Deep ocean clues to a million-year-old Ice Age puzzle revealed in new study – Woods Hole Oceanographic Institution
Like almost all of Earth's history, a sudden change in the cyclic pattern of climate change occurred in that long, pre-Creation period. To be precise, 700,000 to 1 million years ago the pattern of glaciation and interglacial warm spells changed from a 41,000 year cycle, due to changes in the degree of tilt in Earth's rotation (axial precession), to one of about 100,000 years with no obvious change in axial precession or external causes such as solar radiation. This is known to climatologists and geologists as the Mid-Pleistocene Transition (MPT)
Given the conviction of creationists that their putative designer god created Earth perfectly tuned for them to live on, it will probably be disturbing to learn that Earth's pattern of climate can change radically over the long term, and not caused by anthropogenic increases in greenhouse gases but by perfectly natural processes that don't need the interference of a magic deity to explain them. On top of this all happening before they believe Earth was created out of nothing as a small flat planet with a dome over it, there is much here for creationists to ignore and for their cult to lie about.
What was the 'Mid-Pleistocene Transition'? The Mid-Pleistocene Transition (MPT) was a major shift in Earth's glacial-interglacial cycle patterns that occurred roughly 1.2 million to 700,000 years ago. Before the MPT, Earth's climate experienced shorter, 41,000-year cycles of glaciation and deglaciation, driven primarily by changes in the tilt of Earth’s axis. However, after the MPT, the cycles lengthened to about 100,000 years, with longer and more intense ice ages and warmer interglacial periods.The assumption has been that the MPT was caused by something to do with Earth's internal system dynamics, such as ocean currents, atmospheric CO2 levels and changes in polar ice sheets.
This transition has puzzled scientists because there wasn’t an obvious change in the external forces driving Earth’s climate (like solar radiation patterns). Instead, the MPT seems to be connected to internal Earth-system feedbacks, such as changes in ocean circulation, greenhouse gas levels, or ice sheet dynamics, that altered the planet's sensitivity to existing climate drivers.
Studying the MPT helps researchers understand how shifts in ocean temperatures, salinity, and circulation influenced climate. By analysing the chemical composition of foraminifera fossils, scientists aim to uncover the deep ocean's role in modulating these longer glacial cycles and to identify the feedback mechanisms that triggered this transition.
How does studying carbon, oxygen and isotopes of neodymium in foraminifera fossils reveal those details?
- Carbon and Oxygen Isotopes:
- Carbon Isotopes: Carbon in foraminifera reflects the balance between organic carbon and dissolved carbon in the ocean when they were alive. This ratio can indicate past levels of biological productivity and CO₂ levels in seawater, which are connected to atmospheric CO₂ and global temperatures.
- Oxygen Isotopes: Oxygen isotopes (specifically, oxygen-18 and oxygen-16) in foraminifera shells provide a record of past ocean temperatures and ice volumes. Higher levels of oxygen-18 generally indicate colder periods with more ice, as oxygen-16 evaporates more easily and becomes trapped in ice sheets, leaving relatively more oxygen-18 in the ocean. This helps reconstruct the temperature and ice volume of oceans during the foraminifera’s lifetime.
- Neodymium Isotopes:
- Neodymium isotopes are used as a "water mass tracer" because they vary depending on the geological sources of the water. Different regions have distinct neodymium isotope signatures, so by analysing these isotopes in fossilized shells, scientists can determine the origin of ocean water masses and track their movement over time. This reveals the "mixing history" of ocean waters from the northern and southern hemispheres, helping to trace the patterns of deep ocean circulation.
Together, these chemical clues in foraminifera fossils help reconstruct historical ocean temperatures, salinity (salt concentration), and circulation patterns. This is important for understanding how the oceans responded to climate changes in the past, which in turn can inform predictions about how they might respond to current climate shifts.
Now an international team of researchers from the Woods Hole Oceanographic Institution (WHOI), the Lamont-Doherty Earth Observatory, the Scripps Institution of Oceanography, and Cardiff University, have analysed the oxygen, carbon and isotopes of neodymium in the fossilised bodies of single-celled foraminifers in deep ocean sediment core samples and, reconstructed the changes on ocean currents, water temperature ocean salinity and atmospheric CO2. This has shown that the Southern Ocean played a vital part in the MPT.
The team have recently published their findings in Science and explained them in a press release from the Woods Hole Oceanographic Institute:
Deep ocean clues to a million-year-old Ice Age puzzle revealed in new study
Woods Hole, Mass. (Nov. 8, 2025) - A recently published study in Science challenges theories regarding the origins of a significant transition through the Earth’s ice ages. Led by an international team of researchers from the Woods Hole Oceanographic Institution (WHOI), the Lamont-Doherty Earth Observatory, the Scripps Institution of Oceanography, and Cardiff University, this research provides fresh insights into the ocean’s role in climate during the Mid-Pleistocene Transition, an enigmatic interval of change in climate cycles that began about one million years ago.
Many theories have been proposed for the Mid-Pleistocene Transition, and an important one is linked to a significant weakening of the Atlantic Meridional Overturning Circulation (AMOC). However, the new findings suggest an equally important but much more nuanced role for the deep ocean.
Using climate records spanning the past 1.2 million years, the team reconstructed deep ocean properties that are crucial for understanding the ocean’s flow and carbon sequestration capabilities.
The deep ocean is enormous, especially when considering its capacity to store carbon dioxide (CO2) compared to the atmosphere. Even a modest change in ocean circulation could significantly impact global climate.
Dr. Sophie K. V. Hines, lead author.
Department of Marine Chemistry & Geochemistry
Woods Hole Oceanographic Institution
Woods Hole, MA, USA.
The researchers analysed sediment core samples collected during the International Ocean Discovery Program (IODP) Expedition 361 near Cape Town, South Africa. By studying carbon and oxygen from fossils of single-celled organisms called foraminifera and isotopes of neodymium, the team uncovered details about the changes in deep ocean temperature and salinity, as well as the mixing histories of waters originating in both the northern and southern hemispheres.
Crucially, we show that shifts in different deep ocean properties are not always coincident. With our more highly resolved multi-proxy record that includes transitional intervals, we find that ice age intensification was influenced primarily by changes around Antarctica.
Professor Dr. Sidney R. Hemming, co-author.
Arthur D. Storke Memorial Professor of Earth and Environmental Sciences
Lamont-Doherty Earth Observatory
Columbia University, Palisades, NY, USA.
It is suggested that as the Antarctic Ice Sheet expanded, it enhanced the ocean's capacity to store carbon, leading to lower atmospheric CO2 levels, colder climates, and prolonged ice age cycles.
Our research sheds light on the intricate interplay between ocean dynamics and climate change, underscoring the significance of the Southern Ocean in understanding our planet's climate history.
Dr. Sophie K. V. Hines.
Recent studies stress the urgency of anthropogenic climate change, particularly in relation to reductions in the AMOC. As the Southern Ocean continues to warm at an alarming rate, understanding its dynamics is critical. The Southern Ocean plays a pivotal role in regulating global climate patterns, and its changes could have significant implications for ecosystems and weather systems worldwide.
So, creationists, was God just correcting his earlier mistake to make Earth more suitable for humans a million years before he magicked Earth out of nothing, having made one earlier that wasn't good enough?Abstract
The mid-Pleistocene transition (MPT) [~1.25 to 0.85 million years ago (Ma)] marks a shift in the character of glacial-interglacial climate (1, 2). One prevailing hypothesis for the origin of the MPT is that glacial deep ocean circulation fundamentally changed, marked by a circulation “crisis” at ~0.90 Ma (marine isotope stages 24 to 22) (3). Using high-resolution paired neodymium, carbon, and oxygen isotope data from the South Atlantic Ocean (Cape Basin) across the MPT, we find no evidence of a substantial change in deep ocean circulation. Before and during the early MPT (~1.30 to 1.12 Ma), the glacial deep ocean variability closely resembled that of the most recent glacial cycle. The carbon storage facilitated by developing deep ocean stratification across the MPT required only modest circulation adjustments.
Or does the scientific evidence of an old Earth running on natural laws, to which human life has adapted through evolution make more sense than the Bronze Age mythology of ignorant pastoralist?
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