Curtin scientists freeze out ice-age delivery theory for Stonehenge stones

Dr Anthony Clarke at Stonehenge
Photo Credit: Courtesy of Curtin University

Scientific Frontline: "At a Glance" Summary

• Main Discovery: Recent geological analysis provides the strongest evidence to date that Stonehenge’s massive stones were transported by humans rather than glacial movement during the Ice Age, effectively debunking the long-standing "glacial transport theory."
• Methodology: Researchers conducted advanced geochemical "fingerprinting" and geochronological dating on over 500 microscopic zircon crystals extracted from river sands and sediments across the Salisbury Plain, specifically looking for foreign mineral signatures that glaciers would have deposited.
• Key Data: The analysis revealed a complete absence of distinct mineral grains from the known Scottish or Welsh source rocks in the local Salisbury sediment; had glaciers moved the stones, trace minerals matching the Altar Stone (Scotland) or bluestones (Wales) would be abundant in the surrounding terrain.
• Significance: This finding firmly establishes that the transport of the six-tonne Altar Stone over 750 kilometers and the bluestones over 200 kilometers was a deliberate feat of Neolithic engineering and societal organization, likely involving complex maritime or overland trade networks.
• Future Application: The isotopic and mineral dating techniques refined in this study will be applied to other ancient monuments and artifacts globally to trace their origins and uncover prehistoric movement patterns without damaging the objects.
• Branch of Science: Geology, Geochemistry, and Archaeology.
• Additional Detail: This study follows the team's 2024 discovery which pinpointed the Altar Stone’s origin to the Orcadian Basin in northeast Scotland, a distance previously thought impossible for manual transport in that era.

Microplastics in the atmosphere: higher emissions from land areas than from the ocean

Image Credit: Scientific Frontline / AI generated

Scientific Frontline: "At a Glance" Summary

• Main Discovery: Terrestrial sources emit over 20 times more microplastic particles into the atmosphere than oceanic sources, challenging previous assumptions that the ocean was the primary emitter.
• Methodology: Researchers collected 2,782 globally distributed atmospheric microplastic measurements and compared them against a transport model using three different emission estimates, subsequently rescaling the emission data to reconcile significant discrepancies between the model and observations.
• Key Data: While land areas emit >20 times more individual particles, the total emitted mass is actually higher over the ocean due to the significantly larger average size of oceanic particles.
• Significance: This study provides the first rescaled, observation-based estimate of global microplastic emissions, revealing that current models had overestimated atmospheric microplastic concentrations and deposition rates by several orders of magnitude.
• Future Application: These improved emission estimates will refine global pollution transport models and help isolate specific contributions from sources like road traffic (tyre abrasion) versus other land-based activities.
• Branch of Science: Meteorology and Geophysics.
• Additional Detail: Primary terrestrial sources were identified as tyre abrasion, textile fibers, and the resuspension of already contaminated dust and soil.

Study Finds Ocean Impacts Nearly Double Economic Cost of Climate Change

A mangrove in Laguna del Cacahuate, Tabasco, Mexico.
Photo Credit: Octavio Aburto

Scientific Frontline: "At a Glance" Summary

• Main Discovery: Integrating ocean-related damages into the social cost of carbon calculation nearly doubles the estimated global economic harm caused by carbon dioxide emissions.
• Methodology: Researchers developed a framework accounting for market use values (fisheries, trade), non-market values (health, recreation), and non-use values (biodiversity existence), then integrated these into an economic model calibrated to various greenhouse gas emission trajectories.
• Key Data: The social cost of carbon increases from $51 to $97.2 per ton—a 91% rise—with market damages alone projected to reach $1.66 trillion globally per year by 2100.
• Significance: This "blue" social cost of carbon assigns monetary values to previously overlooked ocean variables like coral reef degradation and coastal infrastructure damage, preventing these factors from being invisible in standard economic accounting.
• Future Application: Policymakers and private sector leaders can utilize this metric to refine cost-benefit analyses for environmental regulations, risk management strategies, and corporate emission damage assessments.
• Branch of Science: Environmental Economics and Oceanography
• Additional Detail: The study highlights a highly unequal distribution of economic impact, with islands and small economies facing disproportionate harm due to their reliance on seafood and vulnerability to sea-level rise.

How climate change contributed to the demise of the Tang dynasty

Climatic and sociocultural changes may have contributed significantly to the demise of the Tang dynasty by weakening border defenses.
Image Credit: Scientific Frontline

Scientific Frontline: "At a Glance" Summary

• Main Discovery: Hydroclimatic instability, characterized by extreme droughts and floods between 800 and 907 CE, functioned as a critical driver in the socio-political collapse of the Tang Dynasty.
• Methodology: Researchers reconstructed historical runoff behavior in the Yellow River basin by analyzing long-term tree-ring data archives to model local hydroclimatic trends during the 9th century.
• Specific Mechanism: Vulnerability to climate extremes was exacerbated by an agricultural shift from drought-resistant millet to water-intensive wheat and rice, resulting in uncompensated crop failures during dry periods.
• Systemic Consequences: Compounded by collapsed supply corridors, widespread malnutrition weakened northern border defenses and precipitated mass migration southward, destabilizing the empire's political structure.
• Significance: The study establishes a historical precedent for how environmental stressors, when intersecting with specific socio-cultural choices, can trigger irreversible tipping points in complex societal systems.

How hidden factors beneath Istanbul shape earthquake risk

Istanbul
Photo Credit: Ozgu Ozden

Scientific Frontline: "At a Glance" Summary

• Main Discovery: New research reveals that underground temperature variations and sediment thickness segment the Main Marmara Fault, preventing a single catastrophic rupture of the entire fault line and instead causing it to break in discrete sections.
• Methodology: Scientists employed physics-based simulations modeling over 10,000 years of seismic activity, integrating specific rock rheology (deformation properties) and fault geometry to accurately reproduce historical earthquake patterns, such as those from 1766 and 1912.
• Key Statistic: The models predict a maximum earthquake magnitude of approximately 7.3, with western fault segments producing magnitude 7.2 events roughly every 150 years and eastern segments generating magnitude 6.2–6.8 "doublets" every 100 years.
• Mechanism: The study identified that sedimentary rocks deform stably at shallow depths (creeping) while high temperatures at greater depths weaken rocks, effectively creating physical barriers that stop ruptures from expanding into massive megathrust events.
• Significance: These findings challenge previous assumptions of a single "Big One" event, indicating that while locked segments pose an imminent threat after over a century of silence, the seismic hazard is physically constrained by these geological factors.

‘Cosmic clock’ reveals Australian landscapes’ history and potential future

Scanning electron microscope image of zircon crystals. Each crystal is about 0.1 millimeters in size, which is roughly the thickness of a human hair, and records cosmogenic krypton as a geochemical time archive.
Photo Credit: Maximilian Dröllner

Scientific Frontline: "At a Glance" Summary

• Main Discovery: A new geochronological method utilizing cosmogenic krypton isotopes trapped in zircon crystals has been established to reconstruct the erosion and exposure history of ancient Australian landscapes.
• Methodology: Researchers analyzed krypton gas generated by cosmic ray interactions with zircon grains to quantify the duration these minerals spent near Earth's surface prior to burial, effectively functioning as a "cosmic clock."
• Geological Insight: The data indicates that during periods of tectonic stability and high sea levels, erosion rates slow dramatically, causing sediments to be stored and reworked near the surface for millions of years.
• Resource Formation: This prolonged surface exposure facilitates the weathering of unstable materials while concentrating durable minerals, explaining the geological origin of Australia's extensive mineral sand deposits.
• Significance: The findings provide a long-term perspective on how landscapes respond to deep-seated tectonic and climatic forces, offering critical data to improve predictive models for future land management and sediment system changes.

What Is: Nuclear Winter

A Planetary System Collapse
Image Credit: Scientific Frontline

Scientific Frontline: Extended"At a Glance" Summary

The Core Concept: A severe, prolonged, and global climatic cooling effect hypothesized to occur following widespread urban firestorms ignited by a large-scale nuclear exchange. It represents a fundamental decoupling of the Earth’s climate from its current stable equilibrium, resulting in sub-freezing terrestrial temperatures and precipitation collapse.

Key Distinction/Mechanism: Unlike the immediate, localized destruction of blast waves and radiation, nuclear winter is a planetary-scale environmental catastrophe. The primary mechanism is the injection of millions of tons of black carbon soot into the stratosphere via "pyrocumulonimbus" (fire-driven storm) clouds; this soot intercepts solar radiation, heating the upper atmosphere while plunging the surface into darkness and cold.

Origin/History: The term was coined in the early 1980s (notably associated with the TTAPS studies) and has been rigorously re-examined in the 2020s, culminating in a landmark 2025 consensus study by the National Academies of Sciences, Engineering, and Medicine (NASEM).

Major Frameworks/Components:

• Urban Fuel Loading: Modern cities act as dense reservoirs of combustible mass (plastics, hydrocarbons), capable of fueling firestorms with higher soot yields than mid-20th-century targets.
• Self-Lofting Microphysics: Black carbon particles absorb sunlight and heat the surrounding air, causing the soot plume to rise deeper into the stratosphere (40–50 km) where it persists for years.
• The "Nuclear Niño": A feedback loop where unequal cooling between land and oceans disrupts the Walker Circulation, triggering a seven-year El Niño-like state that collapses marine ecosystems.
• Hydrological Collapse: The stabilization of the atmosphere and reduction in surface evaporation could reduce global precipitation by 40% to 50%, causing a "cold drought."
• "UV Spring": As the soot clears, a severely depleted ozone layer (destroyed by stratospheric heating and nitrogen oxides) exposes the surface to dangerous levels of UV-B radiation.

Why It Matters: Nuclear winter is identified as the primary mechanism of destruction in a nuclear conflict, potentially killing up to 5 billion people through starvation rather than blast effects. It triggers a "system of systems" failure—collapsing agriculture, energy grids, and global trade—that creates an "energy trap" from which civilization may not be able to recover.

Cosmogenic krypton enables reconstruction of landscapes millions of years old

Noble gas laboratory in Cologne where the krypton was analyzed for the study.
Photo Credit: © Dr Tibor Dunai

Scientific Frontline: "At a Glance" Summary

• Geochemical Innovation: Researchers have developed a novel method to reconstruct landscape evolution from tens of millions of years ago by analyzing cosmogenic krypton isotopes trapped within zircon minerals.
• Methodological Framework: The approach integrates measurements of stable cosmogenic krypton—produced by cosmic radiation hitting surface minerals—with traditional U-Pb dating to distinguish between the time of mineral formation and the duration of surface exposure.
• Sediment Residence Times: Analysis of drill cores from Australia's Eucla Basin revealed that some zircon grains remained on the Earth’s surface for over one million years before final deposition.
• Paleoclimate Correlation: Data identifies a transition in the middle Eocene from long-stored, weathered sediments to more dynamic transport systems, a shift that aligns with documented fluctuations in sea levels and tectonic activity.
• Extended Temporal Range: Unlike established cosmogenic nuclides with short half-lives that limit dating to recent geological history, the stability of cosmogenic krypton allows for the quantitative tracking of sediment transport and storage over tens of millions of years.
• Future Application: The technique provides a primary tool for quantifying the landscape history of tectonically stable continents and assessing how ancient climate changes influenced long-term Earth surface dynamics.

Hygienic conditions in Pompeii’s early baths were poor

Pools of the oldest public bathing facilities in Pompeii, dating back to 130 BC
Photo Credit:© Cees Passchier

Scientific Frontline: "At a Glance" Summary

• Main Discovery: Isotope analysis of carbonate deposits reveals that Pompeii’s early "Republican Baths" (c. 130 BC) maintained poor hygienic conditions, relying on stagnant, highly mineralized well water rather than fresh aqueduct supplies.
• Methodology: Researchers reconstructed the ancient water supply by analyzing stable isotopes and trace elements in limescale (calcium carbonate) samples collected from the city’s wells, water towers, and bath pools.
• Key Data: Anthropogenic deposits contained distinct peaks of lead, zinc, and copper, indicating significant heavy metal contamination caused by the corrosion of the facility's boilers and pipes.
• Mechanism: Prior to the Augustan aqueduct, water was extracted via slave-powered treadwheels; this labor-intensive process limited water renewal to roughly once per day, failing to flush contaminants effectively.
• Significance: The findings challenge the historical assumption of uniformly high Roman hygiene, demonstrating that superior sanitation standards were only achievable after the introduction of high-volume aqueduct infrastructure.
• Volcanic Insight: Cyclic patterns observed in the carbon isotopes of well deposits suggest fluctuating volcanic CO₂ levels, potentially serving as a paleo-record of Mount Vesuvius's activity prior to the AD 79 eruption.

Sediments of the Ahr river show recurring high-magnitude flood events

The extreme summer flood of 2021 in the Ahr Valley caused catastrophic damage.   
Photo Credit: Physical Geography working group, Leipzig University

Sedimentary archives provide evidence of four extreme flood events in the last 1,500 years 

Recurring high-energy flood events are not the exception but the rule in the Ahr Valley in western Germany – and this occurs over periods of centuries to millennia. This is shown in a study published in the journal Earth Surface Processes and Landforms and led by Leipzig University, in which researchers from the Helmholtz Centre for Environmental Research (UFZ), among others, were also involved. The examined river sediments document the extreme summer flood of 2021 as well as at least three other flood events in the past 1,500 years, which – measured by sedimentological parameters – exhibited comparable intensity. The Ahr floodplain is characterized by high-energy flood deposits. Flood events of low to moderate intensity are not detectable there. 

Ancient Antarctica reveals a ’one–two punch’ behind ice sheet collapse

An image of Antarctica as seen from space.
Image Credit: NASA.

When we think of global warming, what first comes to mind is the air: crushing heatwaves that are felt rather than seen, except through the haziness of humid air. But when it comes to melting ice sheets, rising ocean temperatures may play more of a role — with the worst effects experienced on the other side of the globe.

While Binghamton University Associate Professor of Earth Sciences Molly Patterson is the first author, the 43 co-authors include several Binghamton alumni, such as Christiana Rosenberg, MS ’20; Harold Jones ’18; and William Arnuk, PhD ’24. The study’s results directly address one of the main goals of the International Ocean Drilling Program (IODP) Expedition 374: to identify the sensitivity of the Antarctic ice sheet to Earth’s orbital configuration under a variety of climate boundary conditions. Because of this, all shipboard science team members are included as co-authors because of their contributions to the data sets used in the article, Patterson explained.

New research may help scientists predict when a humid heat wave will break

Caption:MIT scientists have identified a key atmospheric condition that determines how hot and humid midlatitude regions like the Midwest can become — and how intense related storms may be.
Image Credit: Scientific Frontline / stock image

A long stretch of humid heat followed by intense thunderstorms is a weather pattern historically seen mostly in and around the tropics. But climate change is making humid heat waves and extreme storms more common in traditionally temperate midlatitude regions such as the midwestern U.S., which has seen episodes of unusually high heat and humidity in recent summers.

Now, MIT scientists have identified a key condition in the atmosphere that determines how hot and humid a midlatitude region can get, and how intense related storms can become. The results may help climate scientists gauge a region’s risk for humid heat waves and extreme storms as the world continues to warm.

In a study appearing this week in the journal Science Advances, the MIT team reports that a region’s maximum humid heat and storm intensity are limited by the strength of an “atmospheric inversion”— a weather condition in which a layer of warm air settles over cooler air.

Scientists discover what drives California's worst fire years

Two natural resource specialists walk through an area of Redwood Mountain Grove burned in the KNP Complex Fire in California’s Sierra Nevada Mountains to evaluate fire effects.
Photo Credit: National Park Service

What makes one fire season worse than another in fire-prone parts of the world like California is poorly understood, but in a new study, scientists at the University of California, Irvine reveal how clusters of lightning-ignited fires called fire complexes are the chief drivers of the most destructive fire years. It’s a finding that could help agencies better manage such fires when they occur.

“Nobody has ever looked into these kinds of fires before,” said Rebecca Scholten, a postdoctoral fellow in Earth system science and lead author of the Science Advances study. “We theorized that when two or more fires in a fire complex merge, they would just burn themselves out. But we found the opposite – the fires grow worse.”

What Is: The Anthropocene

Image Credit: Scientific Frontline / stock image

At a Glance

• The Core Concept: The Anthropocene, or "Age of Man," is a proposed geological epoch positing that human activity has superseded natural forces to become the primary driver of Earth's geological and ecological systems.
• Key Distinction/Mechanism: Unlike the Holocene—the stable epoch of the last 11,700 years that fostered human civilization—the Anthropocene represents a fundamental rupture in Earth's history where humanity operates as a geological force rather than merely a biological one. It is characterized by the human-driven alteration of the atmosphere, hydrosphere, cryosphere, and biosphere, shifting the planet into a volatile and unstable interval.
• Origin/History: The term was popularized by atmospheric chemist Paul Crutzen at the turn of the millennium (c. 2000) to describe the profound impact of humanity on the planet.

Major Frameworks/Components

• A Diachronous "Event": The scientific community increasingly views the Anthropocene not strictly as a defined epoch with a singular start date (a "golden spike"), but as an unfolding, diachronous geological event comparable to the Great Oxidation Event.
• Planetary Health Indicators: The framework highlights critical shifts such as the disruption of nitrogen and phosphorus cycles, rapid ocean acidification, and accelerating species extinction.
• Stratigraphic Alteration: The concept suggests that humanity has fundamentally altered the physical stratigraphic record of the Earth.
• Why It Matters: The Anthropocene redefines the current environmental crisis not as a series of isolated issues, but as a systemic transformation of the Earth caused by a single species. It serves as the dominant conceptual framework for understanding planetary instability and signals that the conditions necessary for known civilization are ending.

Water’s Age and What It Can Tell Us

PhD student Joshua Snarski is using stable water isotopes to study how water is stored and released from soil in agricultural settings.
Photo Credit: Courtesy of University of Connecticut

When it rains, what happens to the water once it enters the soil? Does the new precipitation mix with all of the water that was already there? In their recent paper in Water Resources Research, Department of Natural Resources and the Environment Ph.D. student Joshua Snarski and assistant professor James Knighton show the answer is more complicated than previously assumed, but knowing the age of water gives a more accurate picture.

Hydrologists use models to simulate what is happening in natural systems. Since hydrologic processes are complex, researchers need to make assumptions about some aspects, such as how water mixes within the soil profile. Though previous hydrologic research is focused on the amount and timing of precipitation, Snarski says shifting the focus to the age of water within the soil profile can reveal more about what is happening beneath the surface.

Scientists Crack Ancient Salt Crystals to Unlock Secrets of 1.4 Billion-Year-Old Air

Microscopic image of fluid inclusions in 1.4-billion-year-old halite crystals, which preserve ancient air and brine.
Image Credit: Justin Park/RPI

More than a billion years ago, in a shallow basin across what is now northern Ontario, a subtropical lake much like modern-day Death Valley evaporated under the sun’s gentle heat, leaving behind crystals of halite — rock salt.

It was a very different world than the one we know today. Bacteria were the dominant form of life. Red algae had only just appeared on the evolutionary scene. Complex multicellular life like animals and plants wouldn’t show up for another 800 million years. 

As the water evaporated into brine, some of it became trapped in tiny pockets within the crystals, effectively frozen in time. Those trapped fluid inclusions contained air bubbles revealing, in fine detail, the composition of the early Earth’s atmosphere. The crystals were buried in sediment, effectively sealed off from the rest of the world for 1.4 billion years, their secrets unknown. Until now. 

Ultra-high-resolution Lidar Reveals Hidden Cloud Structures

This experimental setup at Michigan Technological University allows researchers to create and study clouds under carefully controlled conditions. Researchers from Brookhaven National Laboratory used it to demonstrate the capabilities of a new ultra-high-resolution lidar, a laser-based remote sensing instrument for studying cloud properties.
Photo Credit: Michigan Technological University

Scientists at the U.S. Department of Energy’s (DOE) Brookhaven National Laboratory and collaborators have developed a new type of lidar — a laser-based remote-sensing instrument — that can observe cloud structures at the scale of a single centimeter. The scientists used this high-resolution lidar to directly observe fine cloud structures in the uppermost portion of laboratory-generated clouds. This capability for studying cloud tops with resolution that is 100 to 1,000 times higher than traditional atmospheric science lidars enables pairing with measurements in well-controlled chamber experiments in a way that has not been possible before.

The results, published in the Proceedings of the National Academy of Sciences, provide some of the first experimental data showing of how cloud droplet properties near the tops of clouds differ from those in the cloud interior. These differences are crucial to understanding how clouds evolve, form precipitation, and affect Earth’s energy balance.

“This is the first time we’ve been able to see these cloud-top microstructures directly and non-invasively,” said Fan Yang, an atmospheric scientist at Brookhaven Lab and the lead author of the study. “These structures occur on scales smaller than those used in most atmospheric models, yet they can strongly affect cloud brightness and how likely clouds are to produce rain.”

What Is: The Phanerozoic Eon

Defining the Eon of Complex Life
Image Credit: Scientific Frontline / AI generated

The Phanerozoic Eon constitutes the current and most biologically dynamic division of the geological time scale. Spanning the interval from approximately 538.8 million years ago (Ma) to the present day, it represents roughly the last 12% of Earth's 4.54-billion-year history. Despite its relatively short duration compared to the preceding Precambrian supereon—which encompasses the Hadean, Archean, and Proterozoic eons—the Phanerozoic contains the overwhelming majority of the known fossil record and the entirety of the history of complex, macroscopic animal life.  

Storms in the Southern Ocean mitigates global warming

Visible satellite image showing storms sweeping across the Southern Ocean on 4 January 2019.
Photo Credit: NASA Worldview Snapshot

Intense storms that sweep over the Southern Ocean enable the ocean to absorb more heat from the atmosphere. New research from the University of Gothenburg shows that today’s climate models underestimate how storms mix the ocean and thereby give less reliable future projections of our climate. 

The Southern Ocean is a vast expanse of ocean encircling the Antarctic continent, regulating Earth’s climate by moving heat, carbon, and nutrients out in the world’s oceans. 

It provides a critical climate service by absorbing over 75 per cent of the excess heat generated by humans globally. The Southern Ocean’s capacity to reduce climate warming depends on how efficiently it can absorb heat from our atmosphere.  

Farmers boosted Europe's biodiversity over the last 12,000 years

Standing stones in Carnac, France. Built between 6,500 - 5,300 years ago by Europe's first farmers.
 Photo Credit: Jonny Gordon.

Although humans are to blame for nature’s recent decline, a new study shows that for millennia, European farming practices drove biodiversity gains, not losses. 

Standing stones in Carnac, France. Built between 6,500 - 5,300 years ago by Europe's first farmers. Picture by Jonny Gordon. 

A team of researchers at the University of York analyzed fossil pollen records from Europe to track vegetation changes stretching back 12,000 years. They discovered that as new populations of farmers from Turkey moved into Europe 9,000 years ago, far from destroying plant diversity, they enriched it. 

Dr Jonny Gordon is a Postdoctoral Research Associate in the Leverhulme Centre for Anthropocene Biodiversity and lead author of the new paper, Increased Holocene diversity in Europe linked to human-associated vegetation change, which has been published in Global Ecology and Biogeography.