Tag

Paleoclimatology

All articles tagged with #paleoclimatology

science4 days ago•50 min saved

New Mexico Footprints Reveal 2,000-Year Human Survival Amid Ice Age Climate Chaos

A new study published in Science Advances confirms that early humans in New Mexico lived through rapid, extreme climate shifts during the last ice age. By analyzing sediment layers at White Sands National Park, researchers found that people inhabited the area for nearly 2,000 years while the environment swung between wet and arid conditions. The findings suggest that human presence was not continuous but occurred in pulses, often coinciding with geological changes that preserved footprints.

via Yahoo|

#archaeology #human-migration #ice-age

science5 days ago•97 min saved

White Sands pollen reveals Indigenous ancestors endured rapid climate shifts 23,000 years ago

A new study published in *Science Advances* confirms that Indigenous ancestors in New Mexico lived through rapid, extreme climate changes during the Last Glacial Maximum. By analyzing ancient pollen and organic molecules in sediments at White Sands National Park, researchers determined that the landscape shifted from conifer forests to sagebrush steppe within a single human lifetime. This evidence supports the existence of humans in North America approximately 23,000 years ago, challenging previous assumptions that the continent was uninhabited until 13,000 years ago.

via Live Science|

#archaeology #indigenous-history #last-glacial-maximum

science6 days ago•123 min saved

Ancient Sea Levels Reveal Rapid Polar Shifts During Dinosaur Era

New analysis of ancient sea-level data indicates that Earth's geographic poles shifted rapidly during the Jurassic and Cretaceous periods, moving up to 0.6 degrees per million years. This 'true polar wander' occurred as the planet's crust and mantle reoriented relative to its spin axis to balance mass distribution, potentially altering global climate patterns and habitats for dinosaurs and early primates.

via Space|

#dinosaur-era #earth-science #geology

science-tech22 days ago•10 min saved

Giant Clam Shell Decodes 200-Year-Old Climate Diary of the Great Barrier Reef

Researchers reconstructed month-by-month climate conditions at the northern Great Barrier Reef 200 years ago by analyzing the shell of a giant clam (Tridacna gigas). The study, conducted in partnership with Aboriginal communities, reveals that pre-industrial summers were 0.9–1.2°C cooler than today, while winters remained similar. The shell’s geochemical layers provided a detailed record of temperature and rainfall variability, including El Niño and La Niña cycles, offering a rare high-resolution climate archive for the Southern Hemisphere.

via The Conversation|

#climate-science #great-barrier-reef #indigenous-partnership

science1 month ago•3 min saved

New Models Suggest Zancan Flood Refilled Mediterranean in Months, Not Years

Recent modeling of the Zancan flood, which refilled the Mediterranean Sea approximately 5.33 million years ago, estimates peak water flow through the Strait of Gibraltar at 100 million cubic meters per second. This volume is roughly 1,000 times the average discharge of the Amazon River. The event ended the Messinian Salinity Crisis, a period where the Mediterranean dried out and accumulated thick salt deposits. While the physical erosion of the seabed is measured, the specific flow rates are modeled estimates based on the shape of the carved channel.

via Space Daily|

#geology #hydrology #mediterranean

science2 months ago•4 min saved

Earth’s Chemical Shifts May Have Warned of Past Mass Extinctions

A new study in Nature Communications suggests that Earth’s chemical shifts served as early warning signs for the five largest mass extinctions. Researchers identified five distinct climate regimes over the past 539 million years, noting that transitions between these regimes coincided with peaks in biosphere vulnerability. While specific disasters like asteroid impacts caused the extinctions, these chemical wobbles indicated periods when life was more fragile and susceptible to catastrophic loss.

via ScienceAlert|

#biosphere-vulnerability #climate-change #geological-history

environment2 months ago•3 min saved

Fossil Evidence Shows Ancient Warming Caused Forest Collapse, Not Growth

A new study in Science reveals that during the Paleocene-Eocene Thermal Maximum (PETM) 56 million years ago, rapid carbon release led to a 60% loss of forest canopy, contradicting claims that high CO2 levels 'green' the planet. Researchers analyzed fossil leaf cuticles in Wyoming to reconstruct this ancient ecosystem collapse, which took over 100,000 years to recover. The findings warn that current human-driven warming, occurring 10 times faster than the PETM, may push modern forests past critical thresholds, leading to irreversible ecological damage.

via theguardian.com|

#carbon-emissions #climate-change #environment

science2 months ago•9 min saved

Toba eruption’s climate punch turned out to be modest and short-lived, study finds

New high-resolution lake records from Lake Chala near Kilimanjaro show Mount Toba's 74,000-year eruption cooled eastern Africa by about 0.5°C for roughly 18 months, a far milder regional impact than once imagined and not clearly indicating a global threat; researchers caution that conclusions come from a single site and more records are needed to assess worldwide effects.

via Ars Technica|

#climate-impact #lake-chala #paleoclimatology

science3 months ago•13 min saved

The Green Sahara’s 20,000-year rhythm: how orbital cycles once turned North Africa lush

Earth’s orbital precession creates a roughly 19,000–23,000-year cycle that can pull monsoons deep into North Africa, turning the Sahara into grasslands, wetlands and lakes and even hosting hippos and crocodiles. The last humid phase occurred in the Holocene (about 14,500–5,000 years ago) as a mosaic landscape, not a rainforest, ending gradually as conditions dried. Evidence comes from lake sediments, sapropels, river records and archaeology. Future green periods are not guaranteed and depend on multiple factors, including ice sheets, dust, sea temperatures and human warming—proving the Sahara is not permanently dry.

via Space Daily|

#green-sahara #holocene #orbital-precession

earth-science3 months ago•16 min saved

Ancient Ocean Heatwaves Hint at Today’s Warming Danger

A new study links the Permian-Triassic 'Great Dying' to warming oceans with expanding oxygen-poor waters, showing species most vulnerable to higher temperatures and low oxygen died off at higher rates; the findings serve as a warning that contemporary human-driven warming could trigger a similar marine crisis if carbon emissions aren’t curbed.

via Gizmodo|

#earth-science #global-warming #great-dying

science3 months ago•12 min saved

Mantle Waves Helped Antarctica Freeze Ahead of the Arctic

A new study argues that deep-Earth mantle waves, triggered during the Gondwana breakup, uplifted East Antarctica around 45 million years ago. This uplift raised elevations high enough for snow to persist, allowing the East Antarctic ice sheet to form by about 34–35 million years ago and contribute to global cooling. The Arctic, lacking similar high terrain, lagged behind by roughly 25 million years, with climate and CO2 declines later driving ice-age conditions. The work suggests geology helped set the stage for ice sheets long before climate alone made the poles cold.

via The Conversation|

#antarctica #geology #ice-sheets

science3 months ago•6 min saved

Could Distant Planetary Flybys Have Triggered Earth's Mass Extinctions?

A conference-backed hypothesis by Daniele Fargion suggests gravitational tides from flybys of planetary-mass bodies or outer Solar System dwarfs near Earth could have driven major extinctions by triggering huge tides, volcanism, climate shifts, and altered meteoritic delivery. Citing correlations with known extinctions (including the Permian/Triassic) and clues in the Earth–Moon system, the idea is speculative and not yet dated or widely validated, but it frames tidal encounters as a possible common cause alongside impacts and volcanism.

via Universe Today|

#mass-extinctions #outer-solar-system #paleoclimatology

science6 months ago•9 min saved

Ancient Coccoliths Reveal a Cooler Miocene North Atlantic Than Expected

A Nature Communications study applies clumped-isotope geochemistry to exceptionally well-preserved fossil coccoliths to reconstruct 16 million years of North Atlantic temperatures, finding temperatures about 9°C cooler than previous alkenone-based estimates and closer to climate model simulations, challenging the view of extreme Miocene warmth and highlighting the need to re-evaluate climate proxies.

via SciTechDaily|

#clumped-isotope-geochemistry #coccolithophores #miocene

science8 months ago•4 min saved

Ancient Ocean Hidden Under West Antarctica Revealed by Deep Ice Drill

A multinational team drilled beneath the West Antarctic Ice Sheet, reaching 523 meters of ice and 228 meters of ancient rock and sediment, and found marine organisms and shell fragments that indicate parts of the region were once open ocean. These findings shed light on past warmer climates over the last roughly 23 million years and could help improve predictions of future sea-level rise as the ice sheet retreat cycles are better understood.

via The Daily Galaxy|

#antarctica #climate-change #ice-sheet

science8 months ago•3 min saved

Deep Antarctic Drill Uncovers Ancient Open-Ocean Clues

Scientists drilled 523 meters through the Crary Ice Rise on the Ross Ice Shelf and recovered 228 meters of sediment, finding evidence that parts of West Antarctica were once open ocean as recently as about 23 million years ago. The findings help decode past ocean temperatures and environmental conditions to improve predictions of future ice loss and sea‑level rise; samples are being analyzed in New Zealand after transport from Antarctica.

via ScienceAlert|

#antarctica #ice-shelf #ocean-history