Global warming, climate change, all these things are just a dream come true for politicians. I deal with evidence and not with frightening computer models because the seeker after truth does not put his faith in any consensus. The road to the truth is long and hard, but this is the road we must follow. People who describe the unprecedented comfort and ease of modern life as a climate disaster, in my opinion have no idea what a real problem is.
A recent article in The Conversation, โColonisation, not climate change, first primed these forests to burn,โ claims that changing forest management practices, or lack thereof, are primarily responsible for Australian wildfires getting out of control, and climate change is only part of the equation. This is true, at least in some respects. Low-intensity controlled burns and timber harvesting can prevent more intense fires from being able to get started, and many indigenous people frequently burned landscapes to improve hunting grounds.
A recent article in The Conversation, โColonisation, not climate change, first primed these forests to burn,โ claims that changing forest management practices, or lack thereof, are primarily responsible for Australian wildfires getting out of control, and climate change is only part of the equation. This is true, at least in some respects. Low-intensity controlled burns and timber harvesting can prevent more intense fires from being able to get started, and many indigenous people frequently burned landscapes to improve hunting grounds. This is true of European cultures as well, however, and the framing of this article makes the mistake of forwarding well-meaning but still racist โnoble savageโ tropes.
The post authors, researchers from the University of Melbourne along with an Aboriginal โTraditional Custodian,โ correctly state that โweather is only part of a catastrophic fire.โ
They emphasize fuel load as a major component that contributes to out of control, devastating wildfires. Their research focused on the evidence of more frequent, low-intensity fires occurring in the ancient past of Australia, which suddenly stop after British colonization of the continent. They assert that โcurrent fuel loadโ in Australian forests is due to human intervention, in this case because controlled burning was discontinued after the Aboriginal people were displaced.
The authors โfound that for more than 800 years, frequent, low-temperature cultural burning under GunaiKurnai care held this land as stable, open woodland,โ and after colonization, โ[h]ot fire becomes dominant, shrubs thicken, eucalypt cover surges to nearly four times pre-colonial levels, and open woodland becomes todayโs flammable forest.โ
They still make nods towards what they call โhuman-driven climate change,โ but acknowledge that it โdid not start this vulnerability โ it amplifies one that colonisation began.โ
There are a few angles at work here, but first I will note that they are correct that controlled burning reduces fuel load and thus makes it harder for very hot fires to get started.
A major mistake of environmentalists of the past several decades was to stop timber harvesting and deadfall clearing, and limit even low intensity natural burns. Climate Realism explains how in posts about California, Texas, and Canada, among others. Environmental goals, like saving the Spotted Owl for instance, seen in Figure 1 below, led to the building up of burnable fuel that can explode into intense wildfires when an arsonist or lightning strikes.
Figure 1. Graph combining data for Federal lands showing acres harvested vs. acres burned, in millions of acres. Data from U.S. Forest Service and the National Interagency Fire Center. Graph by Anthony Watts.
Incorrect in the Conversation piece, however, is the assertion that climate change is making wildfires worse at all. The data simply do not show it, satellite data show that global wildfire occurrence has been on a downward trend for decades. (See Figure 2 below)
Figure 2: Total acreage burned by fires each year between 2003 and 2015. Trend line in red indicates a steady decline. Source: โNASA detects drop in global fires,โ NASA website, June 29, 2017.
Similarly, data show that Australian wildfires are also becoming smaller since peaking in the 1970s, there is no trend towards more or worse drought. If anything, as pointed out in โClimate Blame for Australian Wildfires Ages Poorly, as Rainfall Remains Abundant,โ precipitation seems to be improving for the continent since the droughts of the mid-twentieth century.
The authors are probably right that when the previous owners of the land, Aborigines, were pushed out, the land management practices changed. Itโs not clear from the article whether the researchers determined with certainty that the frequent low-intensity fires were directed by Aborigines, or just at times allowed to burn when they started naturally.
Their solution is that โTraditional Ownersโ โ that is to say, Aboriginesโmust be โresourcedโ so they can restore โhealthy Country and cultural burning.โ
They do not explain how Aboriginal โcultural burningโ is better than normal controlled burning that is done in other parts of the world, one suspects that it is not very different.
Ancient Europeans practiced forest and moorland management as well, thinning forests via logging and controlled burns on the moors were practiced by the British. It is nonsense to imply that white settlers were unaware that these methods helped to maintain healthy woodlands. It is a sort of โnoble savageโ fallacy being pushed here, that native people were living in harmony with nature, and not constantly battling it, compared to the foolish nature-hating Europeans. Controlled or cultural burning is not, definitionally, living in harmony with nature. It is aggressive management and shaping the land to your own wants and needs, and the Aborigines themselves know this, as they say in the article, โwild Country is sick Country.โ
Today, you canโt blame wildfires in Australia on British colonists; a better argument can be made that progressive environmentalists are the ones currently responsible.
It is good that The Conversation allowed any article that explains something as straightforward as the fact that fuel load is more to blame for severe fires than climate change, but it is shameful that it appears the only way this can get published is by making the lede about scolding the British.
U.S. oil and gas methane emissions remained essentially flat from 2019- 2024 even as production rose, according to a Johns Hopkins University study led by Ao Chen (PhD student) and Scot Miller (associate professor of environmental health and engineering), published in Communications Earth & Environment.
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U.S. oil and gas methane emissions remained essentially flat from 2019- 2024 even as production rose, according to a Johns Hopkins University study led by Ao Chen (PhD student) and Scot Miller (associate professor of environmental health and engineering), published in Communications Earth & Environment.
The researchers used satellite observations from TROPOMI and GOSAT combined with atmospheric inverse modeling to estimate emissions across the contiguous U.S. Total oil and gas methane emissions stayed in a narrow range of about 9.3-10.4 teragrams (Tg) per year. They fell by 0.58 Tg from 2019- 2023 but rose slightly from 2023- 2024. Emissions intensity (methane released relative to oil and gas production) dropped by roughly 11%, continuing a longer- term downward trend rather than reflecting a sharp new policy- driven decline.โ
Key points from the study and related coverage:
Good news and bad news framing: Emissions did not surge despite major growth in production (especially after the hydraulic fracturing boom), contrary to some earlier fears. However, oil and gas remain a large share of U.S. methane emissions, and the data show no clear detectable drop attributable to recent federal measures such as the Inflation Reduction Actโs methane fees and Waste Emissions Charge or EPA Clean Air Act rules. Researchers note the counterfactual is unknown; emissions might have been higher without the policies.โ
Drivers of stable absolute emissions and falling intensity: Improved infrastructure (more pipelines to capture and sell gas instead of flaring and venting it, especially in places like the Permian Basin), better industry practices and leak detection and repair, earlier regulations (e.g., New Source Performance Standards for newer facilities), and the rising economic value of natural gas as a commodity. Most of the intensity decline occurred around 2020- 2022.โ
Regional variation: Texas saw a roughly 14% decline in oil and gas methane emissions. California and Colorado appear to be falling short of their own reduction goals. States with statutory targets sometimes have better inventory alignment with satellite data, but this did not clearly translate into faster emission reductions than states without such targets.โ
Context on policy and inventories: Implementation of the IRA fee and related rules faced delays and was limited during the study window. Satellite- based estimates remain higher than EPA Greenhouse Gas Inventory figures (consistent with prior top-down studies), though they capture a similar intensity trend.โ
Methane is a potent short- lived greenhouse gas (roughly 30 times more powerful than COโ over short timescales), so absolute reductions matter for near- term climate impact.
The authors emphasize that while falling intensity is positive, sustained cuts in total emissions are still needed, and long- term regulatory consistency could influence future industry incentives.
The original Johns Hopkins Hub article (by Hannah Robbins, published October 13, 2026) is available at hub.jhu.edu. The peer- reviewed paper is in Communications Earth & Environment (DOI related to 10.1038/s43247-026-04039-0).
TROPOMI and GOSAT provide key satellite observations of atmospheric methane (CHโ) used in the Johns Hopkins study and many other emissions analyses.
In that research, scientists combined data from these instruments with atmospheric modeling. Because methane disperses with wind, they applied inverse modeling (an algorithm that works backward from observed atmospheric concentrations) to estimate where and how much methane was emitted from oil and gas sources on the ground across the contiguous U.S. for 2019- 2024.
TROPOMI (TROPOspheric Monitoring Instrument)
Platform: Onboard the European Space Agencyโs (ESA) Sentinel- 5 Precursor satellite, launched in October 2017.
Capabilities: A push- broom imaging spectrometer that measures reflected sunlight across ultraviolet, visible, near-infrared, and shortwave infrared (SWIR) bands. Methane is retrieved primarily from the SWIR band around 2.3 ฮผm.
Coverage and resolution: Daily near- global coverage with a wide ~2,600 km swath. Nadir pixel size is about 7 ร 7 km (improved to ~5.5 ร 7 km after August 2019).
Strengths: High spatial resolution and dense sampling enable mapping of both regional patterns and some larger point sources. It produces column- averaged dry- air mole fractions of methane (XCHโ).
Limitations: Strict quality filtering yields a relatively low retrieval success rate (~3% in some analyses) due to clouds, aerosols, and surface conditions. It can show larger regional biases (especially over low- albedo surfaces) compared with more mature instruments. Reported precision is around 0.6%.
GOSAT (Greenhouse gases Observing SATellite)
Platform: Japanโs GOSAT series (first satellite, nicknamed โIBUKIโ, launched in 2009; successor GOSAT- 2 launched in 2018). Operated by JAXA with involvement from Japanโs Ministry of the Environment and National Institute for Environmental Studies.
Capabilities: Dedicated greenhouse- gas mission using Fourier- transform spectrometers (TANSO-FTS / TANSO- FTS-2) to measure COโ and CHโ columns via solar backscatter in the SWIR.
Coverage and resolution: Sparser sampling, circular pixels of ~10.5 km diameter, typically spaced hundreds of kilometers apart, with a multi- day revisit cycle (e.g., ~3 days in standard mode for the original GOSAT). Higher retrieval success rate (~24%, limited mainly by clouds) than TROPOMI.
Strengths: More mature retrievals with generally lower biases. Often used as a reference or for bias correction of denser datasets like TROPOMI. Precision is typically reported around 0.7%. It has provided a long- term record of global methane trends since 2009.
Limitations: Much lower data density (roughly 100- 250 times fewer observations than TROPOMI in comparable periods), which limits fine- scale mapping.
How they are used together
TROPOMI supplies dense, high- resolution coverage, while GOSAT offers higher- accuracy, lower- bias measurements. Many studies (including the Johns Hopkins work) blend or jointly assimilate the two datasets. Machine- learning approaches are sometimes applied to correct TROPOMI biases relative to GOSAT (e.g., adjusting for aerosols, surface albedo, or viewing geometry). Validation against ground-based networks such as TCCON typically shows small global mean biases for both (often a few ppb), though regional differences can exceed 10- 20 ppb in challenging conditions.
These satellite XCHโ observations enable independent, top- down estimates of emissions that complement bottom- up inventories (such as the EPAโs Greenhouse Gas Inventory). In the Johns Hopkins analysis, the combined data supported the conclusion that U.S. oil and gas methane emissions stayed relatively flat (~9.3- 10.4 Tg/year) while intensity declined ~11% amid rising production.
U.S. oil and gas methane emission intensity declined 2019โ2024 with little indication of federal policy impact
U.S. oil and gas methane emissions remained essentially flat from 2019 to 2024 even as production increased, according to a Johns Hopkins University study.
The research, led by PhD student Ao Chen and senior researcher Scot Miller (associate professor of environmental health and engineering), was published in Communications Earth & Environment. It is covered in a Johns Hopkins Hub article by Hannah Robbins (published October 13, 2026).
Key findings
Researchers combined satellite data from TROPOMI and GOSAT with atmospheric inverse modeling to estimate emissions across the contiguous United States.
Total methane emissions from oil and gas activities stayed between roughly 9.3 and 10.4 teragrams (Tg) per year.
Emissions declined by 0.58 Tg from 2019- 2023, then rose slightly from 2023- 2024.
Emissions intensity (methane released relative to oil and gas production) fell by about 11%. This continues a longer-term downward trend rather than reflecting a sharp drop driven by recent policy.โ
Miller described it as a โgood news/bad news situationโ: emissions did not surge as some had feared amid major production growth (especially after the hydraulic fracturing boom), but oil and gas still account for a large share of U.S. methane emissions, and the study found no clear detectable reduction attributable to recent federal measures such as the Inflation Reduction Actโs methane- related provisions or related EPA rules. The authors note it is impossible to test the counterfactual; emissions might have been higher without those policies.
Why emissions stayed flat while production rose
Contributing factors include expanded pipeline infrastructure (allowing more gas to be captured and sold instead of flared or vented, particularly in areas like the Permian Basin), improved industry practices and leak detection, earlier regulations on newer facilities, and the rising economic value of natural gas as a commodity. Better protocols and reduced flaring have helped lower intensity even as overall output grew.
Regional notes
Texas (home to the largest oil- producing basin) saw an approximately 14% decline in oil and gas methane emissions. California and Colorado appear to be falling short of their own reduction goals.โ
Methane is a potent, shorter- lived greenhouse gas (roughly 30 times more powerful than COโ over short timescales). The authors stress that while falling intensity is positive, meaningful climate impact requires reductions in absolute emissions, and longer-term regulatory consistency may be needed to further incentivize cuts.
The original Hub article is available at hub.jhu.edu.
The U.S. federal government undertook a historic legislative effort to regulate methane emissions from the oil and gas sectors beginning in 2021 through the Inflation Reduction Act and Waste Emissions Charge. Despite a substantial rollback of these regulations in subsequent years, U.S. oil and gas methane emissions during this policy window are largely uncharacterized. Here we estimate changes in U.S. methane emissions both before and directly after this policy window (years 2019 to 2024) using an inverse model constrained by satellite observations. Overall, we find that oil and gas methane emissions decreased by 0.58 [0.30, 0.96] Tg from 2019 to 2023, but increased by 0.21 [-0.06, 0.53] Tg in the years following the new federal policy (2023โ2024). We find that methane emissions intensity declined by 11.1% [9.3%, 13.6%] from 2019 to 2024, likely as a result of gradual technological and operational developments, and existing federal regulations.
The Trump administration is preparing to scrap another Biden-era climate regulation, taking aim at a methane leak program that federal officials argue has burdened American oil and gas producers with billions in costs.
Former President Joe Bidenโs EPA finalized sweeping methane regulations in 2023, later establishing the super-emitter program as part of its 2024 oil and natural gas rules. The administration projected that the broader regulations would prevent approximately 58 million tons of methane emissions between 2024 and 2038.
Gas price. Rise in gas prices in USA. A burner with a flame and an arrow up, painted in the colors of the USA flag. The concept of rising gas or energy prices.
The Trump administration is preparing to scrap another Biden-era climate regulation, taking aim at a methane leak program that federal officials argue has burdened American oil and gas producers with billions in costs.
Environmental Protection Agency (EPA) Administrator Lee Zeldin announced Wednesday that the agency will soon propose eliminating the Biden administrationโs โsuper-emitterโ program, which requires oil and gas operators to investigate reports of major methane leaks detected by third parties. The announcement came during an oil and gas industry meeting in Santa Fe, New Mexico.
Former President Joe Bidenโs EPA finalized sweeping methane regulations in 2023, later establishing the super-emitter program as part of its 2024 oil and natural gas rules. The administration projected that the broader regulations would prevent approximately 58 million tons of methane emissions between 2024 and 2038.
โIn an upcoming proposal, which is currently under review by the Office of Management and Budget, U.S. EPA will take an important step in easing regulatory burdens and unleashing the Nationโs domestic energy supply by proposing the next step in the agencyโs wide-scale reconsideration of the Biden-Harris Administrationโs Clean Air Act rules for the oil and natural gas industry,โ an EPA spokesperson told the Daily Caller News Foundation.
โBehind every barrel of oil and every cubic foot of natural gas produced in the U.S. are millions of workers, businesses, and the heartbeat of this nationโs economy; the Biden-era regulations posed a monumental threat,โ the spokesperson continued. โAs a result, Americans in every state suffered from higher energy prices. The U.S. produces energy in a better and more environmentally friendly way than anywhere else in the world.โ
The EPA estimates its broader proposed changes to the Biden-era oil and gas regulations would save $45 billion, according to the Wednesday press release. The agency also argues that the super-emitter program is ineffective and unnecessary to satisfy Clean Air Act requirements.
โThe Trump EPA knows our policies must match our nationโs potential and is working to unleash the full ability of American energy and lower costs for Americans by returning commonsense to regulations. The proposal will be released once it has been signed by the Administrator.โ
Methane, however, has become a major target of climate activists because of its ability to trap heat in the atmosphere. NASA identifies methane as the second-largest contributor to global warming behind carbon dioxide, estimating that rising methane concentrations have accounted for 20% to 30% of Earthโs warming since the Industrial Revolution.
The gas is also considerably more potent than carbon dioxide over shorter periods. One ton of methane can trap 84 to 87 times as much heat as a ton of carbon dioxide over 20 years, according to NASA. Methane generally remains in the atmosphere for only about a decade, compared with the centuries that carbon dioxide can persist.
Today, EPA Admin. Zeldin announced a rollback of federal rules that ensure oil and gas operators don't pollute our air. This decision clearly shows that Trump is putting polluters first over the wellbeing of the American people. #Methanepic.twitter.com/ZHumKW2iXj
— Conservation Voters New Mexico (@ProtectNM) October 7, 2026
Methane emissions are not exclusive to fossil fuel production. Agriculture, landfills and natural wetlands also release the gas, with NASA estimating that roughly 60% of global methane emissions come from human activities.
The super-emitter program allows EPA-certified groups, including nonprofit Carbon Mapper, to use satellites, aircraft and other technologies to detect methane leaks of at least 100 kilograms per hour, according to the agency.
Operators receiving qualifying notifications must investigate the suspected leaks, report their findings and make repairs when required under applicable EPA standards.
The Trump administration previously delayed future implementation of the program until January 2027. Its latest announcement goes further, proposing to eliminate the program altogether.
The proposed rollback comes as the administration continues dismantling Biden-era environmental regulations. The EPA previously repealed greenhouse gas standards for coal- and natural gas-fired power plants, a move the agency estimated would eliminate more than $300 billion in regulatory costs, as the Daily Caller News Foundation previously reported.
โAmericans must be able to afford to heat their homes in the winter and fill up their car and drive to work. They canโt do that when the people producing the energy are weighed down by unnecessary burdens,โ Zeldin said in the EPAโs press release. โThe Trump EPA is committed to fixing this so the U.S. can reach its full energy potential.โ
Scientists found evidence that Earthโs mantle was interacting with (and being oxidized by) surface oxygen as early as ~3.4 billion years ago, roughly a billion years before the Great Oxidation Event permanently raised atmospheric oxygen levels around 2.3- 2.2 billion years ago.
Sanukitoid petrogenesis refers to the origin and formation processes of a distinctive suite of intermediate to felsic igneous rocks (mainly diorites, monzodiorites, granodiorites, and related rocks) that are characteristic of the late Archean to early Paleoproterozoic (~3.0- 2.5 Ga, with some earlier examples from ~3.4- 2.9 Ga).
Early subduction involving inorganic oxidation and intermittent โwhiffsโ of oxygen between 3.4 and 2.7 Ga may have driven an early rise in sub-arc mantle fugacity before the Great Oxidation Event (GOE, ~2.3-2.2 Ga), reaching conditions comparable to the modern Earth by ~2.1 Ga.
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Scientists found evidence that Earthโs mantle was interacting with (and being oxidized by) surface oxygen as early as ~3.4 billion years ago, roughly a billion years before the Great Oxidation Event permanently raised atmospheric oxygen levels around 2.3- 2.2 billion years ago.
This comes from a University of Portsmouth- led international study published in Nature Geoscience (DOI: 10.1038/s41561-026-02119-6; lead author Dr. Hugo Moreira). It builds on earlier 2023 work by the same group linking mantle chemistry changes to the Great Oxidation Event itself.
Key methods and findings
Researchers analyzed tiny โtime capsulesโ: apatite mineral inclusions sealed inside durable zircon crystals from sanukitoid rocks (a distinctive type of magma linked to early subduction- like processes). Samples spanned more than 3 billion years and came from sites including the Pilbara Craton (Australia; ~3.42 and 2.9 Ga), Karelian and Kaapvaal Cratons (Finland and South Africa; ~2.7 Ga), Sรฃo Francisco Craton (Brazil; ~2.13 Ga), and Scotland (~425 Ma).โ
Zircons were dated precisely (some to exactly 3.4 billion years old) using laser techniques at Portsmouth.
Sulfur oxidation states (Sโถโบ, Sโดโบ, Sยฒโป) in the protected apatite inclusions were measured via sulfur K-edge micro- X- ray absorption near- edge structure (XANES) spectroscopy at the European Synchrotron Radiation Facility (ESRF) in France. These states act as a sensitive proxy for oxygen fugacity (how oxidizing the magma and mantle environment was).โ
Results show a progressive increase in oxygen fugacity in the sub-arc mantle starting between ~3.4 and 3 billion years ago. The signature remained present across the studied interval and approached modern levels by ~2.1 billion years ago. This indicates that subduction was already recycling oxidized surface material (from early weathering and intermittent โwhiffsโof oxygen) deep into the mantle long before permanent atmospheric oxygenation.โ
The team ruled out alternative explanations (temperature and pressure variations, fractional crystallization, degassing) and noted that even small amounts of oxidized sulfur would have had a strong effect on the more reduced early mantle.
They propose feedback: early oxidative recycling raised sub-arc mantle oxidation โ more oxidizing volcanic gases โ more felsic crust and intensified surface weathering โ further contribution to long- term atmospheric oxygen buildup.
This provides the most continuous timeline yet of how surface oxygen and deep- Earth processes co-evolved. It supports the idea that plate tectonics (or early analogs) connected Earthโs exterior and interior reservoirs far earlier than often assumed, helping create conditions for a habitable planet.
The work is curiosity- driven basic research into Earthโs origins and the emergence of life, rather than an immediate practical application.โ
In short, the mantle was effectively โbreathingโ (exchanging and responding to) oxygen via recycling processes a billion years before free oxygen dominated the atmosphere.
Earth’s First ‘Breath’
Sanukitoid petrogenesis refers to the origin and formation processes of a distinctive suite of intermediate to felsic igneous rocks (mainly diorites, monzodiorites, granodiorites, and related rocks) that are characteristic of the late Archean to early Paleoproterozoic (~3.0- 2.5 Ga, with some earlier examples from ~3.4- 2.9 Ga).
They mark a transitional phase in Earthโs crustal evolution, bridging the dominant Archean tonalite- trondhjemite- granodiorite (TTG) magmatism and more modern- style calc- alkaline arc magmatism.
Geochemical Characteristics
Sanukitoids are defined by a dual โmantle and crustโ signature:
Mantle- compatible elements: High MgO (typically 1.5โ9 wt%), Mg# (molecular Mg/ (Mg and Fe) โ 45โ65 or higher in primitive members), Ni (>100 ppm in many definitions), Cr (>100- 200 ppm).
Incompatible elements: Strong enrichment in large- ion lithophile elements (LILE), especially KโO (1.5โ5 wt%), Ba, and Sr (Ba and Sr often >1,000โ1,400 ppm); high light rare- earth elements (LREE); relatively high KโO/NaโO compared with TTGs; fractionated REE patterns with low HREE and no or minor Eu anomalies.โ
Classic strict definition (Stern et al., 1989) focused on SiOโ 55โ- 60 wt% with the above traits, but the broader โsanukitoid suite and seriesโ includes more evolved members produced by fractional crystallization. High- Ti and low- Ti varieties are sometimes distinguished.
They resemble high- Mg andesites (sanukites) from the Setouchi volcanic belt in Japan, hence the name.
Petrogenetic Models
The consensus is that sanukitoids form by interaction between mantle peridotite and a recycled crustal component (typically TTG- like or slab- derived felsic melts, possibly with fluids and/or sediments).
Two main (not mutually exclusive) pathways are debated:
Two- stage (metasomatism and later melting) process (most widely invoked)
Stage 1: Subduction- related fluids and or silicate melts (from partial melting of subducted oceanic crust and metabasite, often eclogite- facies, ยฑ sediments) metasomatize the mantle wedge or subcontinental lithospheric mantle. This creates enriched domains (e.g., amphibole- or phlogopite- bearing veins).
Stage 2: Later thermal perturbation (slab break-off, mantle plume, or continued subduction heating) causes partial melting of this metasomatized peridotite, generating the sanukitoid parental magma.โ
One- stage (assimilation and reaction) process
TTG- like or hydrous eclogite melts directly react with and assimilate mantle peridotite during ascent, producing hybrid melts with the characteristic dual geochemistry.โ
Recent Ti- isotope studies (ฮดโดโนTi) of primitive sanukitoids show elevated values requiring a hydrous metabasite (eclogite) melt component formed in equilibrium with residual rutile. This favors fluid- fluxed melting of eclogite in a subduction- like setting and indicates parental magmas were water- rich and relatively oxidized, comparable to modern arc magmas.โ
Melting conditions are typically high- pressure (>1- 2.5 GPa, corresponding to ~35- 80 and km depth), hydrous, and oxidized. Differentiation often involves amphibole ยฑ plagioclase ยฑ orthopyroxene fractionation, sometimes at lower pressures where a distinct cotectic may control the series.
Geodynamic Significance
Sanukitoids appear mainly near the Archean- Proterozoic transition and are linked to the progressive cooling of Earth and the evolution of subduction:
Early Archean: High heat production favored extensive slab melting โ pure TTG magmas with limited mantle interaction.
Late Archean: Reduced slab melting โ more interaction with the mantle wedge โ sanukitoids (hybrids).
Post ~2.5 Ga: Predominantly fluid- fluxed melting of the mantle wedge (modern- style arcs), with slab melts rarer.โ
They are therefore key evidence for the onset or maturation of plate- tectonic (or proto- subduction) processes, deep crust- mantle recycling, and the changing nature of continental crust growth.
In the context of the recent Nature Geoscience study on mantle oxidation, sanukitoids serve as excellent monitors of sub- arc mantle redox state because their sources record metasomatism by recycled surface materials.
Modern Analogues and Distribution
Phanerozoic high- Mg diorites, vaugnerites, appinites, and some post-collisional I- type granitoids share similarities and may represent analogues. Archean examples occur worldwide (e.g., Superior Province, Pilbara, Kaapvaal, Karelian, North China, Amazonian/Carajรกs, Yilgarn, and Sรฃo Francisco cratons).
In summary, sanukitoid petrogenesis records hybridization between depleted mantle and recycled crustal melts and fluids in a subduction- related setting under hotter Archean conditions.
This dual signature makes them invaluable for tracking early Earth geodynamics, mantle metasomatism, and the co- evolution of crust and mantle.
Progressive oxidative weathering raised sub-arc mantle fugacity on the Archaean Earth
Abstract (summary)
In the modern Earth, sub- arc mantle oxygen fugacity is linked to addition of sulfur species by slab fluids. It has been unclear to what extent volatile recycling controlled redox changes in the early Earth.
Using sulfur K -edge micro- X- ray absorption near- edge structure (ฮผ-XANES) spectroscopy, the authors measured the relative abundances of Sโถโบ, Sโดโบ, and Sยฒโป in apatite inclusions hosted in geochemically characterized and precisely dated zircons from sub- arc sanukitoid magmas spanning 3.4 billion years of Earth history.
Key results:
The sub- arc mantle shows a marked increase in oxygen fugacity (fOโ) between 3.4 and 3.0 Ga.
It is substantially more oxidized than the unaltered ambient upper mantle.
This cannot be explained by fractional crystallization, degassing, or intrinsic mantle processes.
The authors propose that progressive oxidative weathering increased the proportion of oxidized sulfur recycled into mantle- wedge sources.
This established a feedback between subduction of surface materials and progressively more oxidized arc magmatism.
Early subduction involving inorganic oxidation and intermittent โwhiffsโ of oxygen between 3.4 and 2.7 Ga may have driven an early rise in sub-arc mantle fugacity before the Great Oxidation Event (GOE, ~2.3-2.2 Ga), reaching conditions comparable to the modern Earth by ~2.1 Ga.
Methods highlights
Samples: Geochemically coherent sanukitoids (metasomatized- mantle- derived magmas) from the Pilbara Craton (Australia; 3.42 and 2.9 Ga), Karelian Craton (Finland; 2.7 Ga), Kaapvaal Craton (South Africa; 2.7 Ga), Sรฃo Francisco Craton (Brazil; 2.13 Ga), and Northern Highland Terrane (Scotland; 0.425 Ga).
337 analyses on 39 apatite inclusions + 213 analyses on 65 matrix apatites, performed at the European Synchrotron Radiation Facility (ESRF, ID21 beamline).
Sโถโบ/S_total ratios converted to ฮFMQ (deviation from the fayalite- magnetite- quartz buffer) using an experimental oxybarometer.
Supporting U- Pb dating, trace- element, and oxygen- isotope data on the host zircons.
Broader implication
This provides the first continuous record showing that surface oxidative weathering products were already being recycled into the deep Earth via early subduction- like processes more than a billion years before permanent atmospheric oxygenation. The mantle was not a passive spectator; it participated in a feedback loop that helped shape the conditions leading to a habitable, oxygenated Earth.
In the modern Earth, sub-arc mantle oxygen fugacity is intrinsically associated with addition of sulfur species by slab fluids. However, it is unclear to what extent recycling of volatiles controlled redox changes of the sub-arc mantle in the early Earth. Here we use sulfur K-edge micro-X-ray absorption near-edge structure spectroscopy to measure the relative abundances of S6+, S4+ and S2โ in apatite inclusions hosted by geochemically characterized and dated zircons from sub-arc sanukitoid magmas that span 3.4 billion years of Earthโs geological history. The sub-arc mantle shows marked increase in oxygen fugacity between 3.4 and 3.0 billion years ago (Ga). It is substantially more oxidized than unaltered ambient upper mantle, a characteristic that cannot be explained by fractionation, degassing or intrinsic mantle processes. We propose that progressive oxidative weathering enhanced the proportion of oxidized sulfur recycled to mantle wedge sources, establishing feedback between subduction of surface materials and incrementally oxidized arc magmatism. Early subduction involving inorganic oxidation and โwhiffsโ of oxygen between 3.4 and 2.7 Ga may have regulated an early increase in fugacity of the sub-arc mantle before the Great Oxidation Event, matching similar conditions to the modern Earth by 2.1 Ga.
Kim Rogalin posted about the controversy over the (now removed) 4th edition of the Federal Judicial Center’s Reference Manual on Scientific Evidence from the National Academy of Sciences.
Bradley says his points about RCP 8.5 were never directly answered, and that Climategate should not be forgotten, quoting Andrew Dessler from 2009 calling the emails “embarrassing and a public-relations disaster for science.”
The problem with that chapter centered on the fact it was not neutral or unbiased, as the science manual is supposed to be, but was written by activist lawyers and academics actively involved in climate lawsuits filed across the nation, plus plaintiffs, advisors, and climate experts participating in those trials. Being written by public advocates of climate lawsuits, while citing materials and using whole sections written by attorneys and academics testifying for the plaintiffs in those lawsuits, doesnโt just tiptoe along the line of the appearance of impropriety. It is flat-out improper and should have been sufficient by itself to disqualify the climate science document from inclusion in the FJC science manualโฆ.
The Academy did the right thing by removing the climate chapter from its website and formally investigating.
Jim Cooper Exchange
Enter Jim Cooper, Professor Emeritus at the University of Minnesota, who commented.
What BS. Members of National Academy of Sciences are elected based of quality of their scientific research not their political positions. Members are elected โฆ in recognition of their distinguished and continuing achievements in original research. Membership is a widely accepted mark of excellence in science and is considered one of the highest honors that a scientist can receive. Current NAS membership totals approximately 2,700 members and 500 international members, of which approximately 200 have received Nobel prizes.โ [NAS here]
I then engaged him as follows:
Bradley: Shame that climate science ruined the reputation of science in general. From Climategate to RCP 8.5.
Jim Cooper: No the shame is folks unwillingness to read the scientific literature . As retired scientist and Scientific Journal Editor, I know that the scientific evidence for Climate Change is robust and the quality of the research on par with other scientific fields. The exchange of personal opinions in a few emails did not affect the quality of the published research. I challenge you to prove otherwise using links to credible documentation.
Bradley: Are/were you part of the problem? Climategate was about real-time cheating for โthe causeโ (and getting called out for it) and an admitted promise to attempt to skew peer review. Read the quotations! Secondly, what about all the journal articles based on RCP 8.5. Retraction? Climate models are not scienceโฆ.
Bradley: What about the busted paradigm of RCP 8.5-based peer-reviewed articles? Why did the profession turn the speculative (and now rejected) model scenario into a base case? Politicization or mass intellectual error?
Cooper: Again and again I will remind you and others that posts without links to credible domination for claims are noise. Links please, otherwise I will not respond.
Bradley: It is international news in the climate community that RCP 8.5 was formally rejected after a decade of primary use. It was the basis for literally thousands of published climate articles. Roger Pielke Jr. has covered this in detail. Are you following the debate? So again my question: โWhat about the busted paradigm of RCP 8.5-based peer-reviewed articles?โ rogerpielkejr.substack.com/p/rcp85-is-officially-dead
Conclusion
My points were never directly answered by the self-anointed authority. If I had made the same case in a journal article, providing a link, what would Cooper have said? My guess is that he would state that it was not a quality journal. Such is the narrative that the experts do not want to disturb.
Climategate livesโand should never be forgotten. As a leading climate alarmist-qua-scientist, Andrew Dessler, stated back in 2009: โThere is no doubt that these emails are embarrassing and a public-relations disaster for science.โ
Jim Cooper Background
In a previous Facebook post concerning the Climate Change Reality Forum, Cooper wrote:
The goal of this site is: โThe Climate change reality forum is an open Facebook group established to reach people with information that differs from the IPCCโs official position on this subject.โ IPCC presents scientific research findings and the only valid debate must be with scientific research findings accompanied by full citation of sources not opinions. But I find that the latter predominant thus are not honest discussions of reality.
This led to more than one hundred comments, with Cooper responding to criticism by stating:
Itโs your responsibility to prove your claims using data and/or previous published research findings. Thatโs part of critical thinking, and I repeat in science all statements and/or claims must be backed by citation of credible documentation. Please provide a link to paper where the figure appearsโฆ.
How trueโexcept when it comes to climate science and other politicized areas of scientific research.
The first human inhabitants of the Japanese archipelago have been traced to the Paleolithic, around 38- 39,000 years ago. The Jลmon period followed, lasting roughly from c. 14,000- 13,000 BC to about 1000- 300 BC.
Over 10,000- 14,500 Paleolithic sites are now known across the archipelago, one of the densest concentrations in the world, aided by widespread volcanic tephra layers (especially the Aira- Tanzawa tephra) that provide excellent chronological markers.
The Paleolithic ends with the appearance of pottery (among the worldโs oldest) around 16,000- 14,000 years ago. This marks the beginning of the Jลmon culture, characterized by greater sedentism, more complex hunter- gatherer adaptations, and the famous cord- marked ceramics.
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The first human inhabitants of the Japanese archipelago have been traced to the Paleolithic, around 38- 39,000 years ago. The Jลmon period followed, lasting roughly from c. 14,000- 13,000 BC to about 1000- 300 BC.
Paleolithic period
Hunter- gatherers reached the islands during the Late Pleistocene. Reliable archaeological evidence places the earliest human presence at approximately 38- 40,000 years ago (some sites, such as Lake Nojiri, yield dates near 37,900 years BP).
Japanโs acidic soils preserve few bones, so the record rests mainly on stone tools, including distinctive edge- ground axes more than 30,000 years old. People almost certainly arrived by watercraft; land bridges existed at times of lower sea level, but the islands were not continuously connected.
Sites on Okinawa (Yamashita Cave, ~32,000 years ago) and Ishigaki further document early settlement. These groups hunted now- extinct megafauna such as the elephant Palaeoloxodon naumanni and the giant deer Sinomegaceros yabei.
Jลmon period
Named for its characteristic cord-marked (jลmon) pottery, among the worldโs oldest ceramics, appearing by ~16,500- 14,000 years ago, the period is defined by a predominantly hunter- gatherer culture that achieved notable sedentism and complexity.
People lived in pit dwellings, exploited rich marine and forest resources, and produced elaborate pottery, figurines (dogลซ), and lacquerware. Population size remained relatively small for millennia after isolation from the continent (driven by post-glacial sea-level rise). Genetic studies indicate the Jลmon lineage diverged from continental East Asian populations roughly 20,000- 15,000 years ago and maintained a distinct profile until later admixture.
The Jลmon era ended with the arrival of continental influences that inaugurated the Yayoi period (wet- rice agriculture, metallurgy, and new population movements), followed by the Kofun, Nara, and Heian periods that saw the formation of a centralized state and the adoption of writing and Buddhism.โ
This summary draws primarily from the established archaeological and genetic consensus reflected in major reference works and recent ancient- DNA research.
Japanese Paleolithic period (ๆง็ณๅจๆไปฃ, kyลซsekki jidai)
The Japanese Paleolithic is the earliest phase of human occupation of the Japanese archipelago, defined as the pre- pottery period. It is generally dated from roughly 40,000- 36,000 BC (or about 38,000- 40,000 years ago) to around 14,000- 10,000 BC, when pottery appears and the Jลmon period begins.โ
Recent consensus places reliable evidence for modern humans (Homo sapiens) and the Early Upper Paleolithic from approximately 38,000- 36,000 years ago onward. Earlier claims of Lower or Middle Paleolithic occupation (tens or hundreds of thousands of years ago) were largely discredited after a major archaeological scandal.
Chronology and Environment
During cold phases of the Late Pleistocene (especially the Last Glacial Maximum), lower sea levels transformed the geography:
Paleo- Honshu: Honshu, Shikoku, and Kyushu formed a single large island.
Paleo- Hokkaido Peninsula: linked to the Asian continent via Sakhalin.
Expanded Ryukyu Islands.
People were mobile hunter- gatherers who hunted megafauna such as the straight- usked elephant Palaeoloxodon naumanni and the giant deer Sinomegaceros yabei. One key site, Lake Nojiri (Nagano Prefecture), dates to about 37,900 years BP and preserves evidence of butchery of these animals.
Japanโs volcanic soils are highly acidic, so human skeletal remains are extremely rare. Most evidence consists of stone tools. Limited fossils come from Okinawa (e.g., Yamashita Cave ~32,000 years ago; Shiraho Saonetabaru Cave) and a few main- island sites such as Hamakita (Negata) in Shizuoka.
Stone Tool Technology
The Japanese Paleolithic is notable for several distinctive features:
Early appearance of edge- ground and polished stone tools (axes) around 30,000 BC, technology elsewhere associated with the much later Neolithic.
Flake industries with trapezoids and denticulate in the earliest Upper Paleolithic (~39- 37 ka cal BP) on Paleo- Honshu.
Later development of blade technology, knife- shaped tools, and eventually micro blades.
Evidence of trap- pit hunting and possible early use of watercraft.
These assemblages show both local innovation and connections to contemporary industries in China and the Korean Peninsula.โ
Over 10,000- 14,500 Paleolithic sites are now known across the archipelago, one of the densest concentrations in the world, aided by widespread volcanic tephra layers (especially the Aira- Tanzawa tephra) that provide excellent chronological markers.
History of Research and the Fujimura Hoax
Systematic Paleolithic archaeology in Japan began relatively late. The first recognized site was Iwajuku (Gunma Prefecture), discovered by Tadahiro Aizawa in 1946 and excavated in 1949. Before then, excavators typically stopped at Jลmon layers, assuming no earlier occupation.
From the 1970s onward, amateur archaeologist Shinichi Fujimura reported a series of sensational early finds, pushing dates back as far as 600,000 years and establishing an apparent Early and Middle Paleolithic sequence. In November 2000 the newspaper Mainichi Shimbun published photographs of Fujimura burying artifacts at the Kamitakamori site. He later admitted to planting genuine (mostly later) tools at dozens of sites (at least 42 confirmed by the Japanese Archaeological Association).
The scandal invalidated the majority of claimed pre- 40,000- year assemblages and forced a major reassessment. Today only a handful of sites are considered possible candidates for activity before ~40,000 years ago, and the widely accepted start of continuous human presence is placed around 38,000- 35,000 years ago.
Transition to the Jลmon Period
The Paleolithic ends with the appearance of pottery (among the worldโs oldest) around 16,000- 14,000 years ago. This marks the beginning of the Jลmon culture, characterized by greater sedentism, more complex hunter- gatherer adaptations, and the famous cord- marked ceramics.
In summary, the Japanese Paleolithic represents the first successful colonization of the archipelago by modern humans, featuring distinctive early ground-stone technology and a rich, well- dated archaeological record that has been refined through rigorous post- 2000 re- evaluation.
At a campsite in the Paleolithic Period in Japan. Picture painted by Shuichi Hosono, based on the excavation findings at the Tomizawa archaeological site in Miyagi Prefecture. (Courtesy of the Sendai City Board of Education.) Paleolithic Period in Japan – Unfamiliar Japan Tours
Jลmon period (็ธๆๆไปฃ, Jลmon jidai)
The Jลmon period is a major prehistoric era in Japan, lasting approximately from c. 14,000 BC to 300 BC (some chronologies place the start as early as ~16,500- 14,500 years ago with the earliest pottery, and the end as late as ~300โ- 100 BC). It follows the Paleolithic and precedes the Yayoi period.
The name comes from the distinctive โcord- markedโ (jลmon) decoration on pottery, a term coined by American zoologist Edward S. Morse after his 1877 excavation of the ลmori shell mounds near Tokyo.โ
The Jลmon people were primarily sedentary or semi- sedentary hunter -gatherer- fishers who also practiced limited plant cultivation. They achieved a high degree of cultural complexity without full- scale agriculture or metallurgy until the very end of the period. Their society is often described as a sophisticated Mesolithic or early Neolithic culture adapted to Japanโs rich post- glacial environment.
Chronology
The period is conventionally divided into six phases based mainly on pottery typology (with supporting radiocarbon dates).
Approximate ranges (BCE) are:
Phase
Approximate dates
Key characteristics
Incipient
13,750- 8,500
Earliest pottery (among the worldโs oldest); transition from Paleolithic; simple dwellings
Initial
8,500- 5,000
Bullet- shaped pots; first clear settlements and graves
Dates vary slightly by region and source; the Middle phase is widely regarded as the height of Jลmon cultural florescence.
Lifestyle, Settlements, and Economy
People lived in pit dwellings (shallow excavated floors with thatched roofs supported by posts), often arranged around open central spaces. Settlements ranged from small clusters to large villages. One of the most famous is Sannai- Maruyama (Aomori Prefecture, northern Honshu), a major Middle Jลmon hub settlement with large buildings, storage pits, and evidence of long- term occupation.
Subsistence relied on:
Hunting (deer, wild boar; use of bows, arrows, and dogs)
Fishing and shellfish gathering (extensive shell mounds)
Gathering of nuts (chestnuts, walnuts, acorns), roots, and other plants
Limited cultivation of useful plants (e.g., chestnuts, lacquer trees, some beans)
Tools and crafts included polished stone implements, bone and antler tools, lacquerware (among the oldest in the world), baskets, and jewelry. Ritual objects such as clay figurines (dogลซ) are characteristic, especially in later phases.
Pottery
Jลmon pottery is hand- built (coil method), low-fired earthenware and ranks among the earliest ceramics known globally (earliest examples ~14,500- 13,000 BC from sites such as Odai Yamamoto I in Aomori).
Styles evolved from simple pointed- or rounded-bottom vessels to elaborate, highly decorated forms, most famously the ornate โflame- styleโ (kaen- dokฤซ) vessels of the Middle Jลmon. Decoration used cord impressions, shells, sticks, and applied clay.
Archaeology and Key Sites
Systematic study began in the late 19th century. Japan has thousands of Jลmon sites. Notable examples include:
Sannai-Maruyama (Aomori): large Middle Jลmon settlement
ลyu Stone Circles and other ritual sites in the northeast
Shell mounds such as ลmori and Natsushima
Sites in the UNESCO World Heritage โJomon Prehistoric Sites in Northern Japanโ serial property
Northern Japan (Tลhoku and Hokkaido) preserves particularly rich remains due to environmental conditions and later cultural continuity with the Ainu.
Genetics and Origins
Ancient DNA studies show the Jลmon lineage diverged from continental East Asian populations roughly 20,000- 15,000 years ago, coinciding with post-glacial isolation of the archipelago.
They maintained a relatively small effective population size for millennia and show some regional diversity, with later gene flow. Modern Japanese people carry roughly 10% autosomal Jลmon ancestry on average (higher in some regions and among the Ainu). The Jลmon were largely assimilated by incoming Yayoi migrants (associated with rice agriculture and Northeast Asian ancestry) beginning around 900- 300 BC.
End of the Period
The Jลmon era gradually gave way to the Yayoi period with the introduction of wet- rice agriculture, metallurgy, and new population movements from the Korean Peninsula and continent. In some northern areas, Jลmon- derived cultures persisted longer (sometimes called Epi- Jลmon).
The Jลmon period represents one of the longest continuous hunters- gatherer traditions with advanced material culture in the world, lasting roughly 10,000- 14,000 years and leaving a lasting genetic and cultural legacy in Japan.
The Japanese Paleolithic (roughly 40,000/38,000- 14,000 years ago) occurred during the Late Pleistocene, spanning Marine Isotope Stages (MIS) 3 and 2. Climate was generally colder and often drier than today, with significant fluctuations that reshaped landscapes, vegetation, fauna, and human adaptations.
Key Climate Features
Early to middle phase (MIS 3, ~57,000- 29,000 years ago): Relatively warmer and more temperate conditions in places, though cooling overall. Lake Nojiri sediment records show temperate climates supporting megafauna around 53- 37 ka cal BP.
Cooling toward the Last Glacial Maximum (LGM): Gradual cooling from ~38 ka onward.
Last Glacial Maximum (LGM, roughly 26,000- 19,000 years ago, peak ~24- 20 ka): Coldest phase. Mean temperatures were several degrees lower (estimates of 5- 9ยฐC cooler in August depending on region; annual means ~6- 7ยฐC cooler in some southern areas like Okinawa). Precipitation was often reduced, with drier conditions in many areas. Global sea levels dropped by ~120โ140 m.โ
Late Glacial and deglaciation (~18,000- 14,000 years ago):Rapid warming, increased humidity, and major vegetation shifts after ~14- 15 ka.
Volcanic tephra layers and pollen records (e.g., from Lake Nojiri) provide high- resolution proxies for these changes.
Geographic and Environmental Impacts
Lower sea levels created three main landmasses:
Paleo- Honshu (Honshu, Shikoku and Kyushu as one large island).
Paleo- Hokkaido Peninsula (linked to Sakhalin and the Asian continent).
Expanded Ryukyu Islands.
This facilitated some animal migrations earlier in the Pleistocene but required watercraft for initial human arrival during MIS 3-2 (no continuous land bridges to the continent at the time of Homo sapiens colonization).
Vegetation:
Much of the archipelago was dominated by coniferous forests (subarctic/boreal types with Picea, Abies, Tsuga, Pinus).
Northern Hokkaido: parkland and tundra- like conditions.
Temperate broadleaf trees retreated to southern or humid valley refugia.
Abrupt post- LGM shift (~14 ka) from subarctic conifer forests to deciduous broadleaf forests.
Megafauna declined or went extinct around or after the LGM (~26,000 years ago on Paleo-Honshu for some large species), shifting hunting toward medium/small animals (deer, wild boar).
Impacts on Human Populations and Culture
Settlement and mobility: Site numbers increased after ~38 ka with the arrival of modern humans, but declined significantly during the LGM in areas like Lake Nojiri. High-altitude resource areas (e.g., Central Highlands obsidian sources) saw reduced use in the early LGM due to cold conditions.โ
Subsistence: Heavy reliance on hunting in cold, open or coniferous landscapes with limited reliable plant foods (except in the Ryukyus). Post- LGM vegetation change supported greater plant use and set the stage for Jลmon adaptations.
Technology and culture: Lithic industries shifted in response to environmental change, e.g., trapezoids and edge- ground axes early on; backed blades, points, and later micro blades during colder phases. Different strategies developed in open northern landscapes versus forested Paleo-Honshu. Population fluctuations and cultural shifts (e.g., from Early to Middle Upper Paleolithic) correlate with cooling stadial.โ
Overall adaptation: Humans showed flexible responses, adjusting mobility ranges, toolkits, and land use. The cold, unstable climate favored mobile hunter- gatherer lifestyles. Post- LGM warming and forest change coincided with increased activity and the transition to pottery- using Jลmon cultures (~15- 13 ka).
In summary, the cold, fluctuating climate of the Japanese Paleolithic, especially the LGM, drove major landscape restructuring through sea- level drop, forest shifts, and faunal change. These pressures shaped human colonization patterns, technological innovation, population dynamics, and the eventual transition to the more sedentary Jลmon period as conditions warmed.
The Jลmon period (c. 14,000- 300 BC) unfolded during the Holocene, a time of post- glacial warming after the Last Glacial Maximum. Climate was generally warmer and wetter than the preceding Paleolithic, with rising sea levels that fully isolated the Japanese archipelago from the Asian continent. This created rich, diverse ecosystems that supported a long-lasting sedentary hunter- gatherer culture, though fluctuations still drove major cultural and demographic changes.
Key Climate Phases
Early Holocene and Incipient- Initial and Incipient (c. 14,000- 5,000 BC): Rapid warming after the Younger Dryas, with the Bรธlling- Allerรธd and Pre- Boreal warm intervals. Sea levels rose, forming productive coastal environments and shellfish-rich intertidal zones. Broadleaf forests (deciduous nut-bearing trees such as chestnut, oak, and walnut) expanded northward, replacing coniferous forests.
Holocene Climatic Optimum and Early- Middle Jลmon (roughly 9,000- 5,000 BP, peaking in the Middle Jลmon): Warmest and most stable phase. Temperatures were higher than today in many areas, with increased precipitation and strong East Asian summer monsoon influence. This supported peak population density, large settlements, and cultural florescence.
Cooling after the Middle Jลmon (from ~4,500- 4,200 BP onward): Gradual cooling, including the global 4.2 ka event (a significant cool, dry episode). Sea levels fluctuated and sometimes fell slightly. Evergreen forests expanded in the west, while conifers increased in some northern and inland areas. Other shorter Bond events (e.g., 8.2 ka) also caused temporary downturns.โ
Volcanic events (such as the massive Kikai- Akahoya eruption ~7.3 ka) added abrupt local stresses through ash fall and possible short- term cooling.
Environmental Impacts
Sea- level rise created extensive coastlines, lagoons, and shell mounds, boosting marine resources (fish, shellfish).
Forest succession provided abundant plant foods (nuts, chestnuts managed through hansaibai, selective tending), enabling greater sedentism than pure hunting.
Regional differences: Northern Japan (Tลhoku, Hokkaido) remained cooler and more marine-oriented; western Japan saw stronger evergreen forest expansion.
Impacts on Jลmon Society and Culture
Population and settlements: Numbers and size of sites peaked during the warm Middle Jลmon (e.g., the large Sannai- Maruyama settlement in Aomori thrived ~5.9- 4.2 ka under warm conditions that favored chestnut management). Cooling after ~4.2 ka correlated with population decline, abandonment of large โhubโ settlements, and a shift to smaller, more dispersed communities, especially in eastern and northern Japan.โ
Subsistence adaptations: Warmer phases supported intensive plant use, fishing, and limited cultivation. Cooling reduced some terrestrial resources, prompting greater reliance on marine foods, food sharing, and possible dietary stress (e.g., evidence of increased scurvy in some Late Jลmon groups). People managed chestnut and lacquer trees, showing resilience.
Cultural responses: Pottery production expanded with warming and resource abundance. Technological and stylistic changes (projectile points, settlement organization) tracked climatic shifts. In Hokkaido, climate influenced the spread of related cultures through changes in ocean currents and westerlies.
Resilience and limits: Jลmon societies adapted flexibly for millennia through mobility, resource diversification, and social sharing. However, prolonged cooling and resource scarcity contributed to the eventual decline of classic Jลmon patterns and the transition toward Yayoi agriculture and migration.
In short, the post- glacial warming of the Holocene enabled the Jลmonโs remarkable longevity and complexity by creating productive forests and coasts. Yet cooling events, especially the 4.2 ka episode, triggered population reorganization, settlement collapse in some regions, and adaptive shifts that ultimately paved the way for the Yayoi period.
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