Solar-Driven Atmospheric Dynamics in Neoglacial Evolution
In a recent article, I introduced the idea that the transition from the thermal maximum of the Holocene Interglacial that defined the Northgrippian sub-epoch, to the on-set of present Meghalayan (neoglacial) sub-epoch, some 4,200 years ago, was found to coincide with both a sudden multi-centennial increase in iceberg calving rates into the North Atlantic and with an increase in the environmental concentrations of beryllium‑10 (10Be) and carbon‑14 (¹⁴C) isotopes
These isotopes are said to be cosmically generated (aka cosmogenic isotopes) and thus they provide a window into past solar – terrestrial interactions.
Here in this article, I will expand on this theme and introduce a framework of ideas that I believe help explain why the Last Glacial Maximum (LGM) was defined by the extreme lack of coherence in glacial ice (cover image) extending along the extra-tropical Northern Hemisphere latitudes.
The literature that I will emphasize in this review, shows that solar weather (activity) has a profound influence on higher latitude atmospheric circulation and precipitation patterns.
As this is a long and in-depth story, I wanted to provide a shortened teaser that summarizes what you will discover with me, as I have attempted to produce a hypothesis on the how this mechanism unfolds.
Abstract
The conventional Milankovitch paradigm explains late-Holocene cooling after the Holocene Thermal Maximum (HTM) chiefly through declining high-latitude summer insolation due to reduced Earth obliquity, fostering gradual global cooling and lower atmospheric CO2 as oceans enhance carbon uptake.
Yet this model inadequately accounts for the pronounced hemispheric asymmetry in ice sheet distribution during the Last Glacial Maximum (LGM), with extensive Laurentide and Fennoscandian ice sheets along North Atlantic margins contrasted with an expansive ice-free Beringian corridor from the Urals to the Mackenzie Valley.
Nor does it explain the episodic, irregular iceberg-rafted debris (IRD) pulses in North Atlantic sediments since the Meghalayan neoglacial onset ~4.2 ka BP, which strongly correlate with elevated cosmogenic isotope (¹⁰Be, ¹⁴C) concentrations.
This synthesis argues that solar activity variations, modulating atmospheric dynamics atop the Milankovitch backdrop, ultimately generates a persistent glacial-atmospheric dipole responsible for these patterns achieved at the LGM.
Low solar output diminishes stratospheric ozone via reduced UV/EUV flux and alters energetic particle precipitation, weakening the stratospheric polar vortex and favoring negative Arctic Oscillation/North Atlantic Oscillation (AO/NAO) regimes.
Resulting meridional, wavy jet streams promote cold-air advection, enhanced storm tracks, and snowfall over Atlantic-sector continents while inducing high-pressure ridging, subsidence, and suppressed precipitation over Beringia, explaining its aridity despite cold conditions.
Paleoclimate proxies substantiate this through Bond Events: ~1,000–1,500-year cooling stadials featuring IRD surges, cosmogenic isotope peaks, meridional circulation shifts, and thermohaline deceleration, even within the HTM.
Inversely, Bond Optimals, which are warm intervals like the Minoan, Roman, Medieval, and Current Warm Periods, coincide with high solar activity, low cosmogenic isotope levels, zonal westerlies, reduced IRD, and glacial retreat, as evidenced by Gulf Stream intensification and ecological proxies.
Supporting mechanisms draw from heliospheric shielding of galactic cosmic rays, spallation-produced isotopes as solar proxies, and modeling (e.g., Shindell et al., 2001) linking Maunder Minimum forcing to amplified regional cooling via top-down stratospheric-tropospheric coupling.
Modern analogs confirm daily-to-decadal solar-geomagnetic influences on AO/NAO.
As ice sheets mature, internal feedbacks (e.g., albedo, topography, wave amplification) lock in the dipole, shifting dominance from external solar forcing in the neoglacial phase to internal oscillations toward the next glacial maximum.
Importantly, Earth’s current neoglacial state retains heightened solar sensitivity, framing the Current Warm Period as a Bond Optimum mirroring the Medieval Warm Period, flanking Bond Event 0 (Little Ice Age).
This is taken from a very long document, far more than we could accomodate here.
See the rest here substack.com
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