, who studies wildfire smoke, has faced the threat of fires firsthand, cognitive neuroscientist Jessica Cantlon is fighting sexual harassment in the sciences and economist Parag Pathak is taking his efforts to make institutions more equitable from schools to hospitals. Other scientists reveal how their work has gained new urgency and meaning for them. The interviews that follow have been edited for length and clarity.

    — Elizabeth Quill

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    Scientists to Watch alumni

    Speaking out for women in science

    CARNEGIE MELLON UNIV.

    Jessica Cantlon

    Cognitive neuroscientistCarnegie Mellon University

    Jessica Cantlon, featured in 2016, studies the evolution and development of complex mathematical thinking, including the traits that set humans apart from other primates. In 2017, she was recognized as a Time Person of the Year, as a “silence breaker” speaking out against sexual harassment during the height of the #MeToo movement.

    What has been the most notable progress in your research since 2016?

    We’ve expanded our repertoire to compare people across different cultures, who have different educational practices. We’ve been going to Bolivia to work with this group of people called the Tsimane, who live in rural parts of the Amazon forest. They don’t have the rigid, formal schooling where kids go through these particular curricula to achieve mathematical cognition. Instead, education there is more organic and more deeply connected to their way of life. That allows us to try to understand what effect does a particular type of education have on numerical thinking.

    There was one study that we did, comparing species — nonhuman primates and humans — to understand the evolution of these concepts. Across all species and stages of development and cultural groups, there’s this bias that when you’re looking at a set of objects, and you’re trying to quantify it, you think about that set numerically. And you don’t have to; you can think about that set of objects spatially, as an amount of stuff, you can think about how much surface area is there, or the perimeter around it. But primates, including humans, [tend to] think about that set as a set of discrete objects, and count them up.

    What is something that excites you right now in your work?

    We’ve looked at the similarities and differences between boys and girls as their brains develop. We’ve done some of the first, early studies comparing children’s brains that can truly allow us to collect evidence on the trajectory of similarity between boys and girls…. We’ve shown that very early in development, between around 3 and 8 years of age, there’s evidence during mathematical processing that most of the brain — over 95 percent — shows functional similarity in that processing between boys and girls.

    But as we know, much later on in development, we see a severe underrepresentation of girls in mathematics-related fields. What’s happening? There’s evidence in the field … that what happens in late childhood and adolescence is that children’s interests are shaped culturally.

    What are some of the greatest challenges you’ve faced since 2016?

    In 2016, [some of my colleagues at the University of Rochester and I] filed a sexual harassment complaint against a faculty member in our department who was sexually harassing women — undergraduate and graduate students and faculty. It became this situation that hijacked my career for a number of years.… We went public with our complaint, partly to protect ourselves, but also partly to let people know at other universities that this kind of thing is happening to students, and it’s affecting women’s career paths in ways that are discriminatory and unequal.

    Ultimately, it was really important. Our complaint went public in September of 2017. In October 2017, the Harvey Weinstein story came out in the New York Times, and that kicked off a series of reactions that ultimately culminated in millions of people saying #MeToo, which I think was really powerful and important, and was something that we got to be a part of.

    I’ve had dozens of women reach out to me for advice, about how to file a complaint at their university, how to take legal action, if that’s what they’re thinking, what the risks and benefits are. And so, part of my career now — and I’m excited by it, and I think it’s really important work — is to be an advocate for women who are experiencing discrimination and harassment at universities.

    One response that we thought was really great was that the National Academies of Sciences, Engineering and Medicine did a full study on sexual harassment in the sciences…. It has a lot of ideas about what might effect larger-scale change.

    — Interview by Aina Abell

    From fair schools to vaccine distribution

    L. BARRY HETHERINGTON

    Parag Pathak

    EconomistMIT

    Parag Pathak, featured in 2019, strives to make public education more equitable. He has used data and algorithms to overhaul school choice systems in Boston, New York and other U.S. cities. Now he’s applying his research to the question of how to equitably distribute vaccines and other medical resources.

    What’s the most notable progress in your work since 2019?

    Since we last talked, I released a paper on the effects of universal preschool. A lot of people are interested right now because [universal preschool, which is open to everyone with no income rule,] is part of the White House’s agenda. Because of the work we had done with Boston with their school choice algorithm over the years, we had some files on school admissions going back to the late 1990s. Boston was a leader nationwide in expanding slots for children in preschool. But, like many cities, there weren’t enough slots for demand, so they had to ration. And that’s where the lotteries come in.

    Fast forward to now. We linked these applicant cohorts to standardized test scores and educational outcomes all the way into college. And what we found was pretty exciting: Those who won the [preschool] lottery are more likely to graduate high school, they score higher on SATs and they’re more likely to enroll in college. Boston has continued to refine and try to improve [the lottery system]. It’s a model for other cities that are expanding public preschool.

    Are you pursuing any new questions or projects?

    COVID-19 was this huge shock. We all were looking around for how we could be useful, using our respective toolboxes. Tayfun Sönmez, M. Utku Ünver and M. Bumin Yenmez, all of Boston College — the four of us — started to study how scarce medical resources are rationed. And it turns out, there are some parallels with the way school seats are rationed.

    One of the ideas that we’ve explored is the idea of a reserve system. In cases where people can’t agree on what’s fair, who should get a vaccine first? It’s very similar to who should get into a school. And the way that [schools] have handled that is they set up more elaborate versions of priority systems. With a vaccine reserve system, you basically have a [supply] that’s reserved for cardiac communities, and one that’s reserved for frontline medical personnel, so on and so forth…. States like California and Massachusetts have used some of our ideas [for their reserve systems].

    My wife [Ruma Rajbhandari] is a medical doctor, and my sister [Sapana Adhikari] is an emergency room physician. A big part of my interest in medical rationing guidelines was their having to go to the hospital in March 2020 not knowing what the risks were and not having personal protective equipment. That was something that got me really keen on this debate about frontline health care workers, do they get first priority or not?

    How has the pandemic shifted how you view your work in the area of education?

    I have a kindergartner who was virtual this past year. And he did an amazing job with it. I think what the pandemic has done is rip the Band-Aid off on these lingering problems in society — inequitable access to health care, inequitable access to education, inefficiencies in both of the systems — and has made them much more pronounced. That’s been the theme of our research throughout. We hope more people take these issues on, because the way COVID-19 played out was really a scarring event in terms of haves and the have-nots.

    — Interview by Cassie Martin

    How social stressors mark our genes

    MEGAN MENDENHALL/DUKE UNIV.

    Jenny Tung

    Evolutionary anthropologistDuke University

    Jenny Tung, featured in 2018, studies how social environments — including social status, relationships and isolation — influence primates’ genes and health. Her study subjects have included captive rhesus macaques and wild baboons.

    What has been the most notable progress in your work since 2018?

    We have built layers of complexity onto [our] initial story. A few years ago we were showing that it’s possible for social interactions to have profound effects on the function of our genome. And now we’re trying to derive a much better understanding of how and why and when, and what are the exceptions.

    The other thing I’m really excited about is our ability to move away from this very powerful but very artificial system using captive primates and to ask about what’s going on in the field with wild monkeys. I’ve studied wild baboons in Kenya for many, many years. We know a lot about the social environments, the social experiences. And now with the ability to collect some simple blood samples, we’re also seeing strong signatures of things like social status and social integration, social bonds, social connectedness in the function of these animals’ genomes. That’s pretty exciting because lab studies are powerful and wonderful, but there’s always this question of, “Well, is this real in the real world?”

    You were named a MacArthur Fellow in 2019. What have you been pursuing since?

    It was a real honor. It has encouraged us to continue down some of these paths … and to also do some more comparative work and think about species beyond the ones that I have traditionally studied. So in the past few years, I’ve picked up work in other social mammals — wild meerkats and these very social rodents called mole rats — that have their own advantages in giving us insight into how our social world has shaped both how we came to be, our evolutionary past, and how we do day to day in our present.

    I’ve been doing more work on something that’s an old love of mine: trying to understand the evolutionary consequences of intermixing between different primates. The population of baboons that I study in Kenya actually sits right at the edge of where the ranges of two different species of baboons meet. And so this population is intermixed between one species, the Anubis baboon, and this other species, the yellow baboon.… We think those patterns of intermixture influence some things about what [the animals] look like, how they behave and so on.…

    We know that [humans] have also intermixed a lot with some groups that don’t even exist today, like Neandertals and Denisovans. That process of admixture that we observe right now in living primates [is] potentially relevant to understanding our species’s history.

    What are some of the greatest challenges you’ve faced since 2018?

    In many ways, I felt very fortunate during the pandemic; as an academic with tenure, I have a secure job. But we were also home with a 3-year-old for a long stretch. I spend usually at least a month a year in Kenya, and I have since 2006. But not in 2020. We had to figure out some way of keeping [the research] continuous without any ability to travel there. We have a permanent staff in Kenya — they are Kenyan — who are very important to us and have been working with our project in some cases for many decades, and they were having their own issues, and isolation, and risks in the face of a lot of uncertainty.

    I spend a lot of time in my research life thinking about social interactions. And every species that I study … they live in groups. And humans, to a large extent, we live together. We didn’t evolve to be on our own for a long period of time. And so I spent a lot of time reading and thinking and working on, “Why when you don’t have the right sort of social connections, why does your risk of death just shoot up? What’s the consequence of chronic social stress?” One of the things that I really appreciate in a more visceral manner [now] is how important my social network is to me. I think that we’re all looking for ways to connect during the pandemic. And that’s when your personal experience and the things that you’re writing papers about and thinking about really collide.

    — Interview by Aina Abell

    Breaking the one test for one cancer paradigm

    COURTESY OF THRIVE

    Isaac Kinde

    Molecular biologistThrive Early Detection

    Isaac Kinde, featured in 2015, is developing tests to detect cancer early, when treatment is more likely to be successful. In 2019, PapGene, a small biotech start-up where he was chief scientific officer, was acquired by Thrive, cofounded by Kinde. Just this year, it got the backing of the much larger cancer diagnostics firm Exact Sciences.

    Could you tell us about Thrive and what spurred this transition?

    Thrive basically acquired the predecessor company [PapGene]…. There was a lot more money, there’s a lot more expertise, but the core mission didn’t change, which is to develop cancer diagnostic products that we think will have an impact on the lives of people with cancer. We have essentially turbocharged and focused our efforts, leading with the most promising product, which is CancerSEEK.

    The premise is we can reduce cancer morbidity and mortality through earlier detection. CancerSEEK is a blood test, and it is a multi-cancer test. That contrasts with the current paradigm, which is one test, one cancer.… Right now, all of our efforts are on making it commercially available.

    CancerSEEK, which is still in testing, picks up on DNA mutations and proteins associated with cancer. How many cancers can it detect at this time?

    There’s good evidence for detecting over 60 to 70 percent of the cancers that cause the most deaths per year. That boils down to … colon, breast, lung…. But the [full] range is bigger than those three. There’s esophageal, gastric, kidney, pancreatic. There’s data that support maybe 12 to 13 different cancers.

    You published what you’ve referred to as a “landmark study” in Science last year. What did it find?

    We call it a landmark study because it was the first demonstration in a prospective setting of how a multicancer blood test could be used in real time to report results to patients with cancer.

    We looked at 10,000 women in the Geisinger Health system. It’s primarily women who are in Pennsylvania…. In the study, 24 [women had cancers] detected with standard-of-care screening: colonoscopy, mammography or low-dose CT scan for lung. Then there were 26 cancers in which the CancerSEEK test detected the cancer first…. Sixty-five percent of the cancers we detected were at a stage prior to stage 4. So [the addition of CancerSEEK] doubled the number of cases that were [found before symptoms were reported] — in many, many cases early enough where some effective therapies could be implemented.

    And then it was also safe…. There were very few false positives, and we could very quickly resolve the false positives with whole-body PET-CT imaging. At least two patients [who first had detections from CancerSEEK] had their cancers successfully removed and are thriving as of the last time we checked.

    Routine cancer screenings fell during the pandemic. Has this affected your work?

    It fans the flame, right? The reason why cancer screening went down is not because there was less cancer. It was [just] more difficult for whatever reason to get the appropriate standard-of-care test.… All this did was just strengthen the case that more tools, easier tools are needed for cancer screening. And I think maybe the other feeling is just wishing we could go even faster, but balancing a commercial launch with having all the right pieces in place that will set us up for success.

    — Interview by Ashley Braun

    Pig organs for people move closer to reality

    QIHAN BIOTECH

    Luhan Yang

    BiologistQihan Biotech

    When featured in 2017, Luhan Yang had cofounded and was chief scientific officer of eGenesis, a biotech start-up. She is now cofounder and CEO of Qihan Biotech, based in Hangzhou, China, which aims to develop animal organs that are safe for human transplant and to make cell therapies that can treat conditions such as cancer and autoimmune diseases more widely accessible.

    What is some of the most notable progress in your work since 2017?

    The concept of xenotransplantation is to use animal organs as an alternative resource for human transplantation, since there is a huge unmet need for organs. There are two fundamental issues to be addressed. One is [that] there are endogenous retroviruses in the pig genome — some virus sequences — and they can jump around within the pig genome. The viruses can also jump from the pig cell to the human cell. So there is a potential cross-species transmission, which is a huge safety and regulatory concern.… The second hurdle of using pig organs for human transplant, as you can imagine, is rejection, and it is tremendous.

    Those are the two fundamental problems … and that’s where we think gene editing can come into play. By 2017, our team had knocked out 62 [retrovirus copies]. Since then, there are three notable milestones: First, we have created our Pig 2.0, with 15 modifications for immunology…. Last year in Nature Biomedical Engineering, we showed that those modifications are properly expressed in the pig cell, and the resulting pig is healthy, as well as fertile, and the genetic modification can be passed to the offspring. The second part is we combined the [retrovirus] knockout and the immune rejection–related modification in a single pig. We call it Pig 3.0. So that is a prototype close to clinical trial.

    The third part is the most exciting part for us: We need to test the function. [In a recent study published in the American Journal of Transplantation,] we put the pig kidney into a monkey. If it’s a normal pig kidney, it will be rejected in a few minutes. And right now the longest survival of our monkey is about one year.… The monkey experiment demonstrates the possibility of achieving long-term xenotransplantation.

    What was it like to move from the lab to leading a company?

    Being a leader in biotech is not all business. There are three components that are needed. The first part is to set the vision and strategy of the company. In such an innovative area, I think the scientific knowledge, the breadth of the exposure, I think that’s my strength.… The second part is to recruit, retain and train people. And the last part is some business judgment, like how to do fund-raising, how to organize a project, the accounting. I have to admit, I’m not the expert. But I think at my position, the key is to recruit the best people to do the job.… And I started to embrace that every leader has different strengths and weaknesses.

    How has the pandemic influenced your company’s international collaborations?

    I was hoping we could have more in-person meetings or travels, but right now, China still has the quarantine policy that makes it super inconvenient for international travel. Hopefully with the vaccine, the world will become what it was.

    I feel the world is more divided compared with 10 years before. And I hope at least for medicine, we can see that our enemy is not a different country, but our enemy is cancer, is organ failure, is COVID, that we can keep and strengthen the collaboration across borders.

    — Interview by Aina Abell

    Seeking solutions to climate change

    AMY PERL PHOTOGRAPHY

    Jeremy Freeman

    Scientist and designerCarbonPlan

    When he was featured in 2016, Jeremy Freeman was developing new tools and methods to help scientists better analyze brain data. Now he is executive director of CarbonPlan, a nonprofit organization that he founded in March 2020 to tackle the climate crisis through open-source data and research.

    You’ve shifted gears since 2016. Tell us about it.

    I moved very far from neuroscience, and I’m now exclusively working on climate change. Our focus [at CarbonPlan] is the scientific integrity and transparency of climate solutions. [We do] a combination of research on different areas of climate science and strategies for addressing climate change. We [also] produce a variety of resources and tools for both the research community and the public at large.

    Despite being a radically different field, there are some interesting commonalities, in terms of the value of having very accessible, open, publicly available data that speaks to critical issues. [For climate change,] issues around both what is changing in the climate and how we might address that, in different strategies we might take. Having as much of that information be developed in the open, in a way that others can contribute to, and making work available for others to read and evaluate and criticize and engage with — those are [also] values I felt really strongly about in the world of biomedical science.

    What CarbonPlan work are you most proud of right now?

    We have done a lot of analysis identifying very specific ways in which the implementation of forest carbon offset programs [the planting or preservation of trees to attempt to compensate for carbon emissions] haven’t worked. We did a comprehensive analysis of the role of forest carbon offsets in California’s cap-and-trade program, which is a massive sort of market of offsets on the order of $2 billion, and we identified about $400 million worth of offset credits that in our analysis do not reflect real climate benefits because of errors in how they were calculated with respect to issues that involve fundamental problems in statistics and ecology.

    That team effort, led by Grayson Badgley and Danny Cullenward, along with a lot of other work that we’ve done on the role of offsets, is really starting to change the conversation, and wake people up to the fact that these approaches to dealing with climate change haven’t been working.

    What other questions are you looking at?

    There’s an area known as carbon removal, which refers to any mechanisms that draw down CO2 from the atmosphere. And carbon removal is really, really complicated, because there are a lot of different ways to potentially accomplish that.… So that’s an area where we’ve been very involved, studying, analyzing, comparing. We helped write, edit and produce a book called the CDR Primer — carbon dioxide removal primer. It’s, of course, a publicly available resource.

    Have recent social justice movements influenced your work?

    Absolutely.… Climate change is so fundamentally an issue of equity and an issue of justice. The burdens of climate change are going to be borne by those who were not directly responsible for it, and those who in many ways have been responsible for it will be more able to avoid its impacts. And there’s a deep injustice in that.… How to think about that is an important aspect of our work.… We’re interested in finding a way to be really complementary to a lot of existing community efforts around these issues.

    — Interview by Aina Abell

    Astrophysicist writes about the stars for Spanish speakers

    MARIANA SOLEDAD

    Paula Jofré

    AstrophysicistUniversidad Diego Portales

    Paula Jofré, featured in 2018, used the chemical composition of stars across the Milky Way like DNA to map the stars’ family tree. She recently filled in some details of the tree — and is filling a gap in the publishing world by writing a book about stars in Spanish.

    What progress have you made on your stellar family tree?

    In the first paper, the tree had three main branches. There was one that we could associate with a young thin disk, which is one of the populations in the Milky Way. Another was associated with an old, thick disk, which was the older component of the Milky Way. And then we had something in between…. Now, because we had more stars and more chemical elements and we made a better selection of which chemical elements to include, we could find that this strange population was actually an ancestor population of the thin disk. And one of the interpretations we had in the second paper [published in January in the Monthly Notices of the Royal Astronomical Society] was that they were produced all very quickly.

    Other groups have found striking evidence of a galaxy that was merged into the Milky Way [billions of years ago]. And that [merging and mixing of gas] could have triggered what is called a star formation burst — lots of stars [forming] at the same time. So, it’s kind of exciting that we find in the tree a feature that could be attributed to a star formation burst … a few gigayears after the [merger of these two galaxies] that we know happened.

    You’re also writing a popular book on stars. Can you tell me more about the book, Fósiles del cosmos: descifrando la historia de la Vía Láctea, or Fossils of the Cosmos: Deciphering the History of the Milky Way, and why you decided to write it?

    It’s going to be published in November [in Chile]. It’s a book in Spanish for the public. I am teaching a class about stars in the Milky Way, a general astronomy class. And I’ve been finding that there is no proper literature in Spanish for the students.… The level is sometimes way too basic or too complex. So I wanted to write something for their level.

    [The book] explains how stars create the chemical elements, what’s the role of Gaia [a satellite mission to map the galaxy], what’s the role of the Milky Way Mapper [another survey using Earth-based telescopes], about all these big surveys, why we care, what’s going on.

    When I started writing it, of course, I started reading other books…. In all these general astronomy books, women are never highlighted. In my book, I have lots of quotes from 40 different women all around the world, working in my field.… I want to make the point that you can be a woman, you can be clever, you can dedicate yourself to something that is mentally challenging. You can be like any of these 40 women.

    What’s the greatest challenge that you’ve faced since 2018?

    The biggest challenge has been to promote hiring more women at the faculty level. Chile’s a very small country and they love new figures, young figures being highlighted by the United States. The moment I was in Science News,I became very popular [in Chile] very quickly. They needed the inspirational woman. And I kept saying, “I don’t want to be the only one. I want more women.”

    I don’t know if you were aware of this collective Las Tesis; they made a dance for the social unrest that we had in Chile before the pandemic. It was a feminist movement that resonated for so many people in the world. The movement [says]: We want to be treated with respect, we want the same salary, we want the same opportunities, we want to feel safe on the streets.… But then, when you are fewer in academia, you’re not going to start jumping on the table and dancing, right? You have to argue … it’s difficult.

    — Interview by Ashley Braun

    A clever genetic tool tackles new troubles

    S. QI

    Stanley Qi

    BioengineerStanford University

    By disabling the DNA-cutting enzyme in the CRISPR system, Stanley Qi, featured in 2019, created a new and versatile tool. Attaching a range of molecules to these “dead Cas” enzymes has yielded an entire toolbox worth of DNA and RNA manipulators.

    Is the strategy of disabling Cas molecules still popular among researchers?

    I feel it’s getting more popular, for a number of reasons: One, people use … this tool to study how the genome works. Two, there are some new efforts using the tool to treat some genetic diseases. And three, there are some other exciting uses of this tool to think about other diseases, other topics that we can possibly tackle.

    For example, this CRISPR system came from bacteria cells, right? They were used as weapons by the bacteria to fight against invading viruses. So we said, “OK, humans also have many foes like invading viruses. Can we repurpose this CRISPR to help us fight our infectious diseases?” That was the idea before the COVID-19 pandemic. We practiced first on influenza, seasonal flu…. We adapted a type of CRISPR system that targets a specific RNA molecule, and it works pretty well. I remember it working in January [2020] when the news started reporting, “Oh, there’s a new virus, it’s an RNA virus,” and we thought immediately, “What if we use this tool on this new RNA virus?”

    Instead [of using the live virus], we used synthetic biology to mimic the RNA sequence.… [And we found] we can still very rapidly cleave and destroy this RNA virus and its fragments in the human lung cells. We were really excited. Since then we’ve been working very hard to follow up on the idea, to make this as fast as possible into a possible antiviral. We called it PAC-MAN.

    Can you talk a bit about how the dead Cas, or dCas, approach has been improved and adapted?

    One bigger use is for treating disease like a gene therapy. However, there’s still a number of features that have not been ideal for easy use or testing in clinics.… [For patient care,] people always think about making the system very, very compact and suitable into a nanoparticle or into a viral particle, so we can deliver them with ease into the human body. So that requires a miniaturization of the CRISPR system. And we actually did some work on that…. They are like two-thirds smaller than what people use.

    And second is, many of these natural proteins from bacteria don’t work very well [in human cells].… So we did some protein engineering. Following these efforts, we actually created some highly compact, yet highly efficient dCas systems that can be easily delivered into the human body to turn on or off genes.

    What are the greatest challenges you’ve faced in the last couple of years?

    We are bioengineers and we think our strength is in creating stuff, modifying. Now as we step into the domain of applying these tools to solve real-world problems, the challenge is how to build a bridge between where we are to where we want to go. That usually requires learning a significant amount about a disease, about a new field, and thinking creatively on how to interface two fields.

    — Interview by Ashley Braun

    Research on wildfire smoke hits close to home

    BILL COTTON, COLORADO STATE UNIV. PHOTOGRAPHY

    Emily Fischer

    Atmospheric chemistColorado State University

    Emily Fischer, featured in 2020, is in the midst of one of the most comprehensive analyses of wildfire smoke ever attempted. Since we last chatted with Fischer, her wildfire research and the way she talks about it have become more personal.

    Have you started any projects since 2020?

    We’re looking at the impact of smoke on the visible light range where photosynthesis occurs. There’s smoke blanketing the U.S. in summers now. Regardless of whether it’s at the ground, it’s somewhere in the atmosphere between the sun and the plants on the ground. In the Midwest, for example, over our corn and soybean belt, there’s smoke between a third to half of the days on average in July and August, during peak growing season. What does that mean for crops? How is that changing the light at the surface? If it’s boosting the diffuse fraction of radiation, and not decreasing the total radiation, that’s a boost to productivity.

    Last year, you helped launch a national group called Science Moms. What is that?

    We are a nonpartisan group of scientists who are also mothers. The goal of Science Moms is for us to speak directly [via a website, videos and events] on climate change to other mothers in ways that are accurate, digestible and also engaging. While roughly 60 percent of the U.S. population is worried about climate change, like 85 percent of moms are worried about climate change. But they don’t feel comfortable talking about it, or know how to talk to their representatives about it or even talk to their book club about it.

    How have people responded to your outreach efforts?

    I get all sorts of messages: “This is so different than any other climate communication that I’ve ever seen.” We’re trained as scientists to take the emotion out of things, but actually it’s very important for people to understand the feeling of climate change.

    Last summer [2020], extreme fires impacted my own home. We had smoke here for multiple months, and my family ran from the Cameron Peak Fire.… For me, there was a shift from “These are the numbers, these are the graphs,” to “Oh, this is what my graphs feel like, this is what this trend feels like.”

    Did your experience fleeing a wildfire shift your perspective around your science?

    I’m the kind of person who studies what I see.… And so I should not have been surprised by that fire. I was out backpacking with my family, and it started one range over and my kids and I ran out, and we made it. So it was OK, but I was not sure it would be OK. When something like that happens to you, you have to respond to it. [Now] I think, when we calculate a change in something going forward, what does that mean? What are all the impacts that that could have?

    Also, seeing the incident management teams working together to help people [during the fire] was very inspiring. I would say to my husband, “These teams are beautiful. They are functioning at such a high level under such hard conditions. If we could just harness this level of cooperation toward climate change action, or toward eliminating the pandemic, we [could] do anything.”

    — Interview by Cassie Martin

    The search for exomoons continues

    D. KIPPING

    David Kipping

    AstronomerColumbia University

    After being featured in 2017, David Kipping and his colleagues formally reported in Science Advances the first detection of a potential exomoon — a moon orbiting a planet outside of the solar system. Signs of the Neptune-sized moon were spotted around a Jupiter-sized planet 8,000 light-years from Earth. Kipping has been hunting for more ever since, and has also become a hit on YouTube.

    Have you found any more exomoons?

    Well, I can’t really talk about that. We are close to releasing the results of a new survey of the ensemble of Jupiter-like planets discovered by the Kepler space telescope. Such planets are thought to be the best hunting ground for moons, being far from the gravitational influence of their star and large enough to support potentially massive moons. Unfortunately, the results are still not quite ready.

    How have other scientists reacted?

    The community is naturally skeptical. That was kind of the story of exoplanets. When researchers first discovered a hot Jupiter, no one believed it. It wasn’t until they discovered about 10 of them that people started to say that, actually, maybe these are real. I don’t know how it’s going to go with any exomoon candidate. Maybe what we’ve found is genuinely bogus, but I obviously hope not. We did our due diligence, and we’re very careful with the results.

    It’s maybe not surprising that the first ones we find are going to be so large, because after all, they’re going to be the easiest to detect.… Actually, less than 1 percent of sunlike stars have hot Jupiters, but they dominated all of the first exoplanet detections just because they were so easy to find. Maybe the same thing will play out here.

    In 2017, you had just launched a YouTube channel called Cool Worlds. How is that outreach going?

    It’s been pretty overwhelming to us, because I’d never expected to get anywhere near the number of people watching who have watched. The last video [on what’s called the red sky paradox] got 200,000 views, and the one before it got 500,000. I mean, that’s just bonkers. I get e-mails from people, really amazing e-mails, that say how much the channel and the videos mean to them. That’s really incredible.

    We have lots of people actually financially supporting us now. We give them special access to the videos and early access to the papers we’re writing. We hang out with some of them once every two months on a livestream and chat about science. It’s starting to be enough that I’m funding students through donations. I have this dream that I do research, it produces cool ideas, I talk about it on my outreach channel, people get excited about it and they support us, which enables me to do more research.

    What are the greatest challenges you’ve faced since 2017?

    I’m still [working to earn] tenure. It’s obviously one of the most stressful periods of your career because you don’t have that safety net yet that some young tenured colleagues enjoy. At the same time, you’re trying to raise a family and make sure you see your kids growing up. You don’t want to be a ghost at home. And so that’s been tricky, but [the pandemic] enabled me to spend a lot more time at home with the family.

    — Interview by Cassie Martin More

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      Work on complex systems, including Earth’s climate, wins the physics Nobel Prize

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      Earth’s climate is a vastly complex system on a grand scale. On a microscopic level, so is the complicated physics of atoms and molecules found within materials. The 2021 Nobel Prize in physics knits together the work of three scientists who illuminated such intricate physical systems by harnessing basic tools of physics. 

      Half of the prize goes to climate scientists Syukuro Manabe of Princeton University and Klaus Hasselmann of the Max Planck Institute for Meteorology in Hamburg, Germany, for their work on simulations of Earth’s climate and predictions of global warming, the Royal Swedish Academy of Sciences announced October 5. The other half of the 10 million Swedish kronor (more than $1.1 million) prize goes to physicist Giorgio Parisi of Sapienza University of Rome, who worked on understanding the roiling fluctuations within disordered materials.

      All three researchers used a similar strategy of isolating a specific piece of a complex system in a model, a mathematical representation of something found in nature. By studying that model, and then integrating that understanding into more complicated descriptions, the researchers made progress on understanding otherwise perplexing systems, says physicist Brad Marston of Brown University. “There’s an art to constructing a model that is rich enough to give you interesting and perhaps surprising results, but simple enough that you can hope to understand it.”

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      The prize, normally an apolitical affair, sends a message to world leaders: “The notion of global warming is resting on solid science,” said Göran Hansson, secretary-general of the Royal Swedish Academy of Sciences, during the announcement of the prize winners. Human emissions of greenhouse gases, including carbon dioxide, have increased Earth’s average temperature by more than 1 degree Celsius since preindustrial times. That warming is affecting every region on Earth, exacerbating extreme weather events such as heat waves, wildfires and drought (SN: 8/9/21). 

      Syukuro Manabe of Princeton University (left) and Klaus Hasselmann of the Max Planck Institute for Meteorology (right) worked on early simulations of Earth’s climate, laying the foundation for today’s more detailed climate models that are used to grapple with the potential impacts of global warming.From left: Bengt Nyman/Wikimedia Commons (CC BY 2.0); Sueddeutsche Zeitung Photo/Alamy Stock Photo

      Manabe’s work laid the foundation for climate modeling, said John Wettlaufer of Yale University, a member of the Nobel Committee for Physics. “He really did construct the models from which all future climate models were built,” Wettlaufer explained during an interview after the prize announcement. “That scaffolding is essential for the improvement of predictions of climate.” 

      Manabe studied how rising carbon dioxide levels would change temperatures on Earth. A simplified climate model from a 1967 paper coauthored by Manabe simulated a single column of the atmosphere in which air masses rise and fall as they warm and cool, which revealed that doubling the amount of carbon dioxide in the atmosphere increased the temperature by over 2 degrees C. This understanding could then be integrated into more complex models that simulated the entire atmosphere or included the effects of the oceans, for example (SN: 5/30/70). 

      “I never imagined that this thing I would begin to study had such huge consequences,” Manabe said at a news conference at Princeton. “I was doing it just because of my curiosity.”

      Hasselmann studied the evolution of Earth’s climate while taking into account the variety of timescales over which different processes operate. The randomness of daily weather stands in contrast to seasonal variations and much slower processes like gradual heating of the Earth’s oceans. Hassleman’s work helped to show how the short-term jitter could be incorporated into models to understand the long-term change in climate. 

      Giorgio Parisi of Sapienza University of Rome is known for his work delving into the physics of disordered materials, such as spin glasses, in which different atoms can’t come to agreement about which direction to point their spins. Lorenza Parisi/Wikimedia Commons

      The prize is an affirmation of scientists’ understanding of climate, says Michael Moloney, CEO of the American Institute of Physics in College Park, Md. “The climate models which we depend on in order to understand the impact of the climate crisis are world-class science up there with all the other great discoveries that are recognized [by] Nobel Prizes of years past.”

      In a spin glass, illustrated here, iron atoms (red), within a lattice of copper atoms (blue), have spins (black arrows) that can’t agree on a direction to point.C. Chang

      Much like the weather patterns on Earth, the inner world of atoms within materials can be complex and disorderly. Parisi’s work took aim at understanding the processes within disordered systems such as a type of material called a spin glass (SN: 10/18/02). In spin glasses, atoms behave like small magnets, due to a quantum property called spin. But the atoms can’t agree on which direction to point their magnets, resulting in a disordered arrangement.

      That’s similar to more familiar types of glass — a material in which atoms don’t reach an orderly arrangement. Parisi came up with a mathematical description for such spin glasses. His work also touches on a variety of other complex topics, from turbulence to flocking patterns that describe the motions of animals such as starlings (SN: 7/31/14). 

      Although his work doesn’t directly focus on climate, in an interview during the Nobel announcement, Parisi commented on that half of the prize: “It’s clear that for the future generation we have to act now in a very fast way.” 

      Carolyn Gramling contributed to reporting this story. More

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      2020 babies may suffer up to seven times as many extreme heat waves as 1960s kids

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      The kids are not all right. Children born in 2020 could live through seven times as many extreme heat waves as people born in 1960.

      That’s the projected generational disparity if global greenhouse gas emissions are curbed by the amount currently promised by the world’s nations, climate scientist Wim Thiery of Vrije Universiteit Brussel in Belgium and colleagues report September 26 in Science. Under current pledges, Earth’s average temperature is expected to increase by about 2.4 degrees Celsius relative to preindustrial times by 2100. While the older generation will experience an average of about four extreme heat waves during their lifetime, the younger generation could experience an average of about 30 such heat waves, the researchers say.

      More stringent reductions that would limit warming to just 1.5 degrees C would shrink — but not erase — the disparity: Children born in 2020 could still experience four times as many extreme heat waves as people born in 1960.

      Scientists have previously outlined how climate change has already amped up extreme weather events around the globe, and how those climate impacts are projected to increase as the world continues to warm (SN: 8/9/21). The new study is the first to specifically quantify how much more exposed younger generations will be to those events.

      An average child born in 2020 also will experience two times as many wildfires, 2.8 times as many river floods, 2.6 times as many droughts and about three times as many crop failures as a child born 60 years earlier, under climate scenarios based on current pledges. That exposure to extreme events becomes even higher in certain parts of the world: In the Middle East, for example, 2020 children will see up to 10 times as many heat waves as the older cohort, the team found.

      With this possible grim future in mind, student climate activists in the #FridaysforFuture movement have been among the most powerful voices of protest in recent years (SN: 12/16/19). Thiery and colleagues note that these findings come at a crucial time, as world leaders prepare to gather in Glasgow, Scotland, in late October for the 2021 United Nations Climate Change Conference to negotiate new pledges to reduce greenhouse gas emissions. More

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      A volcano-induced rainy period made Earth’s climate dinosaur-friendly

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      The biggest beasts to walk the Earth had humble beginnings. The first dinosaurs were cat-sized, lurking in the shadows, just waiting for their moment. That moment came when four major pulses of volcanic activity changed the climate in a geologic blink of an eye, causing a 2-million-year-long rainy spell that coincided with dinos rising to dominance, a new study suggests.

      Clues found in sediments buried deep beneath an ancient lake basin in China link the volcanic eruptions with climate swings and environmental changes that created a globe-spanning hot and humid oasis in the middle of the hot and dry Triassic Period, researchers report in the Oct. 5 Proceedings of the National Academy of Sciences. During this geologically brief rainy period 234 million to 232 million years ago, called the Carnian Pluvial Episode, dinosaurs started evolving into the hulking and diverse creatures that would dominate the landscape for the next 166 million years.

      Previous research has noted the jump in global temperatures, humidity and rainfall during this time period, as well as a changeover in land and sea life. But these studies lacked detail on what caused these changes, says Jason Hilton, a paleobotanist at the University of Birmingham in England.

      So Hilton and his colleagues turned to a several-hundred-meter-long core of lake-bottom sediments drawn from the Jiyuan Basin for answers. The core contained four distinct layers of sediments that included volcanic ash that the team dated to between 234 million and 232 million years ago, matching the timing of the Carnian Pluvial Episode. Within those layers, the team also found mercury, a proxy for volcanic eruptions. “Mercury entered the lake from a mix of atmospheric pollution, volcanic ash and also being washed in from surrounding land that had elevated levels of mercury from volcanism,” Hilton says.

      The rock record from 234 million to 232 million years ago, captured in these cores from an ancient lakebed in northern China, shows signs of wet weather almost everywhere. The cores also show evidence of volcanic activity. Jing Lu

      Further evidence for the link between volcanism and environmental change during the Carnian Pluvial Episode came from corresponding layers in the core that showed different types of carbon, indicating four massive releases of carbon dioxide into the atmosphere. Finally, microfossils and pollens changed within the same core section, from species that prefer drier climates to ones that tend to grow in warm and humid climates.

      The reconstructed history suggests that the volcanic pulses injected huge amounts of CO₂ into the atmosphere, says coauthor Jacopo Dal Corso, a geologist at the University of Leeds in England. That boosted temperatures and intensified the hydrologic cycle, enhancing rainfall and increasing runoff into lakes, he says. At the same time, terrestrial plants evolved, with humidity-loving flora becoming predominant. As the rains created wet environments, turtles, large amphibians called metoposaurids — and dinosaurs — began to thrive.

      Together, these diverse lines of evidence reveal that the Carnian Pluvial Episode was actually four distinct pulses of significant environmental change — each triggered by massive volcanic eruptions, Dal Corso says.

      Pollens, spores and algae collected from the core sample from the Carnian Pluvial Episode reveal a change from more arid-loving plants and animals to more humid-loving plants and animals.Peixin Zhang

      The mercury and carbon data together suggest the increase in mercury came from a “major source of volcanism that was capable of impacting the global carbon cycle,” rather than local eruptions, the team writes. That volcanism likely came from the Wrangellia Large Igneous Province eruption in what is now British Columbia and Alaska, which has previously, but tenuously, been linked to the Carnian Pluvial Episode. If true, it means the Wrangellia eruption occurred in pulses, rather than one sustained eruption.  

      This paper marks the “first time that mercury and carbon isotope data are so well correlated across the Carnian Pluvial Episode,” says Andrea Marzoli, an igneous petrologist at the University of Padua in Italy who has studied Wrangellia but was not involved in this research.  “The authors make a strong argument in favor of volcanically induced global climate change pulses.” However, Marzoli notes, “the link to Wrangellia is still weak, simply because we don’t know the age of Wrangellia.”

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      Alastair Ruffell, a forensic geologist at Queen’s University Belfast in Ireland not involved in this study, agrees, saying he’d like to see more evidence of cause and effect between Wrangellia and the environmental changes. This study offers some of the best proxies and data from terrestrial sources to date, but more terrestrial records of the Carnian Pluvial Episode are needed, he says, to “understand what this actually looked like on the ground.” 

      The climate changes marked a tipping point for life that couldn’t adjust, and those groups went extinct. Animals like dinosaurs and plants like cycads, says Ruffell, were “waiting in the wings” to seize their opportunity. A similar cycle of volcanic activity and environmental change starting about 184 million years ago may have paved the way for the biggest of all dinos, long-necked sauropods, to lumber into dominance (SN: 11/17/20). More

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      ‘Ice Rivers’ invites you to get to know our world’s melting glaciers

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      Ice RiversJemma WadhamPrinceton Univ., $26.95

      I’ve always been a sucker for glacier lingo, whimsical words for a harsh landscape gouged, smoothed and bulldozed by ice. Moulins, drumlins, eskers and moraines. Cirques and arêtes. Cold katabatic winds blowing down a mountain, huffed from a glacier’s snout and said to be its spirit.

      Jemma Wadham’s Ice Rivers: A Story of Glaciers, Wilderness, and Humanity leans into this duality of whimsy and harshness, cheerfully pulling readers into this strange, icy world. Wadham, a glaciologist at the University of Bristol in England, confesses that her goal is to give readers a sense of connection to glaciers, which she knowingly anthropomorphizes: In her writing, glaciers have heavy bodies, dirty snouts and veins filled with water.

      “When I’m with them, I feel like I’m among friends,” she writes. “It is, in many ways, a love story.” And knowing the glaciers, she reasons — perhaps coming to love them — is key to trying to save them.

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      Accordingly, the book’s chapters are anchored by site, and each chapter documents a different field expedition or series of expeditions to a particular glacier. Wadham takes us from the Swiss Alps to Norway’s Svalbard islands, from India’s Himalayas to Antarctica’s McMurdo Dry Valleys. It’s a breezy read, with an eager party host vibe (“let me introduce to you my friend the glacier; I think you two will get along”).

      While describing each site, Wadham dives into an engaging mishmash of personal recollections about her fieldwork, snippets of accessible glacier and climate science (I now know that these rivers of ice have three different manners of flow), a dash of alpine and polar exploration history, and many bits of local color. Ötzi the 5,300-year-old iceman, Erik the Red, Svalbard’s many polar bears and wild Patagonian horses all make an appearance, not to mention the mummified corpses of seals and penguins littering the Dry Valleys (SN: 7/12/18).

      An interesting thread winding through the book concerns how the focus of glaciology as a field has shifted through time. After several years of not winning grants that would allow her to continue working on Svalbard, in 2008 Wadham got the opportunity to go to Greenland instead. “Valley glaciers were no longer considered quite as cutting-edge to the research council funders,” she writes. “Instead, glaciologists had become obsessed with the vast ice sheets,” for the potential of their meltwaters to raise sea levels and alter ocean currents. Several years later, funders began to call for projects looking at melting glaciers’ impacts on ocean life and the water cycle, opening up an opportunity for Wadham to study Patagonia’s fast-changing glacial region.

      Where the book really comes alive is in its vivid snapshots of a scientist’s life in the field: making a bleary-eyed cup of coffee in Patagonia using a thin sock as a filter; fearfully skittering across fragile fjord ice on a Ski-Doo; consuming tins of bland fiskeboller, or fish balls, which were mostly used for food but sometimes for rifle practice; solo dancing away a gray mood on a pebbly beach on Svalbard, with a rifle ready to repel polar bears resting nearby on the stones.

      These recollections are honest, funny and poignant, and reveal how the highs and lows of fieldwork are inextricably intertwined. Wadham writes, for example, of dreading the “hollow feeling caused by constant sleep deprivation” due to the midnight sun and the relentless roaring of winds and water, a feeling tempered by her fierce love for the open expanses of the wild and for pursuing a “big mission.”

      She also writes wistfully of the “communal mirth of field-camp life” where she had never laughed as much before and, less wistfully, of the heavy, claustrophobic atmosphere of an Antarctic research station with its supercharged heating system and extreme politeness over meals with strangers. Against the backdrop of Patagonia’s swiftly shrinking glaciers, Wadham comes to grips with difficult personal losses, even as she wrestles with mysterious headaches. Months later, while recovering from emergency brain surgery, she secretly begins to write about her glaciers. Still more months pass before she finds her way back to the ice, this time in the Peruvian Andes.

      “I quickly realized one key thing about fieldwork — if you think you are there to work, you’re gravely mistaken,” Wadham writes. “You’re actually there to survive, and perform some research along the way — if you’re lucky.… In some ways I found all this ‘surviving’ a grounding process.”

      Every glacier Wadham has studied has shrunk since she first set foot on the ice over a quarter century ago. But Ice Rivers isn’t focused on mourning those glaciers so much as on celebrating the peace and purpose — the grounding line — Wadham found in them. It certainly makes me want to know them better.

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      Rice feeds half the world. Climate change’s droughts and floods put it at risk

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      Under a midday summer sun in California’s Sacramento Valley, rice farmer Peter Rystrom walks across a dusty, barren plot of land, parched soil crunching beneath each step.

      In a typical year, he’d be sloshing through inches of water amid lush, green rice plants. But today the soil lies naked and baking in the 35˚ Celsius (95˚ Fahrenheit) heat during a devastating drought that has hit most of the western United States. The drought started in early 2020, and conditions have become progressively drier.

      Low water levels in reservoirs and rivers have forced farmers like Rystrom, whose family has been growing rice on this land for four generations, to slash their water use.

      Rystrom stops and looks around. “We’ve had to cut back between 25 and 50 percent.” He’s relatively lucky. In some parts of the Sacramento Valley, depending on water rights, he says, farmers received no water this season.

      California is the second-largest U.S. producer of rice, after Arkansas, and over 95 percent of California’s rice is grown within about 160 kilometers of Sacramento. To the city’s east rise the peaks of the Sierra Nevada, which means “snowy mountains” in Spanish. Rice growers in the valley below count on the range to live up to its name each winter. In spring, melting snowpack flows into rivers and reservoirs, and then through an intricate network of canals and drainages to rice fields that farmers irrigate in a shallow inundation from April or May to September or October.

      If too little snow falls in those mountains, farmers like Rystrom are forced to leave fields unplanted. On April 1 this year, the date when California’s snowpack is usually at its deepest, it held about 40 percent less water than average, according to the California Department of Water Resources. On August 4, Lake Oroville, which supplies Rystrom and other local rice farmers with irrigation water, was at its lowest level on record.

      Drought in the Sacramento Valley has forced Peter Rystrom and other rice farmers to leave swaths of land barren.N. Ogasa

      Not too long ago, the opposite — too much rain — stopped Rystrom and others from planting. “In 2017 and 2019, we were leaving ground out because of flood. We couldn’t plant,” he says. Tractors couldn’t move through the muddy, clay-rich soil to prepare the fields for seeding.

      Climate change is expected to worsen the state’s extreme swings in precipitation, researchers reported in 2018 in Nature Climate Change. This “climate whiplash” looms over Rystrom and the other 2,500 or so rice producers in the Golden State. “They’re talking about less and less snowpack, and more concentrated bursts of rain,” Rystrom says. “It’s really concerning.”

      Farmers in China, India, Bangladesh, Indonesia, Vietnam — the biggest rice-growing countries — as well as in Nigeria, Africa’s largest rice producer — also worry about the damage climate change will do to rice production. More than 3.5 billion people get 20 percent or more of their calories from the fluffy grains. And demand is increasing in Asia, Latin America and especially in Africa.

      To save and even boost production, rice growers, engineers and researchers have turned to water-saving irrigation routines and rice gene banks that store hundreds of thousands of varieties ready to be distributed or bred into new, climate-resilient forms. With climate change accelerating, and researchers raising the alarm about related threats, such as arsenic contamination and bacterial diseases, the demand for innovation grows.

      “If we lose our rice crop, we’re not going to be eating,” says plant geneticist Pamela Ronald of the University of California, Davis. Climate change is already threatening rice-growing regions around the world, says Ronald, who identifies genes in rice that help the plant withstand disease and floods. “This is not a future problem. This is happening now.”

      Saltwater woes

      Most rice plants are grown in fields, or paddies, that are typically filled with around 10 centimeters of water. This constant, shallow inundation helps stave off weeds and pests. But if water levels suddenly get too high, such as during a flash flood, the rice plants can die.

      Striking the right balance between too much and too little water can be a struggle for many rice farmers, especially in Asia, where over 90 percent of the world’s rice is produced. Large river deltas in South and Southeast Asia, such as the Mekong River Delta in Vietnam, offer flat, fertile land that is ideal for farming rice. But these low-lying areas are sensitive to swings in the water cycle. And because deltas sit on the coast, drought brings another threat: salt.

      Salt’s impact is glaringly apparent in the Mekong River Delta. When the river runs low, saltwater from the South China Sea encroaches upstream into the delta, where it can creep into the soils and irrigation canals of the delta’s rice fields.

      In Vietnam’s Mekong River Delta, farmers pull dead rice plants from a paddy that was contaminated by saltwater intrusion from the South China Sea, which can happen during a drought.HOANG DINH NAM/AFP VIA GETTY IMAGES

      “If you irrigate rice with water that’s too salty, especially at certain [growing] stages, you are at risk of losing 100 percent of the crop,” says Bjoern Sander, a climate change specialist at the International Rice Research Institute, or IRRI, who is based in Vietnam.

      In a 2015 and 2016 drought, saltwater reached up to 90 kilometers inland, destroying 405,000 hectares of rice paddies. In 2019 and 2020, drought and saltwater intrusion returned, damaging 58,000 hectares of rice. With regional temperatures on the rise, these conditions in Southeast Asia are expected to intensify and become more widespread, according to a 2020 report by the Economic and Social Commission for Asia and the Pacific.

      Then comes the whiplash: Each year from around April to October, the summer monsoon turns on the faucet over swaths of South and Southeast Asia. About 80 percent of South Asia’s rainfall is dumped during this season and can cause destructive flash floods.

      Bangladesh is one of the most flood-prone rice producers in the region, as it sits at the mouths of the Ganges, Brahmaputra and Meghna rivers. In June 2020, monsoon rains flooded about 37 percent of the country, damaging about 83,000 hectares of rice fields, according to Bangladesh’s Ministry of Agriculture. And the future holds little relief; South Asia’s monsoon rainfall is expected to intensify with climate change, researchers reported June 4 in Science Advances.

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      A hot mess

      Water highs and lows aren’t the entire story. Rice generally grows best in places with hot days and cooler nights. But in many rice-growing regions, temperatures are getting too hot. Rice plants become most vulnerable to heat stress during the middle phase of their growth, before they begin building up the meat in their grains. Extreme heat, above 35˚ C, can diminish grain counts in just weeks, or even days. In April in Bangladesh, two consecutive days of 36˚ C destroyed thousands of hectares of rice.

      In South and Southeast Asia, such extreme heat events are expected to become common with climate change, researchers reported in July in Earth’s Future. And there are other, less obvious, consequences for rice in a warming world.

      One of the greatest threats is bacterial blight, a fatal plant disease caused by the bacterium Xanthomonas oryzae pv. oryzae. The disease, most prevalent in Southeast Asia and rising in Africa, has been reported to have cut rice yields by up to 70 percent in a single season.

      “We know that with higher temperature, the disease becomes worse,” says Jan Leach, a plant pathologist at Colorado State University in Fort Collins. Most of the genes that help rice combat bacterial blight seem to become less effective when temperatures rise, she explains.

      And as the world warms, new frontiers may open for rice pathogens. An August study in Nature Climate Change suggests that as global temperatures rise, rice plants (and many other crops) at northern latitudes, such as those in China and the United States, will be at higher risk of pathogen infection.

      Meanwhile, rising temperatures may bring a double-edged arsenic problem. In a 2019 study in Nature Communications, E. Marie Muehe, a biogeochemist at the Helmholtz Centre for Environmental Research in Leipzig, Germany, who was then at Stanford University, showed that under future climate conditions, more arsenic will infiltrate rice plants. High arsenic levels boost the health risk of eating the rice and impair plant growth.

      Arsenic naturally occurs in soils, though in most regions the toxic element is present at very low levels. Rice, however, is particularly susceptible to arsenic contamination, because it is grown in flooded conditions. Paddy soils lack oxygen, and the microbes that thrive in this anoxic environment liberate arsenic from the soil. Once the arsenic is in the water, rice plants can draw it in through their roots. From there, the element is distributed throughout the plants’ tissues and grains.

      Muehe and her team grew a Californian variety of rice in a local low-arsenic soil inside climate-controlled greenhouses. Increasing the temperature and carbon dioxide levels to match future climate scenarios enhanced the activity of the microbes living in the rice paddy soils and increased the amount of arsenic in the grains, Muehe says. And importantly, rice yields diminished. In the low-arsenic Californian soil under future climate conditions, rice yield dropped 16 percent.

      According to the researchers, models that forecast the future production of rice don’t account for the impact of arsenic on harvest yields. What that means, Muehe says, is that current projections are overestimating how much rice will be produced in the future.

      Managing rice’s thirst

      From atop an embankment that edges one of his fields, Rystrom watches water gush from a pipe, flooding a paddy packed with rice plants. “On a year like this, we decided to pump,” he says.

      Able to tap into groundwater, Rystrom left only about 10 percent of his fields unplanted this growing season. “If everybody was pumping from the ground to farm rice every year,” he admits, it would be unsustainable.

      One widely studied, drought-friendly method is “alternate wetting and drying,” or intermittent flooding, which involves flooding and draining rice paddies on one- to 10-day cycles, as opposed to maintaining a constant inundation. This practice can cut water use by up to 38 percent without sacrificing yields. It also stabilizes the soil for harvesting and lowers arsenic levels in rice by bringing more oxygen into the soils, disrupting the arsenic-releasing microbes. If tuned just right, it may even slightly improve crop yields.

      But the water-saving benefits of this method are greatest when it is used on highly permeable soils, such as those in Arkansas and other parts of the U.S. South, which normally require lots of water to keep flooded, says Bruce Linquist, a rice specialist at the University of California Cooperative Extension. The Sacramento Valley’s clay-rich soils don’t drain well, so the water savings where Rystrom farms are minimal; he doesn’t use the method.

      Building embankments, canal systems and reservoirs can also help farmers dampen the volatility of the water cycle. But for some, the solution to rice’s climate-related problems lies in enhancing the plant itself.

      Fourth-generation rice farmer Peter Rystrom (left) stands with his grandfather Don Rystrom (middle) and his father Steve Rystrom (right).CALIFORNIA RICE COMMISSION, BRIAN BAER

      Better breeds

      The world’s largest collection of rice is stored near the southern rim of Laguna de Bay in the Philippines, in the city of Los Baños. There, the International Rice Genebank, managed by IRRI, holds over 132,000 varieties of rice seeds from farms around the globe.

      Upon arrival in Los Baños, those seeds are dried and processed, placed in paper bags and moved into two storage facilities — one cooled to 2˚ to 4˚ C from which seeds can be readily withdrawn, and another chilled to –20˚ C for long-term storage. To be extra safe, backup seeds are kept at the National Center for Genetic Resources Preservation in Fort Collins, Colo., and the Svalbard Global Seed Vault tucked inside a mountain in Norway.

      All this is done to protect the biodiversity of rice and amass a trove of genetic material that can be used to breed future generations of rice. Farmers no longer use many of the stored varieties, instead opting for new higher-yield or sturdier breeds. Nevertheless, solutions to climate-related problems may be hidden in the DNA of those older strains. “Scientists are always looking through that collection to see if genes can be discovered that aren’t being used right now,” says Ronald, of UC Davis. “That’s how Sub1 was discovered.”

      Over 132,000 varieties of rice seeds fill the shelves of the climate-controlled International Rice Genebank. Breeders from around the world can use the seeds to develop new climate-resilient rice strains.IRRI/FLICKR (CC BY-NC-SA 2.0)

      The Sub1 gene enables rice plants to endure prolonged periods completely submerged underwater. It was discovered in 1996 in a traditional variety of rice grown in the Indian state of Orissa, and through breeding has been incorporated into varieties cultivated in flood-prone regions of South and Southeast Asia. Sub1-wielding varieties, called “scuba rice,” can survive for over two weeks entirely submerged, a boon for farmers whose fields are vulnerable to flash floods.

      Some researchers are looking beyond the genetic variability preserved in rice gene banks, searching instead for useful genes from other species, including plants and bacteria. But inserting genes from one species into another, or genetic modification, remains controversial. The most famous example of genetically modified rice is Golden Rice, which was intended as a partial solution to childhood malnutrition. Golden Rice grains are enriched in beta-carotene, a precursor to vitamin A. To create the rice, researchers spliced a gene from a daffodil and another from a bacterium into an Asian variety of rice.

      Three decades have passed since its initial development, and only a handful of countries have deemed Golden Rice safe for consumption. On July 23, the Philippines became the first country to approve the commercial production of Golden Rice. Abdelbagi Ismail, principal scientist at IRRI, blames the slow acceptance on public perception and commercial interests opposed to genetically modified organisms, or GMOs (SN: 2/6/16, p. 22).

      Looking ahead, it will be crucial for countries to embrace GM rice, Ismail says. Developing nations, particularly those in Africa that are becoming more dependent on the crop, would benefit greatly from the technology, which could produce new varieties faster than breeding and may allow researchers to incorporate traits into rice plants that conventional breeding cannot. If Golden Rice were to gain worldwide acceptance, it could open the door for new genetically modified climate- and disease-resilient varieties, Ismail says. “It will take time,” he says. “But it will happen.”

      Climate change is a many-headed beast, and each rice-growing region will face its own particular set of problems. Solving those problems will require collaboration between local farmers, government officials and the international community of researchers.

      “I want my kids to be able to have a shot at this,” Rystrom says. “You have to do a lot more than just farm rice. You have to think generations ahead.” More

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      Australian fires in 2019–2020 had even more global reach than previously thought

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      The severe, devastating wildfires that raged across southeastern Australia in late 2019 and early 2020 packed a powerful punch that extended far beyond the country, two new studies find.

      The blazes injected at least twice as much carbon dioxide into the atmosphere as was previously thought, one team’s satellite-derived estimates revealed. The fires also sent up vast clouds of smoke and ash that wafted far to the east over the Southern Ocean, fertilizing the waters with nutrients and triggering widespread blooms of microscopic marine algae called phytoplankton, another team found. Both studies were published online September 15 in Nature.

      Meteorologist Ivar van der Velde of the SRON Netherlands Institute for Space Research in Leiden and colleagues first examined carbon monoxide data collected over southeastern Australia by the satellite-based instrument TROPOMI from November 2019 to January 2020, during the worst of the fires. Then, to get new estimates of the carbon dioxide emissions attributable to the fires, the team used previously determined ratios of carbon monoxide to carbon dioxide emitted by the region’s eucalyptus forests — the predominant type of forest that was scorched in the blazes — during earlier wildfires and prescribed burns.

      Van der Velde’s team estimates that the fires released from 517 trillion to 867 trillion grams of carbon dioxide to the atmosphere. “The sheer magnitude of CO2 that was emitted to the atmosphere … was much larger than what we initially thought it would be,” van der Velde says. The emissions “from this single event were significantly higher than what all Australians normally emit with the combustion of fossil fuels in an entire year.”

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      Previous assessments of CO2 emissions from the fires, based on estimations of burned area and biomass consumed by the blazes, calculated an average of about 275 trillion grams. Using the satellite-derived carbon monoxide data, the researchers say, dramatically improves the ability to distinguish actual emissions from the fires from other background sources of the gases, giving a more accurate assessment.

      That finding has worrisome implications. The fires swiftly cut a swath through southeastern Australia’s eucalyptus forests, devastating the forests to a degree that made their rapid recovery more difficult — which in turn affects how much carbon the trees can sequester, van der Velde says (SN: 3/9/21). Fires in northern and central Australia’s dry, grassy savannas are seen as more climate neutral because the grasses can regrow more quickly, he says.

      And severe fire seasons are likely to become more common in southeastern Australia with ongoing climate change. Climate change has already increased the likelihood of severe fire events such as the 2019–2020 fire season by at least 30 percent (SN: 3/4/20).

      The smoke and ash from the fires also packed a powerful punch. Scientists watched in awe as the fires created a “super outbreak” of towering thunderclouds from December 29 to December 31 in 2019 (SN: 12/15/20). These clouds spewed tiny aerosol particles of ash and smoke high into the stratosphere.

      Aerosols from the fires also traveled eastward through the lower atmosphere, ultimately reaching the Southern Ocean where they triggered blooms of phytoplankton in its iron-starved waters. Geochemist Weiyi Tang, now at Princeton University, and colleagues analyzed aerosols from the fires and found the particles to be rich in iron, an important nutrient for the algae. By tracing the atmospheric paths of the cloud of ash and smoke across the ocean, the team was able to link the observed blooms — huge patches of chlorophyll detected by satellite — to the fires.

      A satellite image snapped on January 6, 2020, shows smoke from southeastern Australia’s wildfires wafting eastward over the Southern Ocean.Japan’s National Institute of Information and Communication Technology

      Researchers have long thought that fires can trigger ocean blooms, particularly in the Southern Ocean, under the right conditions, says marine biogeochemist Joan Llort, now at the Barcelona Supercomputing Center and a coauthor on the study. But this research marks the most direct observation ever made of such an event — in part because it was such a massive one, Llort says.

      Large ocean blooms are “yet another process which is potentially being modified by climate change,” says biogeochemist Nicolas Cassar of Duke University, also a coauthor on the study.

      One of the big questions to emerge from the study, Cassar adds, is just how much carbon these phytoplankton may have ultimately removed from the atmosphere as they bloomed. Some of the carbon that the algae draw out of the air through photosynthesis sinks with them to the seafloor as they die. But some of it is quickly respired back to the atmosphere, muting any mitigating effect that the blooms might have on the wildfire emissions. To really assess what role the algae play, he says, would require a rapid-response team aboard an ocean vessel that could measure these chemical processes as they are happening.

      The sheer size of this wildfire-triggered bloom — “larger than Australia itself” — shows that “wildfires have the potential to increase marine productivity by very large amounts,” says Douglas Hamilton, a climate scientist at Cornell University who was not connected with the study.

      “The impact of fires on society is not straightforward,” Hamilton adds. The same smoke that can cause severe health impacts when inhaled “is also supplying nutrients to ecosystems and helping support marine food webs.” What this study demonstrates, he adds, is that to understand how future increases in fire activity might help shape the future of marine productivity “it is crucial that we monitor the impacts closely now.” More

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      Potty-trained cattle could help reduce pollution

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      You can lead a cow to a water closet, but can you make it pee there? It turns out that yes, you can.

      Researchers in Germany successfully trained cows to use a small, fenced-in area with artificial turf flooring as a bathroom stall. This could allow farms to easily capture and treat cow urine, which often pollutes air, soil and water, researchers report online September 13 in Current Biology. Components of that urine, such as nitrogen and phosphorus, could also be used to make fertilizer (SN: 4/6/21).

      The average cow can pee tens of liters per day, and there are some 1 billion cattle worldwide. In barns, cow pee typically mixes with poop on the floor to create a slurry that emits the air pollutant ammonia (SN: 1/4/19). Out in pastures, cow pee can leach into nearby waterways and release the potent greenhouse gas nitrous oxide (SN: 6/9/14).

      “I’m always of the mind, how can we get animals to help us in their management?” says Lindsay Matthews, a self-described cow psychologist who studies animal behavior at the University of Auckland in New Zealand. Matthews and colleagues set out to potty train 16 calves, which had the free time to learn a new skill. “They’re not so involved with milking and other systems,” he says. “They’re basically just hanging out, eating a bit of food, socializing and resting.”

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      Matthews was optimistic about the cows’ potty-training prospects. “I was convinced that we could do it,” he says. Cows “are much, much smarter than people give them credit for.” Each calf got 45 minutes of what the team calls “MooLoo training” per day. At first, the researchers enclosed the calves inside the makeshift bathroom stall and fed the animals a treat every time they peed.

      Once the calves made the connection between using the bathroom stall and receiving a treat, the team positioned the calves in a hallway leading to the stall. Whenever animals visited the little cows’ room, they got a treat; whenever calves peed in the hallway, the team spritzed them with water. “We had 11 of the 16 calves [potty trained] within about 10 days,” Matthews says. The remaining cows “are probably trainable too,” he adds. “It’s just that we didn’t have enough time.”

      [embedded content]
      Researchers successfully trained 11 calves, such as this one, to urinate in a bathroom stall. Once the cow relieved itself, a window in the stall opened, dispensing a molasses mixture as a treat. Toilet training cows on a large scale and collecting their urine to make fertilizer could cut down on agricultural pollution, the team says.

      Lindsay Whistance, a livestock researcher at the Organic Research Centre in Cirencester, England, is “not surprised by the results.” With proper training and motivation, “I fully expected cattle to be able to learn this task,” says Whistance, who was not involved in the study. The practicality of potty training cows on a large scale, she says, is another matter.

      For MooLoo training to become a widespread practice, “it has to be automated,” Matthews says. “We want to develop automated training systems, automated reward systems.” Those systems are still far from reality, but Matthews and colleagues hope they could have big impacts. If 80 percent of cow pee were collected in latrines, for instance, that could cut associated ammonia emissions in half, previous research suggests.

      “It’s those ammonia emissions that are key to the real environmental benefit, as well as potential for reducing water contamination,” says Jason Hill, a biosystems engineer at the University of Minnesota in St. Paul not involved in the work. “Ammonia from cattle is a major contributor to reduced human health,” he says (SN: 1/16/09). So potty training cattle could help create cleaner air — as well as a cleaner, more comfortable living space for cows themselves. More

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      How AI can help forecast how much Arctic sea ice will shrink

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      In the next week or so, the sea ice floating atop the Arctic Ocean will shrink to its smallest size this year, as summer-warmed waters eat away at the ice’s submerged edges.

      Record lows for sea ice levels will probably not be broken this year, scientists say. In 2020, the ice covered 3.74 million square kilometers of the Arctic at its lowest point, coming nail-bitingly close to an all-time record low. Currently, sea ice is present in just under 5 million square kilometers of Arctic waters, putting it on track to become the 10th-lowest extent of sea ice in the area since satellite record keeping began in 1979. It’s an unexpected finish considering that in early summer, sea ice hit a record low for that time of year.

      The surprise comes in part because the best current statistical- and physics-based forecasting tools can closely predict sea ice extent only a few weeks in advance, but the accuracy of long-range forecasts falters. Now, a new tool that uses artificial intelligence to create sea ice forecasts promises to boost their accuracy — and can do the analysis relatively quickly, researchers report August 26 in Nature Communications.

      IceNet, a sea ice forecasting system developed by the British Antarctic Survey, or BAS, is “95 percent accurate in forecasting sea ice two months ahead — higher than the leading physics-based model SEAS5 — while running 2,000 times faster,” says Tom Andersson, a data scientist with BAS’s Artificial Intelligence lab. Whereas SEAS5 takes about six hours on a supercomputer to produce a forecast, IceNet can do the same in less than 10 seconds on a laptop. The system also shows a surprising ability to predict anomalous ice events — unusual highs or lows — up to four months in advance, Andersson and his colleagues found.

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      Tracking sea ice is crucial to keeping tabs on the impacts of climate change. While that’s more of a long game, the advanced notice provided by IceNet could have more immediate benefits, too. For instance, it could give scientists the lead time needed to assess, and plan for, the risks of Arctic fires or wildlife-human conflicts, and it could provide data that Indigenous communities need to make economic and environmental decisions.

      Arctic sea ice extent has steadily declined in all seasons since satellite records began in 1979 (SN: 9/25/19). Scientists have been trying to improve sea ice forecasts for decades, but success has proved elusive. “Forecasting sea ice is really hard because sea ice interacts in complex ways with the atmosphere above and ocean below,” Andersson says.

      [embedded content]
      In 2020, the sea ice in the Arctic shrank to its second lowest extent since satellite monitoring began in 1979. This animation uses those observations to show the change in sea ice coverage from March 5, when the ice was at its maximum, through September 15, when the ice reached its lowest point. The yellow line represents the average minimum extent from 1981 to 2010. Current forecasting tools can accurately predict these changes weeks in advance. A new AI-based tool can predict these changes with nearly 95 percent accuracy several months in advance.

      Existing forecast tools put the laws of physics into computer code to predict how sea ice will change in the future. But partly due to uncertainties in the physical systems governing sea ice, these models struggle to produce accurate long-range forecasts.

      Using a process called deep learning, Andersson and his colleagues loaded observational sea ice data from 1979 to 2011 and climate simulations covering 1850 to 2100 to train IceNet how to predict the state of future sea ice by processing the data from the past.

      To determine the accuracy of its forecasts, the team compared IceNet’s outputs to the observed sea ice extent from 2012 to 2020, and to the forecasts made by SEAS5, the widely cited tool used by the European Centre for Medium-Range Weather Forecasts. IceNet was as much as 2.9 percent more accurate than SEAS5, corresponding to a further 360,000 square kilometers of ocean being correctly labeled as “ice” or “no ice.”

      What’s more, in 2012, a sudden crash in summer sea ice extent heralded a new record low extent in September of that year. In running through past data, IceNet saw the dip coming months in advance. SEAS5 had inklings too but its projections that far out were off by a few hundred thousand square kilometers.

      “This is a significant step forward in sea ice forecasting, boosting our ability to produce accurate forecasts that were typically not thought possible and run them thousands of times faster,” says Andersson. He believes it’s possible that IceNet has better learned the physical processes that determine the evolution of sea ice from the training data while physics-based models still struggle to understand this information.

      “These machine learning techniques have only begun contributing to [forecasting] in the last couple years, and they’ve been doing amazingly well,” says Uma Bhatt, an atmospheric scientist at the University of Alaska Fairbanks Geophysical Institute who was not involved in the new study. She also leads the Sea Ice Prediction Network, a group of multidisciplinary scientists working to improve forecasting.

      Bhatt says that good seasonal ice forecasts are important for assessing the risk of Arctic wildfires, which are tied strongly to the presence of sea ice (SN: 6/23/20). “Knowing where the sea ice is going to be in the spring could potentially help you figure out where you’re likely to have fires — in Siberia, for example, as soon as the sea ice moves away from the shore, the land can warm up very quickly and help set the stage for a bad fire season.”

      Any improvement in sea ice forecasting can also help economic, safety and environmental planning in northern and Indigenous communities. For example, tens of thousands of walruses haul out on land to rest when the sea ice disappears (SN: 10/2/14). Human disturbances can trigger deadly stampedes and lead to high walrus mortality. With seasonal ice forecasts, biologists can anticipate rapid ice loss and manage haul-out sites in advance by limiting human access to those locations.

      Still, limitations remain. At four months of lead time, the system was about 91 percent accurate in predicting the location of September’s ice edge.IceNet, like other forecasting systems, struggles to produce accurate long-range forecasts for late summer due, in part, to what scientists call the “spring predictability barrier.” It’s crucial to know the condition of the sea ice at the start of the spring melting season to be able to forecast end-of-summer conditions.

      Another limit is “the fact that the weather is so variable,” says Mark Serreze, director of the National Snow and Ice Data Center in Boulder, Colo. Though sea ice seemed primed to set a new annual record low at the start of July, the speed of ice loss ultimately slowed due to cool atmospheric temperatures. “We know that sea ice responds very strongly to summer weather patterns, but we can’t get good weather predictions. Weather predictability is about 10 days in advance.” More