Stormy rains in the Sahara offer clues to past and future climate changes

The Hebrew University of Jerusalem

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The normally dry northwestern Sahara lake, Sebkha el Melah, was filled for the seventh time since the beginning of the 21st century. This flood, in September 2024, which occurred after the study was conducted, happened because of heavy precipitation in the Sahara associated with the same atmospheric patterns described in the paper, in which Atlantic moisture is driven far into the desert. Landsat 9 imagery is from the NASA Worldview application (https://worldview.earthdata.nasa.gov), part of the NASA Earth Science Data and Information System (ESDIS).

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Credit: Moshe Armon

New research reveals that heavy precipitation sourced from the Atlantic Ocean, are the primary drivers of present-day lake filling in the northwestern Sahara. The study finds that only the most intense and prolonged precipitation events trigger lake-filling episodes, challenging long-standing assumptions about past climate conditions in the region. These findings suggest that projections of enhanced rainfall intensity and frequency in the Sahara could potentially reshape water availability in the desert.

A new study supervised by Dr. Moshe Armon from the Institute of Earth Sciences at Hebrew University and Dr. Franziska Aemisegger from University of Bern, in collaboration with Dr. Elad Dente from University of Haifa, led by their student Joëlle Rieder at ETH Zurich, recently published in Hydrology and Earth System Sciences, provides new insights into the meteorological processes responsible for the filling of a normally dry lake in the northwestern Sahara. The research offers a fresh perspective on past climate variations and suggests we can learn from past flooding of the lake on ongoing climate change and future water resources in the desert.

The Sahara Desert, one of the driest places on Earth, has not always been as arid as it is today. Prehistoric evidence of wetlands in the Sahara points to wetter periods in the past, but scientists have long debated the sources of moisture responsible for these ancient water bodies. The study examines how the currently dry Sebkha El-Melah lake in western Algeria is occasionally filled with water, shedding light on the extreme storm events required to sustain such bodies of water.

Key Findings:
•    Between 2000 and 2021, hundreds of powerful rainstorms were recorded in the lake’s drainage basin, yet only six instances led to substantial lake-filling events.
•    These lake-filling events were driven by precipitation systems originating from the Atlantic Ocean, rather than equatorial sources as previously believed.
•    The moisture transport process involves the interaction of extratropical cyclones near the North African Atlantic coast with upper-level atmospheric patterns, creating conditions favorable for heavy precipitation events.
•    A crucial factor in these events is the recycling-domino effect, in which moisture is progressively transported and enhanced over the Sahara before reaching the lake’s drainage basin.
•    The stationarity of weather systems, lasting typically three days, contributes significantly to the occurrence of lake-filling events.

This research challenges conventional theories suggesting that prehistoric lakes in the Sahara were primarily filled by monsoonal rains from the south. Instead, it highlights the role of Atlantic-origin storms, which deliver oceanic moisture into the desert, bypassing the Atlas Mountains. These findings have important implications for understanding past climate conditions and predicting future hydrological changes in desert environments.

The study further suggests that potential future climate shifts—driven by global warming—have the potential to fill Saharan lakes not only due to increased rainfall, but also because of changes in the frequency of extreme rainstorms. This could reshape water availability in the region, with significant consequences for ecosystems and human settlements.

By integrating climate science, meteorology, remote sensing, and hydrology, this research bridges a critical knowledge gap and provides a framework for future studies on Sahara Desert hydrology and climate dynamics.
 

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Journal

Hydrology and Earth System Sciences

DOI

10.5194/hess-29-1395-2025 

Method of Research

Data/statistical analysis

Subject of Research

Not applicable

Article Title

Meteorological ingredients of heavy precipitation and subsequent lake-filling episodes in the northwestern Sahara

Article Publication Date

17-Mar-2025

 

Scientists discover protein key to bacteria’s survival in extreme environments

The discovery sheds light on how certain bacteria – including strains that cause food poisoning and anthrax – form spores for survival

King's College London

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Scientists have discovered a protein that enables bacteria to shut down into dormant spores under extreme conditions. The process, which enables the bacteria to become practically indestructible, explains why bacteria can survive in uninhabitable places such as under the permafrost, in the depths of the ocean or in outer space.  

 

This ability to sporulate, known as sporulation, also enables superbugs to evade hospital cleaning and then come back to life in the guts of compromised patients.  

 

By discovering a new protein involved in sporulation in a group of bacteria, scientists hope it could deepen our understanding of bacteria’s ability to survive against the odds, and even open up new avenues for antimicrobial therapies.  

 

The study, covered in two separate papers published in Genes and Development today, looks at Bacillus – a group of bacteria including cereus, which is responsible for food poisoning, and anthrax. The research team included scientists from the Department of Chemistry, King’s College London, the University of California San Diego, the Max Planck Unit for the Science of Pathogens in Berlin, and Mount Holyoke College in the USA.  

 

Professor Rivka Isaacson, co-author of the papers, said: “We have known for a long time that bacteria are able to perform metabolic shut-down in unfavourable environments, transforming into long-lived, indestructible dormant spores which can survive for thousands of years.” 

 

“This happens through asymmetrical cell division, where the bigger part – the ‘mother cell’ - engulfs the smaller part, the ‘forespore’, providing it with nutrients and a protective outer layer. It continues to build up protective layers around its genetic materials until it is ready to be released as a spore.”  

 

Whilst this process is well understood, the mechanisms behind shutting down metabolism have remained a mystery until the scientists discovered a previously uncharacterised protein called MdfA was behind it.  

 

Professor Isaacson explained: “Every cell has a ‘recycling centre’ called a protease, responsible for breaking down old or damaged proteins. We discovered that MdfA – a protein we didn’t know the function of previously, acts as an adaptor that recruits the proteins for recycling.  

 

“In the case of sporulation, this protein instructs the cell to get rid of its metabolic enzymes responsible for active growth, by destruction through the protease, thereby effecting the metabolic shutdown part of sporulation.” 

 

Once MdfA had been identified, chemists at King’s were able to solve the crystal structure of the protein using x-ray crystallography, revealing a completely new molecular shape. This has enabled them to further understand how MdfA binds to a part of the recycling chute in cells, a protein called ClpC. 

 

 

The scientists also found that when they forced happily growing cells to overexpress MdfA, it became toxic to the cells and they burst.  

 

Whilst MdfA isn’t present in most other forms of bacteria, ClpC and the recycling machine is, so similar proteins may be behind sporulation in other bacteria, including those that cause disease. 

 

Professor Isaacson said: “This discovery has improved our understanding of how bacteria operate and opens up a new way of exploring sporulation. Given that sporulation plays a key part in bacteria’s survival, the more we understand this process, the more we will be able to control and eliminate harmful bacteria.”  

  

The scientists also hope their findings might lead to new strategies for developing antimicrobials. 

 

Professor Isaacson added: “If you can target the cell degradation machinery to remove particular proteins, this can open new avenues for anti-microbial therapies, similar to an emerging form of cancer treatment, known as targeted protein degradation or PROTAC, which repurposes a cell’s recycling system for therapy.” 

 

 

 

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DOI

10.1101/gad.352498.124 

 

Climate change fuelling mental health crisis in areas most affected by climate crisis

Young people in southern Madagascar report extremely high levels of anxiety, depression, and sense of hopelessness

Trinity College Dublin

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Climate change is not just an environmental issue — it’s a mental health crisis impacting on adolescent wellbeing right now in areas most affected by climate change, according to new research from Trinity College Dublin.

The authors of the study published this week in the Journal of Climate Change and Health have called for mental health supports to be built into climate adaptation efforts to help young people facing an uncertain future.

We already know that climate change is threatening child and adolescent health worldwide, but there is limited research on its effects on mental health in the low- and middle-income countries that are most affected by climate crisis. 

The study reveals that climate change is having a severe impact on adolescent mental health in southern Madagascar. The mixed-methods study gathered survey data from 83 adolescents and focus groups with 48 participants across six rural villages in March 2024.

Young people in the region report extremely high levels of anxiety, depression, and climate change worry, with many describing a sense of hopelessness about the future. Participants described feeling powerless, with one adolescent saying, “I have no idea what I can do to be happy” and another indicating “life is a misery”.

“Young people in southern Madagascar are the unwilling pioneers of the impact of climate change. They can provide important insights into the way climate changes impact on adolescent mental health,” explains lead author on the paper Dr Kristin Hadfield, Associate Professor in the School of Psychology and Trinity Centre for Global Health at Trinity College Dublin.

“This research makes it clear that climate change is not just an environmental issue — it is a mental health issue as well. We found that chronic climate stressors — not just extreme weather events — are already shaping adolescent mental health. In higher-income countries, climate anxiety often focuses on future risks, but in Madagascar, young people are already living the reality.” 

The study, conducted led by researchers in Trinity’s School of Psychology with colleagues in the Catholic University of Madagascar, Queen Mary University of London, University College London, and CBM Global, found that climate change affected adolescent mental health through three main pathways: loss of household resources, uncertainty about the future, and disruption of coping mechanisms. 

Food insecurity is particularly severe — 90% of households had run out of food in the past year, and 69% of adolescents had gone an entire day without eating. The mixed-methods study gathered survey data from 83 adolescents and focus groups with 48 participants across six rural villages in March 2024. 

Many expressed deep distress over their families’ struggles, and most had witnessed people in their communities starve to death. As one adolescent put it: "so many died … there were many elders, but they died because of the malnutrition". Another stated simply: "there is no water and when sunlight is burning, we are suffering".

Isabelle Mareschal, School of Biological and Behavioural Sciences, Queen Mary University of London, said: “Young people in developing countries are particularly vulnerable to the effects of climate change. This research finds that we need to also consider how climate change impacts their mental health. We hope that these findings can help inform interventions to improve mental health outcomes, with a focus on young people in low and middle income countries.”

Dr Nambinina Rasolomalala, Catholic University of Madagascar, said: "Adolescents in Androy, southern Madagascar, speak of famine, fear, and futures stolen by drought and sandstorms. With crops failing and water scarce, many adolescents are forced to leave their communities to survive, while those who stay face hunger, lost education, and deep despair."

Satry Ramaroson, Madagascar Country Director for CBM Global, added: "Climate change is causing suffering for children and adolescents in the South of Madagascar. Recurring droughts fuel food crises and loss of hope, with adolescents with disabilities among the most affected."

The full paper, “There is no hope; only strong wind”: How climate change impacts adolescent mental health in southern Madagascar, can be viewed on the Journal of Climate Change and Health’s website.

ENDS

Notes to editors:

Madagascar, an island nation in the Indian Ocean, is one of the least developed countries in the world with a gross national income of US$487 per capita with the population highly dependent on subsistence farming. Children in Madagascar are extremely vulnerable to climate stresses such as water scarcity flooding heat waves disease susceptibility and pollution as well as to more general child vulnerability (for example child and maternal health and nutrition lack of access to education or sanitation and poverty). Southern Madagascar (Grand Sud) is one of the most severely climate change affected areas in the world and the first climate change-induced famine occurred in this region at 2021.

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Journal

The Journal of Climate Change and Health

DOI

10.1016/j.joclim.2025.100438 

Method of Research

Survey

Subject of Research

People

Article Title

“There is no hope; only strong wind”: How climate change impacts adolescent mental health in southern Madagascar

Article Publication Date

17-Mar-2025

 

How to stop being surprised by extreme weather - study

University of Reading

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Helping communities predict extreme weather events that have never been recorded in modern history is the focus of a new study published in Nature Communications.

A team from the Climate Adaptation Services Foundation, the University of Reading and other international institutions has brought together methods to see beyond the limitations of conventional weather records, which typically only cover the past century.

The study reveals how, for example, nature's own archives - like tree rings - combined with forgotten historical documents can unlock centuries of climate data that modern instruments have missed.

Lead author Timo Kelder said: "We've been limited by thinking extreme weather is only as bad as what we've measured since weather stations were invented. But our research shows we can use weather models to look back hundreds or even thousands of years to discover what's truly possible in our climate system."

A toolkit for scientists and practitioners

The researchers identified four approaches that together create a more complete picture of possible extreme weather:

● Analysing conventional records

● Studying historical and natural archives like tree rings

● Creating "what-if" scenarios based on past events

● Using climate models to simulate physically possible extremes

Tree rings proved especially valuable, with each ring preserving a year's worth of climate history. Researchers used these natural time capsules to reconstruct 850 years of drought patterns in northwestern China, revealing extreme events that would have been invisible in modern records.

The team also highlighted forgotten weather extremes by digging through historical archives. They found that June 1846 in Durham, UK was significantly hotter than any modern June temperature. Similarly, September 1774 in Oxford was wetter than any month recorded in the 250 years since.

Adapt, adapt, adapt

The study emphasises that with these methods to anticipate the unseen, communities can better prepare for unprecedented weather. The methods can support three layers of preparation:

● Improved early warning systems

● Upgraded infrastructure

● Transformative social changes to reduce vulnerability

The researchers conclude that by breaking free from the constraints of limited modern records, we can finally stop being surprised by "unprecedented" weather events.

Dorothy Heinrich, co-author at the University of Reading, said : “Unprecedented weather doesn't just break records—it breaks communities, infrastructure, and lives. When the unimaginable happens, being unprepared is a disaster waiting to unfold. But science can help us to imagine the unimaginable, to uncover these risks, and prepare. Our future depends on how quickly and thoroughly we adapt today."

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Journal

Nature Communications

DOI

10.1038/s41467-025-57450-0 

Article Title

How to stop being surprised by unprecedented weather

Article Publication Date

18-Mar-2025

 

Efficient development of drugs with fewer mice

NO MORE ANIMAL TESTING

Animal research and 3R

University of Zurich

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Instead of just one antibody, the new technology allows 25 drug candidates to be tested simultaneously in a single mouse.

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Credit: Frank Brüderli, University of Zurich

New active ingredients such as antibodies are usually tested individually in laboratory animals. Researchers at UZH have now developed a technology that can be used to test around 25 antibodies simultaneously in a single mouse. This should not only speed up the research and development pipeline for new drugs, but also hugely reduce the number of laboratory animals required.

Many modern drugs are based on antibodies. These proteins very specifically identify a certain structure on the surface of cells or molecules and bind onto it – this may be a receptor protruding from the cell envelope. For antibodies and other protein-based biotherapeutics extensive preclinical tests need to be conducted on animals before they can be tested on humans.

Testing 25 antibodies simultaneously in one mouse

Currently, antibody candidates are analyzed individually in animal models. A large number of laboratory animals are normally used to conduct each test. This is why preclinical tests account for a large proportion of the animals used in the pharmaceutical industry. One possible solution would be to test several substances simultaneously in a single animal. However, up until now this method was restricted to a maximum of four active ingredients per animal.

Researchers at the University of Zurich (UZH) led by Markus Seeger from the Institute of Medical Microbiology and Johannes vom Berg from the Institute of Laboratory Animal Science have now managed to overcome this restriction. “The approach we developed allows us to test 25 different antibodies simultaneously in a single mouse. This speeds up the process and reduces the number of animals required,” says vom Berg. To conduct this study, the team used antibodies that are already approved as a drug or those undergoing clinical development.

Protein fragments as barcodes for analysis

Drugs need to have several properties to be successful: the active ingredient is only released slowly and can therefore develop its effect in the body for a prolonged period of time. It binds precisely to a specific target structure and accumulates in the corresponding organ. In addition, the substance only spreads to a limited extent in other tissues and organs, which reduces the risk of side effects.

To allow individual analysis of the properties of the antibodies from the complex plasma or tissues samples from the mice, the researchers developed a form of barcodes. They are made up of defined protein fragments – known as flycodes – that can be used to mark each antibody individually. Once they have been administered to the mouse, the individual antibody candidates can be separated from the mixture and analyzed separately. “Our results show that the flycode technology delivers high-quality preclinical data on the investigated antibodies. We get much more data with fewer mice and the data is of a better quality because the analyses can be compared directly,” says Seeger.

Great potential to reduce the numbers of laboratory animals

The researchers also demonstrated that the antibodies find their target structures correctly in the animals’ body: for example, two of the antibodies used in cancer medicine reliably identified the EGF receptor which the tumor cells primarily carry on the surface. The targeted accumulation in the tumor tissue also worked in a mixture with 20 other antibodies. This demonstrates that flycodes do not compromise the efficacy of the antibodies in a living organism.

In addition, the team used flycodes to analyze the properties and data for a series of 80 drug-like synthetic biomolecules – known as sybodies – efficiently in a single experiment. “Using minimal resources, the flycode technology allows a direct comparison of drug candidates under identical experimental conditions. It is set to advance preclinical discovery pipelines much more efficiently in the future,” says Markus Seeger. All the data in this study originates from just 18 mice. In principle, this new method can reduce the number of animals required by a factor of up to 100.

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Journal

Proceedings of the National Academy of Sciences

DOI

10.1073/pnas.2426481122 

Method of Research

Experimental study

Subject of Research

Animals

Article Title

Flycodes enable simultaneous preclinical analysis for dozens of antibodies in single cassette–dosed mice

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