Abrupt climate change also occurred naturally in the past
The following video from the “Klimaschau” series (No. 256), published by the European Institute for Climate and Energy (EIKE), addresses the question of whether abrupt climate changes in the past were natural or man-made.
Image cropped here.
The claim of an unprecedented speed of climate change is one of the arguments from alarmists in science and journalism that has only emerged in recent years.
Proponents claim that the emission of carbon dioxide by European industry has caused the average global temperature to change more rapidly since 1850 than ever before.
But is that true?
Published studies show that science has long been aware of significantly more extreme and rapid temperature shifts throughout Earth’s history.
Researchers have been investigating rapid temperature changes in Earth’s climate. One prominent example of this is a study titled “Global atmospheric teleconnections during Dansgaard-Oeschger events” by a working group led by Bradley Markle from Seattle University in Washington State, published in 2017 in the journal Nature Geoscience.
During the last ice age (approx. 110,000 to 12,000 years ago), there were at least 25 events where temperatures over Greenland rose by up to 16.5°C within just a few decades. These fluctuations were not local phenomena. Researchers like Bradley Markel from Seattle University demonstrated that these events had global impacts, such as the shifting of tropical rain belts or the “bipolar seesaw” effect (where warming in the North coincided with cooling in the South).
The 2017 study proves that the atmosphere reacted to changes in the North Atlantic within a few decades. Storm tracks shifted simultaneously with northern temperature jumps—well before the oceans showed a response.
The EIKE video even references research by climate alarmist Stefan Rahmstorf (PIK) from 2003, which suggested these events occurred in a regular cycle of approximately 1,470 years. At the time, Rahmstorf hypothesized an origin outside the Earth’s system (e.g., solar influences) due to the high precision of the timing.
These earlier findings clash with Rahmstorf’s more recent statements from 2022, where he claims modern warming is ten times faster than natural warming during the transition from the Ice Age to the Holocene.
Summary
The Earth’s history has already experienced massive and extremely rapid climate shifts that were entirely natural in origin.
[…] Abrupt Climate Change Also Occurred NATURALLY In The Past …25 Times During Last Ice Age […]
[…] ago, during the last glacial period, scientists documented at least 25 abrupt warming events.[1][2] Known as Dansgaard-Oeschger events, these shifts demonstrated nature’s capacity for rapid […]
I live in Washington State and have never heard of Bradley Markle from Seattle University. I wonder why this report wasn’t newsworthy? He seems to be at the Univ. of Colorado at Boulder.
More to the point who got at Rahmstorf? Follow the money! PIK – fraud.
Climate of the past.
https://www.bbc.co.uk/news/articles/c8ejjw7377jo
“Huge hidden cave under castle with prehistoric hippo bones ‘once in a lifetime’ find”
Presumably the last inter-glacial. From copilot search “Hippopotamuses primarily inhabit tropical savannah climates in sub-Saharan Africa, where they thrive in warm, wet environments with distinct wet and dry seasons.”
Recent Paleo evidence that could rock science.
A testable hypothesis proposing that the Maya warming period, the Medieval Warm Period, and the documented warming across North America from ~250–1350 CE represent connected phases of a contiguous, hemispheric-to-global warming event; the hypothesis should specify mechanisms, spatiotemporal structure, proxy expectations, and falsifiable predictions.
Hypothesis:
250-1350 CE—A Hemispheric‑to‑Global Warming Framework for the Maya Warm Period and Medieval Warm Period
Statement
The Maya Warm Period, the Medieval Warm Period (MWP), and contemporaneous regional warm/dry episodes (e.g., western North America ~10th–14th c.) were largely expressions of a single, multi‑century, hemisph eric‑to‑global warming episode. Regional heterogeneity in timing and magnitude reflects local feedbacks and heat‑transport pathways, while the underlying signal was amplified and sustained by a combination of external forcings, long‑lived internal ocean‑atmosphere variability, oceanic gyre and boundary‑current reorganizations, and substantial preindustrial land‑surface change.
Mechanisms (how a coherent large‑scale signal emerges despite regional differences)
—External forcings establishing a persistent warm baseline: Reconstructed solar irradiance and volcanic aerosol histories indicate intervals of relatively higher centennial solar forcing together with reduced cumulative explosive volcanic aerosol loading compared with adjacent centuries, producing a positive hemispheric background that raised baseline temperatures and favored ocean heat accumulation. Reduced frequency and magnitude of large explosive eruptions during parts of the interval lessened recurrent basin‑scale cooling, permitting decadal–centennial ocean heat uptake and persistence of a warm baseline.
—Internal climate variability as amplifier and organizer: Prolonged phases of modes such as the Atlantic Multidecadal Oscillation (AMO) and multidecadal Pacific states (PDO/IPO‑like) reorganized heat distribution, producing spatially coherent warm anomalies across the North Atlantic–European sector and amplifying terrestrial warmth in adjacent regions (Greenland, parts of Europe, eastern North America). Persistent ENSO tendencies and Pacific decadal variability propagated teleconnections with asynchronous but physically linked regional responses.
—Oceanic integration, gyre response, and propagation of heat:The ocean integrates surface forcings and redistributes heat via gyres, western boundary currents, and thermohaline adjustments. Evidence from sediment cores, corals, sclerosponge records, and foraminifera indicates decadal–centennial SST and circulation variability in subtropical and subpolar gyres and boundary currents across the North Atlantic, North Pacific, and South Pacific margins during the first and second millennia CE. Gyre shifts and strengthening of poleward heat transport (e.g., North Atlantic subtropical gyre/AMOC influence) plausibly transmitted and extended regional warm anomalies (AMO‑related) into Europe and Greenland, while Pacific gyre and eastern boundary current changes affected eastern Pacific SSTs and upwelling adjacent to Mesoamerica. These marine processes would produce remote teleconnections that link oceanic and terrestrial responses across basins.
—Land‑surface feedbacks producing amplified terrestrial signals: Vegetation change (treeline advance), soil drying, reduced evapotranspiration, lowered albedo from deforestation or burned landscapes, and glacier retreat amplified warming over land and modified regional circulation patterns, explaining stronger terrestrial signals (e.g., western North American drought and warmth, Mesoamerican aridity) relative to marine records.
—Compound small eruptions and long‑term volcanic landscape impacts: Clustered small–moderate eruptions produced episodic aerosol forcing superimposed on a warm baseline and caused long‑term biogeophysical impacts (tephra effects on soils, vegetation loss, fire outbreaks) that modulated decadal variability but did not eliminate the multi‑century warming tendency. Regional volcanic series (e.g., Long Valley activity ~900–1350 CE) likely produced localized landscape impacts and intermittent aerosol forcing that punctuated the broader warm epoch.
—Preindustrial anthropogenic land use as a reinforcing agent: Widespread preindustrial deforestation, agricultural expansion, and landscape burning (notably in Mesoamerica, parts of Europe and Asia) altered surface albedo, evapotranspiration, and regional carbon fluxes sufficiently to reinforce local warming and drying. Spatial correspondence between paleo‑ecological land‑use markers and amplified terrestrial warming supports a role for anthropogenic biogeophysical forcing in strengthening regional expressions of the larger climate anomaly.
Ocean integration and gyre involvement (summary of relevant marine signals)
• North Atlantic: Multiproxy records (foraminiferal SST, alkenone SST, sortable silt, IRD flux) indicate enhanced North Atlantic warmth and reorganized circulation associated with a positive AMO‑like state during parts of the MWP, with strengthened subtropical gyre signals and increased poleward heat transport that link to European and Greenland warmth.
• North Pacific: Sediment cores and marine proxies from the western subtropical gyre, Kuroshio extension, and eastern boundary current margins show centennial shifts in SST, surface stratification, and current strength consistent with sustained Pacific decadal variability influencing North American west‑coast climate.
• South Pacific and eastern tropical Pacific margins: Coastal and offshore cores indicate episodic SST anomalies, altered upwelling intensity, and changes in subtropical gyre strength on multi‑decadal to centennial scales; these would affect coastal environments adjacent to Mesoamerica and South America and could relay heat via equatorial and subtropical pathways.
• Caribbean and eastern tropical Atlantic/Caribbean margin: Coral and sediment records show centennial‑scale SST variability and episodic warming events that align with terrestrial drought/warmth in surrounding regions.
• Gyre‑margin coherence: Cross‑basin syntheses reveal that gyre and boundary‑current responses were regionally coherent on centennial timescales, providing plausible pathways for redistribution of accumulated ocean heat originating from reduced volcanic cooling and sustained external forcing.
Predicted observable consequences (testable implications)
—Hemispheric mean and multiproxy coherence: Bias‑corrected multiproxy syntheses should show a broadly coherent positive hemispheric mean temperature anomaly over roughly 900–1350 CE, with terrestrial over‑representation accounted for in uncertainty estimates.
—Marine proxy response across gyres and margins: Expanded coral, sclerosponge, foraminiferal, and sediment records in under‑sampled gyre margins should show weak–moderate SST increases, shifts in stratification, and circulation changes consistent in phase with terrestrial warming once chronology and seasonal biases are resolved.
—Model reproducibility including gyre dynamics: Coupled model experiments that include plausible elevated solar forcing, reduced cumulative explosive volcanic aerosol loading, long‑lived AMO/ENSO/PDO phases, gyre and boundary‑current adjustments, distributed small volcanic pulses, and spatially explicit preindustrial land‑use/biogeophysical forcings should reproduce an elevated hemispheric mean with regionally heterogeneous patterns consistent with observed terrestrial and marine signals.
—Land‑use covariation with amplified warming: Paleoecological indicators of land‑use change (charcoal, pollen, archaeological clearance) should spatially covary with amplified local warming/drying beyond what external climate forcing alone predicts.
Regional extent, transport pathways, and the Maya portion
—AMO and North Atlantic influence: A strong AMO‑like state during the MWP plausibly drove contiguous warm anomalies from Europe into Greenland and parts of North America via enhanced northward heat transport; atmospheric teleconnections would distribute associated climatic effects downstream.
—Maya Warm Period and adjacent marine signals Terrestrial and archaeological records document pronounced warming/drying in the Maya region; targeted marine evidence from the Caribbean, western tropical Atlantic, and eastern tropical Pacific margins is sparser but indicates episodic SST anomalies, coastal current changes, and upwelling adjustments during centennial windows. Localized gyre and boundary‑current responses, rather than a uniform basin‑scale warming of the entire South Pacific gyre, are the most plausible oceanic mechanisms for transferring heat into marine regions adjacent to Mesoamerica. Even spatially patchy or coastal‑confined marine warming would strongly support oceanic involvement and strengthen the case that the Maya Warm Period was linked to larger basin and hemispheric processes.
Alternative explanations to be ruled out
• Purely independent, regionally confined drivers requiring implausibly synchronous, spatially disparate events to create the observed continental‑scale pattern.
• Pure internal variability producing a multi‑century hemispheric anomaly without consistent external forcing—this would require model demonstrations of centennial‑scale internal modes matching observed continental phasing and remains less likely given multi‑record evidence of external forcings and marine responses.
Research priorities to evaluate and falsify the hypothesis
• Densify marine proxy networks and improve chronology (corals, sclerosponge, foraminifera, alkenones, TEX86, marine laminates) in undersampled gyre margins and boundary currents (North Atlantic subtropical and subpolar margins, North Pacific subtropical gyre and Kuroshio extension, South Pacific margins, eastern tropical Pacific near Mesoamerica). • Produce high‑resolution, well‑dated multiproxy syntheses that correct for terrestrial sampling bias in hemispheric estimates and explicitly include marine gyre‑margin records. • Run coordinated model experiments that incorporate updated solar and volcanic forcing reconstructions, long‑lived oceanic mode prescriptions, explicit gyre and boundary‑current dynamics, distributed small volcanic aerosol inputs, and spatially explicit preindustrial land‑use/biogeophysical forcings. • Intensify paleoland‑use studies (charcoal, pollen, archaeological clearance) to quantify timing and magnitude of anthropogenic forcing relative to climate signals.
Conclusion
Multiple lines of physical reasoning—external forcing setting a warmer baseline, oceanic integration via gyres and boundary currents redistributing heat, amplification by land‑surface feedbacks, episodic volcanic pulses, and reinforcing preindustrial land‑use—collectively make it plausible that the Maya Warm Period, the MWP/MCA, and many regional warm/dry episodes were facets of a largely coherent hemispheric‑to‑global warming episode with strong regional modulation; targeted marine sampling of gyre margins, bias‑aware multiproxy syntheses, and coordinated model experiments can test and potentially falsify this hypothesis.
Selected references
Crowley, T.J. (2000). Causes of climate change over the past 1000 years. Science.
Fjordstad et al. (2019). Earth System Dynamics.
Gray, S.T., et al. (2004). A tree‑ring based reconstruction of the North Atlantic Oscillation. Geophysical Research Letters.
Mann, M.E., et al. (2009). Global signatures and dynamical origins of the Little Ice Age and Medieval Climate Anomaly. Science.
Cobb, K.M., et al. (2003). El Niño/Southern Oscillation and tropical Pacific climate during the last millennium from corals. Science.
Oppo, D.W., et al. (2009). Oceanic variability during the past millennia from marine sediment records. Paleoceanography.
Ruddiman, W.F. (2003). The anthropogenic greenhouse era began thousands of years ago. Quaternary Research.
Kaplan, J.O., et al. (2011). Climate and land‑use change impacts on the Holocene. The Holocene.
Zielinski, G.A., et al. (1996). Volcanic aerosol forcing reconstructions and climate impacts. Journal of Geophysical Research.
Bacon, C.R., et al. (2018). Tephra and landscape impacts from Long Valley volcanism.
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