Archives de catégorie : climate and geology

climate and geology

New Northern North Atlantic Study Finds The Coldest Period With The Most Sea Ice Of The Last ~85 Years…Is Today

by K. Richard, August 24, 2020 in NoTricksZone

Ecological conditions for 3 temperature- and sea ice-sensitive species show the sub-Arctic North Atlantic has been cooling and gaining ice since 1940.

In recent months, several scientific publications have documented a dramatic cooling trend in the subpolar North Atlantic, with temperatures plummeting 2°C since 2008 (Bryden et al., 2020) or -0.78°C per decade since 2004 (Fröb et al., 2019). Maroon et al. (2020) even point out 2015 was the coldest of the last 100 years.

…

 

…

climate and geology

Fossil leaves show high atmospheric carbon spurred ancient ‘global greening’ Charles Rotter / 3 days ago August 20, 2020

by EARTH INSTITUTE AT COLUMBIA UNIVERSITY, August 20, 2020 in WUWT

Scientists studying leaves from a 23-million-year-old forest have for the first time linked high levels of atmospheric carbon dioxide with increased plant growth, and the hot climate off the time. The finding adds to the understanding of how rising CO2 heats the earth, and how the dynamics of plant life could shift within decades, when CO2 levels may closely mirror those of the distant past.

Scientists retrieved the leaves from a unique onetime New Zealand lake bed that holds the remains of plants, algae, spiders, beetle, flies, fungi and other living things from a warm period known as the early Miocene. Scientists have long postulated that CO2 was high then, and some plants could harvest it more efficiently for photosynthesis. This is the first study to show that those things actually happened in tandem. The findings were published this week in the journal Climate of the Past.

“The amazing thing is that these leaves are basically mummified, so we have their original chemical compositions, and can see all their fine features under a microscope,” said lead author Tammo Reichgelt, an adjunct scientist at Columbia University’s Lamont-Doherty Earth Observatory and assistant professor of geosciences at the University of Connecticut. “Evidence has been building that CO2 was high then, but there have been paradoxes.”

…

 

IMAGE: A 23-MILLION-YEAR-OLD LEAF PRESERVED IN A ONETIME NEW ZEALAND LAKE BED, KEY TO PAST ATMOSPHERIC CONDITIONS. ONE CAN SEE VEINS, GLANDS ALONG THE TEETH, AND HOLES GNAWED BY INSECTS, WITH… view more CREDIT: JENNIFER BANNISTER/UNIVERSITY OF OTAGO

…

better to know...?, climate and geology

VICTORY FOR SCIENCE! German Research Foundation Regrets Censorship, Reinstate’s Critic’s Statement

by P. Gosselin, August 7, 2020 in NoTricksZone

After widespread criticism, the German Research Foundation (DFG) has decided to reverse its July 30th decision to take down a dissident climate science statement from prominent German satirist Dieter Nuhr (background here).

The DFG has put Nuhr’s statement back online again after realizing it had blundered when it caved in to activists and had not acted in the interest of science (pdf here).

…

The German Research Foundation is back, again in favor of diversity of scientific opinion! Image: Galileo fails to change Catholic Church doctrine.

…

climate and geology, climate-debate

Satellite survey shows California’s sinking coastal hotspots

by Arizona State University, August 2, 2020 in WUWT

A majority of the world population lives on low lying lands near the sea, some of which are predicted to submerge by the end of the 21st century due to rising sea levels.

…

The most relevant quantity for assessing the impacts of sea-level change on these communities is the relative sea-level rise – the elevation change between the Earth’s surface height and sea surface height. For an observer standing on the coastland, relative sea-level rise is the net change in the sea level, which also includes the rise and fall of the land beneath observer’s feet.

Now, using precise measurements from state-of-the-art satellite-based interferometric synthetic aperture radar (InSAR) that can detect the land surface rise and fall with millimeter accuracy, an Arizona State University research team has, for the first time, tracked the entire California coast’s vertical land motion.

They’ve identified local hotspots of the sinking coast, in the cities of San Diego, Los Angeles, Santa Cruz and San Francisco, with a combined population of 4 to 8 million people exposed to rapid land subsidence, who will be at a higher flooding risk during the decades ahead of projected sea-level rise.

“We have ushered in a new era of coastal mapping at greater than 1,000 fold higher detail and resolution than ever before,” said Manoochehr Shirzaei, who is the principal investigator of the NASA-funded project. “The unprecedented detail and submillimeter accuracy resolved in our vertical land motion dataset can transform the understanding of natural and anthropogenic changes in relative sea-level and associated hazards.”

The results were published in this week’s issue of Science Advances (DOI link here).

…

climate and geology

Data From 2 Independent Studies Show No Correlation Between CO2 And Temperature

by P. Gosselin, July 29, 2020 in NoTricksZone

German climatologist Professor Dr. Horst-Joachim Lüdecke recently took data from two independent studies and superimposed them. The result shows  the long claimed atmospheric CO2-global temperature correlation doesn’t exist. 

The first data set was global temperature anomaly going back 600 million years, taken from the results of a paper by Came and Veizer, appearing in Nature (2007) and plotted below (blue):

The second data set was of atmospheric CO2 going back 600 million years, taken from a published study by Berner (2003), also appearing in Nature. These data are plotted in the above chart in blue.

No correlation

The plots were combined in the above chart to see how well they correlated, if at all. The result: no correlation.

For example, as the chart shows, 150 million years ago the atmospheric CO2 concentration was over 2000 ppm, which is 5 times today’s atmospheric concentration of 410 ppm – a level that some climate scientists say is already “dangerously high”. Yet, the global temperature 150 million years ago was more than 2°C below the long-term mean.

450 million years ago the relationship was even far more on its head: atmospheric CO2 concentrations were more than 10 times today’s level, yet the global temperature was a frigid 3.5°C below the mean!

“There’s no correlation between earth temperature and CO2,” Prof. Lüdecke concludes, observing recorded data.

better to know...?, climate and geology, climate-debate

More Proof That Geologic Forces Are Melting Thwaites and Pine Island Glaciers

by J.E. Kamis, July 20, 2020 in ClimateChangeDispatch

As previously explained before, increased melting/ice loss of Antarctica’s Pine Island and Thwaites glaciers is the result of geologically induced heat flow emitted from underlying bedrock “hotspots,” not climate change (Figure 1).

All but a very minor amount of Antarctica’s glacial ice melting occurs in the western portion of this continent. The most rapid and greatest ice mass loss areas are in West Antarctica.

They are positioned directly above geographically extensive and high heat flow geological features. This association is thought to be strong evidence of a cause and effect relationship.

Discussion of evidence supporting the contention that the melting of Pine Island and Thwaites glaciers is the result of bedrock heat flow begins with a review of the regional geology (refer to Figure 1).

The Pluton Rich “hotspot” is a 61,000-thousand-square-mile area that is home to numerous high-heat-flow lava pockets that are bounded and fueled by deep earth reaching faults.

Several detailed research studies document the existence and configuration of this area. This lies along the West Antarctic Rift.

The Mount Erebus Volcanic Complex “Hotspot” is the most geologically active portion of Antarctica. It is a 25,000-square-mile high-heat-flow area, much of which is absent of glacial ice.

The absence of glacial ice across a huge portion of West Antarctica is extremely unusual and exceedingly difficult to explain by invoking global warming.

…

Figure 1. NASA map of Antarctica’s ice sheet thickness 1992-2017. Greatest ice thickness losses shaded red. The outline of three regional sub-glacial geological Hotspots” are outlined in red (Image by NASA, most labeling by J. Kamis).

…

climate and geology, climate-debate

Atmospheric CO2 during the Mid-Piacenzian Warm Period and the M2 glaciation

by de la Vega et al., 2020 in Nature OPEN  ACCESS

Abstract

The Piacenzian stage of the Pliocene (2.6 to 3.6 Ma) is the most recent past interval of sustained global warmth with mean global temperatures markedly higher (by ~2–3 °C) than today. Quantifying CO2 levels during the mid-Piacenzian Warm Period (mPWP) provides a means, therefore, to deepen our understanding of Earth System behaviour in a warm climate state. Here we present a new high-resolution record of atmospheric CO2 using the δ11B-pH proxy from 3.35 to 3.15 million years ago (Ma) at a temporal resolution of 1 sample per 3–6 thousand years (kyrs). Our study interval covers both the coolest marine isotope stage of the mPWP, M2 (~3.3 Ma) and the transition into its warmest phase including interglacial KM5c (centered on ~3.205 Ma) which has a similar orbital configuration to present. We find that CO2 ranged from 389+38−8389−8+38ppm to 331+13−11,331−11+13,ppm, with CO2 during the KM5c interglacial being 371+32−29371−29+32ppm (at 95% confidence). Our findings corroborate the idea that changes in atmospheric CO2 levels played a distinct role in climate variability during the mPWP. They also facilitate ongoing data-model comparisons and suggest that, at present rates of human emissions, there will be more CO2 in Earth’s atmosphere by 2025 than at any time in at least the last 3.3 million years.

…

climate and geology

Carbon dioxide level unprecedented in 15 MY… More evidence it’s not the climate control knob!avid Middl

by David Middleton, July 10, 2020 in WUWT

If the Earth was 3-4 °C warmer with a much higher sea level 3.3 million years ago, with about the same CO2 concentration, what does this say about the potency of it as a climate control knob?

The last time CO2 levels were this low, Earth was in the deepest ice age of the Phanerozoic Eon, the Pennsylvanian (Late Carboniferous)-Early Permian.

…

…

Figure 5. Phanerozoic temperatures (pH-corrected) and carbon dioxide. The Miocene is the first epoch of the Neogene Period (Berner et al, 2001 and Royer et al., 2004) (older is toward the left).

…

better to know...?, climate and geology

How Climate Trickery Infiltrated the AGU

by Donna Laframboise, July 2020, In BigPicturesNews

11 presentations – based on private, agenda-driven research – were delivered to the world’s largest gathering of climate scientists.

I’ve been writing about a far-fetched climate fairy tale that was repackaged and re-positioned – with the result that it now gets taken seriously by supposedly serious scientists (see here and here).

How did this happen? First, billionaire climate activists hired consultants to produce a brand new climate analysis. Because, you know, the world doesn’t have enough climate research, what with governments spending billions on it every year.

This custom research was conducted by a team of noticeably young people. One is still working on his doctorate. Two others were doctoral students at the time. The lead scientist had earned his geobiology PhD seven years earlier. The lead economist had earned his, in sustainable development, a mere three years earlier.

This team produced a 2014 report titled Risky Business: The Economic Risks of Climate Change in the United States. It features a graphic that wildly misrepresents the scientific literature.

Six months after that report appeared, fully 11 presentations based on it were delivered at the world’s largest annual gathering of earth scientists – the American Geophysical Union’s December 2014 conference.

…

climate and geology, sciences-general

Mass spectrometry and climate science. Part I: Determining past climates

by Judith Curry, June 16, 2020 in ChRotter_WUWT

Mass spectrometry is essential for research in climate science.

Understanding climate requires having sufficient knowledge about past climate and about the important factors that are influencing climate today, so that reliable models can be developed to predict future climate.

Analytical chemistry enables measurement of the chemical composition of materials, from the amounts of elements and their isotopes in a sample to the identity and concentrations of substances in the most complex biological organisms.

This two-part series covers the application of a powerful analytical chemistry technology — mass spectrometry — to two important areas in climate science:

  • Obtaining reliable information about past climate
  • Understanding composition and behavior of aerosols, which have a large impact on climate

The examples that are included for each topic were selected out of many published papers on the study of climate using mass spectrometry, partly because they feature a very wide range of types of these instruments. The authors were very helpful in providing me with information on their work.[1]

The technology described in this essay may at times be quite complicated! However, I hope that the results of each study will be understandable.

Part 1: Determining past climate

…

…

Figure 1: Age of samples taken at indicated depth below surface of ice core

…

climate and geology, climate-debate

Climate Scientists Step Up the Climate Emergency Narrative

by E. Worrall, June 13, 2020 in WUWT

 

MIP6 Climate Sensitivities. Source Carbon Brief

Guest essay by Eric Worrall

Even worse than we thought ™. Despite a recent sanity test study which demonstrated that high end climate models hindcast impossible Eocene temperatures, climate scientists are pushing ahead anyway with their new, even more extreme climate projections.

 

Continuer la lecture de Climate Scientists Step Up the Climate Emergency Narrative →

climate and geology, only geology

Asteroid, climate change not responsible for mass extinction 215 million years ago

by Todd McLeish, May 27, 2020 U. of RhodeIsland in PhysOrg

A team of University of Rhode Island scientists and statisticians conducted a sophisticated quantitative analysis of a mass extinction that occurred 215 million years ago and found that the cause of the extinction was not an asteroid or climate change, as had previously been believed. Instead, the scientists concluded that the extinction did not occur suddenly or simultaneously, suggesting that the disappearance of a wide variety of species was not linked to any single catastrophic event.

Their research, based on paleontological field work carried out in sediments 227 to 205 million years old in Petrified Forest National Park, Arizona, was published in April in the journal Geology.

..

climate and geology, climate-debate

Arctique géologique, part 2

by Van Vliet-Lanoë B. and Préat A., 29 mai 2020 in ScienceClimatEnergie

4/ Les cycles glaciaires  arctiques (Pliocène/Pléistocène)

4.1. Introduction : le forçage orbital et l’englaciation

Le climat de la Terre est géré à un premier niveau par l’apport énergétique lié à l’apport solaire, en fonction de l’évolution cyclique de la forme de l’orbite de notre planète autour du soleil. Ce forçage s’appelle forçage orbital et a toujours existé depuis que notre système planétaire existe.  Ce forçage présente une cyclicité parfaitement calculable en fonction des interactions par attraction entre les différentes planètes du système solaire et le soleil. Elle varie relativement peu au cours du temps. Par contre, l’orbite terrestre est une ellipse dont l’élongation varie au cours du temps, nous éloignant ou nous rapprochant du soleil, c’est ce que nous appelons l’excentricité.  De plus, l’axe de rotation de la Terre n’est pas vertical sur le plan orbital ou d’écliptique et oscille également, permettant un déficit en énergie reçue au niveau des pôles, géré par son obliquité. Enfin la Terre ne parcourt pas son orbite en exactement un an : les saisons pourront être en avance ou en retard sur l’orbite par rapport au minimum ou au maximum d’insolation : ceci s’appelle la précession des équinoxes.

L’englaciation Cénozoïque débute en position polaire sous contrôle de la tectonique des plaques, de l’évolution des océans, de la circulation océanique et des reliefs orogéniques disponibles pour stocker de la glace. Elle apparaît donc en premier sur l’Antarctique puis au Néogène, sur l’Arctique Canadien en période de faible obliquité. Ensuite, elle descendra en latitude au fur et à mesure de l’évolution de l’ère glaciaire.

…

…

Fig. 24 : LGM ou Last Glacial Maximum, c’est-à-dire la glaciation du ‘Dernier Glaciaire’ dans l’hémisphère nord avec des plateformes de glaces débordant sur l’océan Arctique recouvert de banquise (image CLIMAP). La glace qui recouvrait une grande partie de l’Amérique du Nord, du nord de l’Europe et une partie de l’Asie était épaisse de 3 à 4 km et le niveau marin plus bas de 120 m par rapport à l’Actuel, ce qui permit des passages terrestres, inexistants aujourd’hui suite à la remontée du niveau marin lors de la déglaciation. Cette situation est aussi à l’origine d’une aridification intense (non discutée dans cet article). Les glaces se mirent en place vers 33 ka et leur extension maximale est comprise entre 26,5 ka et 20-19 ka (Clark et al. 2009).

 

…

climate and geology

Study: Ancient ocean oxygen levels associated with changing atmospheric carbon dioxide

by Texas A&M University, May 24, 2020 in WUWT

A Texas A&M-led study analyzed ocean floor sediment cores to provide new insights into the relationship between deep ocean oxygenation and atmospheric carbon dioxide levels in the 50,000 years before the last ice age

IMAGE: Deep ocean floor sediment cores hold chemical clues to Earth’s past. view more  Credit: Texas A&M University

Why do carbon dioxide levels in the atmosphere wax and wane in conjunction with the warm and cold periods of Earth’s past? Scientists have been trying to answer this question for many years, and thanks to chemical clues left in sediment cores extracted from deep in the ocean floor, they are starting to put together the pieces of that puzzle.

Recent research suggests that there was enhanced storage of respired carbon in the deep ocean when levels of atmospheric carbon dioxide concentrations were lower than today’s levels. But new research led by a Texas A&M University scientist has reached back even further, for the first time revealing insights into atmospheric carbon dioxide levels in the 50,000 years before the last ice age.

…

climate and geology

Arctique géologique 1/2

by Préat A. & Van Vliet-Lanoë B., 22 mai 2020 in ScienceClimatEnergie

…

A la grande différence de l’Antarctique, l’Arctique est un océan entouré de plateaux continentaux (Fig. 2). L’océan ou bassin arctique est actuellement constitué par un double bassin, séparé une crête très importante, la ride Lomonosov : le sous-bassin canadien à croûte continentale amincie (3 600 m)  et le sous-bassin eurasiatique à croûte océanique mince, de loin le plus profond (5000 m entre la crête Lomonosov et la ride océanique active de Gakkel). Il est entouré comme le long de l’Atlantique Nord par une plateforme continentale ennoyée, constituée de croûte continentale.  Le bassin arctique  d’abord marin et connecté au Proto-Atlantique au début du Jurassique (voir plus loin), est isolé depuis le Jurassique moyen et essentiellement de nature lacustre, modifiant le régime thermique océanique, amenant un contexte voisin du Glaciaire au Crétacé inférieur (au Valanginien in Dromart et al. 2003 ; Korte et al. 2015 ; Piskarev et al. 2018). Il ne se ré-ouvrira sur le bassin atlantique qu’à partir de l’Eocène, via l’ouverture du détroit de Fram. D’autre part le pôle  magnétique terrestre (Nord) est resté sur le bassin arctique depuis le début du Jurassique, donc en position de déficit énergétique lié à l’obliquité de l’orbite terrestre.

…

Fig. 2  Image Gebco Arctique : L’océan ou bassin arctique est actuellement constitué par un double bassin, séparé une crête très importante, la ride Lomonossov (voir texte).

…

climate and geology

WORLDWIDE VOLCANIC UPTICK — MULTIPLE ERUPTIONS TO 45,000+ FT (13.7+ KM) — DIRECT COOLING EFFECT

by Cap Allon, May 1, 2020 in Electroverse

These past few days have seen a violent worldwide volcanic uptick, sending us all further signs that the next Grand Solar Minimum is dawning.

HIMAWARI-8 (a Japanese weather satellite) recorded two HIGH-LEVEL eruptions on May 16, both occurring in Indonesia.

The first took place at Ibu –a relatively new volcano with only 3 notable eruptions; in 1911, 1998, and 2008– and was confirmed by the Volcanic Ash Advisory Center (VAAC) Darwin which warned of an ash plume rising to an estimated 45,000 ft (13.7 km).

The second high-level eruption took place just a few hours later at Semeru –a very active volcano with an eruptive history peppered with VEI 2s and 3s; the first coming in 1818, the most recent in 2014– and as with Ibu’s, Semeru’s eruption was picked up by both HIMAWARI-8 and the VAAC Darwin, with the latter confirming the generation of “a dark ash plume which reached an altitude of 46,000 ft (14 km).”

In addition, and as recently reported by VolcanoDiscovery.com, active lava flows remain active on the Semeru’s southeast flank, currently about 4,921 ft (1.5 km) long (as of the morning of May 18).

…

https://principia-scientific.org/do-cosmic-rays-trigger-earthquakes-volcanic-eruptions/https://www.researchgate.net/publication/234022172_Explosive_volcanic_eruptions_triggered_by_cosmic_rays_Volcano_as_a_bubble_chamber

climate and geology, climate-debate

L’Antarctique géologique (2/2)

by A. Préat, 1 mai 2020 in ScienceClimatEnergie

Cet article fait suite aux trois récents articles publiés par le Prof. Maurin sur SCE (1/3, 2/3,  3/3), et traite de l’évolution géologique de la plaque Antarctica.
Voir également L’Antarctique géologique (1/2).

3/ Situation récente à l’échelle géologique

3.1. Isolation de la plaque Antarctique

Nous arrivons ainsi à la situation actuelle avec l’Arctique et l’Antarctique, situation décrite dans les parties 1 à 3 des articles de M. Maurin (parties 1/3, 2/3 et 3/3). D’où proviennent les glaciations actuelles ? Pour les comprendre il faut remonter au début de l’ère cénozoïque en considérant l’Antarctique qui était en position polaire (Scotese, 2001).

La plaque antarctique, partie intégrante de l’ensemble des continents formant le Gondwana est entourée dès le Jurassique (Figs. 7 et 12, inL’Antarctique géologique 1/2) de rides médio-océaniques (excepté la péninsule antarctique qui provient d’une limite de plaque convergente active avec failles transformantes séparant la plaque Antarctique et la plaque Scotia). En conséquence, la plaque Antarctique est actuellement en expansion par rapport aux plaques adjacentes, et fut particulièrement stable et isolée par rapport aux événements tectoniques du Mésozoïque et du Cénozoïque (ici).

Dans ce contexte, et en remontant le temps, il faut noter l’individualisation, dès l’Ordovicien, de la péninsule antarctique avec des montagnes de plus de 3200 m d’altitude constituant aujourd’hui la région la plus au nord de l’Antarctique occidental et s’étendant au-delà du cercle polaire. Cette chaîne de montagnes prolonge les Andes de l’Amérique du Sud dans la continuité d’une dorsale sous-marine caractérisée par un gradient géothermique élevé (voir plus loin). Ainsi on voit que l’Antarctique, depuis longtemps et encore aujourd’hui, participe à un jeu de tectonique des plaques encore active avec des effets locaux (notamment variations du  gradient géothermique).Ce gradient géothermique est un élément important à prendre en considération dans la dynamique glaciaire car il favorise la fonte et ensuite le glissement des glaces.

Notons que Arctowski (in Fogg 1992) avait déjà suggéré en 1901 que les Andes étaient présentes dans la pointe nord de la péninsule antarctique (Graham Land) .

3.2. Englacement de la plaque Antarctique

…

Fig. 16 : Image des fonds marins d’une chaîne de 800 km de long de plusieurs volcans actifs de 1000 m de haut situés à proximité de la partie nord du continent antarctique. D’après Kamis, 2016.

…

climate and geology

Three Decades of Mangrove Forest Biomass Change in NSW, Australia

by Lamont et al. , 2020 in CO2Science

Time and again climate alarmists have used computer models to claim that rising CO2 and rising temperatures should be negatively impacting various ecosystems, including forests. Given that these two parameters have supposedly reached unprecedented heights in modern history, reason suggests that this hypothesis of ecosystem decline should be presently evident in observational data. But is it?

Thanks to the work of Lamont et al. (2020) this question can be answered — at least for a mangrove forest ecosystem in New South Wales, Australia.

What the five Australian researchers did in their study was to examine the biomass change of two mangrove forest sites over the period 1989-2018. The two sites included a tall gallery forest composed of Avicennia marina (i.e., Site 1) and an interior, higher elevation, stunted mixed community of A. marina and Aegiceras corniculatum (i.e., Site 2). Data originally gathered in a 1989 survey were compared with new data obtained by Lamont et al. in 2018 and thereafter analyzed for possible trends.

Results of the analysis are summarized in the figure below, showing large gains in both aboveground and below ground biomass between the two survey dates at both mangrove forest sites. Of particular note is “a greater than seven-fold increase in mean aboveground biomass” at Site 2, and “a six-fold and 12-fold increase [in total below-ground root mass] at Site 1 and Site 2, respectively.” Such large biomass increases, not surprisingly, were estimated by the authors to have contributed to large gains in carbon sequestration. In extrapolating such gains to the entire New South Wales region, they estimate mangrove forests have sequestered “at least about 1.8 Tg C” over the past 70 years.

The above findings represent incredible growth benefits reaped by mangrove forest ecosystems during a time of rising atmospheric CO2 and rising temperature, which findings are pretty much the opposite of the doom and gloom predictions offered by climate alarmists.

…

climate and geology

L’Antarctique géologique (1/2)

by A. Préat, 24 avril 2020 in ScienceClimatEnergie

Cet article traite de l’évolution géologique de la plaque Antarctica, et fait suite aux trois récents articles publiés dans SCE par le Prof. Maurin sur la cryosphère actuelle (1/3, 2/3,  3/3).

1/ Les glaces fascinent …

Les glaces fascinent depuis longtemps les climatologues qui y voient un monde à part, aujourd’hui elles sont suivies ‘à la loupe’ car elles témoigneraient en tout ou en partie du processus de réchauffement actuel. Elles sont l’objet d’une attention médiatique constante. Pourtant elles furent souvent absentes de la Planète, elles apparurent plusieurs fois et disparurent autant de fois au cours de l’histoire géologique, le plus souvent suivant des modalités différentes à l’échelle temporelle et spatiale.

Il n’est pas possible ici de retracer la longue histoire des glaces qui commence au Précambrien, au moins à la transition Archéen et Protérozoïque (avec la glaciation huronienne, il y a environ 2,4 Ga, pour l’échelle détaillée des temps géologiques voir ici, et ci-dessous (Fig. 1) pour une version simplifiée) et se poursuit avec des aléas divers avec un recouvrement des glaces sur l’ensemble de la Planète à la fin du Néoprotérozoïque, donc y compris dans la zone équatoriale, donnant lieu au fameux ‘Snowball Earth’ ou hypothèse de la Terre boule de neige ou encore ‘Terre gelée’ (glaciation marinoenne qui a fait suite à la -ou les ? glaciation(s) sturtienne(s)- il y a 635 Ma. Ensuite viendra la glaciation Gaskiers vers 580 Ma, c’est-à-dire vers la fin du Précambrien. Cet épisode marinoen d’englacement généralisé perdura plus d’une dizaine de millions d’années avec des calottes de glace sur l’équateur (ici) et est à l’origine du nom de l’avant-dernière période du Précambrien, à savoir le Cryogénien (partie supérieure du Protérozoïque entre 850 Ma et 635 Ma, cf. Fig. 1). Entre ces deux grandes glaciations précambriennes (celles de l’huronien et du marinoen), soit sur un peu plus de 1,5 Ga  aucune autre glaciation n’a encore? été rapportée, ce qui supposerait que pendant cet intervalle de temps le climat s’est maintenu dans des conditions plutôt chaudes, avec une régulation thermique ‘sans faille’ (Ramstein, 2015). Notons également pour être complet la présence de glaciers locaux à 2,9 Ga dans l’Archéen d’Afrique du Sud (glaciation ‘pongolienne’) (ici).

…

climate and geology, climate-debate

Magma Flood Linked To Sudden Ancient Global Warming Event

by H. Lee, April 1, 2020 in ClimateChangeDispatch

A study has cemented the link between an intense global warming episode 56 million years ago and volcanism in the North Atlantic, with implications for modern climate change.

Roughly 60 million years ago, circulation changes deep within our planet generated a hot current of rock — the Iceland plume — causing it to rise from the heart of Earth’s mantle.

…

…

 

The Giant’s Causeway in Northern Ireland is a geologic feature consisting of thousands of interlocking basalt columns that formed from volcanic eruptions 60 million years ago.

The Wrong Kind Of Carbon

Although a great deal of North Atlantic volcanism happened close in time to the PETM, scientists were initially skeptical that it could have driven the warming.

Sedimentary layers that formed at the time had the wrong kind of carbon — they were rich in the isotope carbon-12, indicating an organic carbon source rather than a volcanic one.

The leading theory was that fluctuations in Earth’s orbit around the sun melted a type of frozen methane just beneath the seabed called methane clathrates.

Yet scientists found scant evidence that enough clathrates existed in the pre-PETM world, or that they could have melted fast enough to drive the warming.

A possible missing link between the North Atlantic Igneous Province and organic carbon was spotted in 2004 in seismic scans through the seabed off the coast of Norway.

Continuer la lecture de Magma Flood Linked To Sudden Ancient Global Warming Event →

climate and geology

Australian fires: Climate ‘truth bomb’?

by Alan Longhurst, February 24, 2020 in WUWT

Recipe for Australia’s climate ‘truth bomb’:  dubious manipulations of the historical temperature record, ignorance of the climate dynamics of the Southern Hemisphere, and ignorance of Australia’s ecological and social history.

A correspondent of The Guardian newspaper writes that her personal ‘climate truth bomb’ hit her while she was picking ash from her glass at a wine tasting event – the Sydney Harbour bridge being dimly seen through the murk of bushfires. The truth came to her, she wrote, in the eloquent rage of Greta Thunberg and also in heat, smoke and fire.

Although anthropogenic climate change sells well, especially at The Guardian, their Sydney correspondent cannot be so ignorant about the climate of Australia or about bushfires as she pretends. Put briefly, bushfires in Australia and elsewhere have two main sources: from thunderstorms or from human activity, deliberate or otherwise – cigarette butts, sparks from brakes on railway trains, from incautious welding on farm machinery and from electric transmission lines. In California, where almost 2 million acres burned in 2018 and claimed many lives, the electricity supply company now closes down its transmission lines in windy conditions to prevent sparking and fires.

As she should have known, climate change or not, that ash in The Guardian correspondent’s wine was very probably caused by the direct action of an Australian citizen. In the current drought, 36% of fires have been judged to be accidental, 37% as suspicious, 13% as deliberate and only 6% as natural. And that pattern is not new: Australia has a serious arson problem. “In short, up to 85 bushfires begin every day because someone leaves their house and decides to start one,” said Dr. P. Reid of the Australian Center for Research in Bushfires and Arson

…

climate and geology, climate-debate

Thwaites Glacier: Why Did The BBC Fail To Mention The Volcanoes Underneath?

by D. Whitehouse, January 29, 2020 in GWPF

Scientists have known for years that subglacial volcanoes and other geothermal “hotspots” are contributing to the melting of the Thwaites Glacier. Why did the BBC fail to mention these facts in its recent report?

 

The International Thwaites Glacier Collaboration is performing some magnificent science, conducting the most ambitious fieldwork ever undertaken at the tip of what is one of the most significant glaciers on Earth. Its melting already contributes 4% of global sea level rise and there are fears that it could become unstable and contribute many metres to global sea level.

The reason for its vulnerability lies in its geology. While most of the glacier is on ground and making its way into the West Antarctic seas, Thwaites lip floats on water allowing warm water to weaken and melt it from beneath. Being one of the most difficult places in the world to reach the scientific collaboration planned for years to transport many tonnes of equipment to the glaciers front. Two weeks ago they announced they had carried out the first warm water borehole through the ice at the point where it lifts off the land and starts to be suspended by the ocean. Image courtesy British Antarctic Survey.

…

climate and geology

Why The Current Interglacial Might Be Coming To An End

by W. Jones, January 22, 2020 in ClimateChangeDispatch

Did you know that over the last 450,000 years there have been four Ice Ages lasting around 100,000 years each?

And five interglacial periods lasting around 12,000 years each?

Look at this graph of temperature data derived from the Vostok ice core from Antarctica.

 

What it means is that for around 90 percent of the last 450,000 years Earth has been in an Ice Age, where global temperatures have slumped to as low as 10 deg C colder than in the relatively brief interglacial periods.

The current interglacial period (the fifth) began about 11,600 years ago, suggesting it may not last much longer. It corresponds to the time when human beings began farming and building cities and civilizations.

It is notably cooler than the previous four interglacial periods. If we ‘zoom in’ on it (see the upper graph, below)

…

climate and geology

Des réchauffements répétitifs sans CO2 ?

by P. Berth & A. Préat, 24 janvier 2020 in ScienceClimatEnergie

Depuis le début des mesures thermométriques directes, les 4 principales séries de température  que nous possédons (thermomètres terrestres et satellites) nous montrent que la température globale de la basse troposphère a augmenté de ± 0,8°C en 138 ans (entre 1880 et 2018). Cela correspond à ± 0,28°C en 50 ans soit 0,006°C/an(actuellement environ 0,01°C/an pour les 30 dernières années). Les médias nous rappellent chaque jour que cette hausse est exceptionnelle et que le CO2 anthropique en est à l’origine, c’est-à-dire est le grand coupable suivant la terminologie consacrée.

Mais cette vitesse d’augmentation de la température, est-elle vraiment exceptionnelle? Dans les lignes qui suivent, nous allons vous démontrer qu’il n’en est rien. Au cours de la dernière période glaciaire, alors que l’espèce humaine existait déjà, la température moyenne a parfois augmenté à une vitesse vingt fois plus élevée, et ce à de nombreuses reprises. Ces phénomènes particuliers, qui n’ont pas fait disparaître la vie sur Terre, et que nous vous avions déjà mentionnés sur SCE (ici), sont appelés évènements de Dansgaard-Oeschger ou ‘DO’ (des noms des deux scientifiques -danois et suisse-  qui furent les premiers à les mettre en évidence) et sont reconnus par le GIEC. Comme nous allons vous le montrer dans le présent article, le taux de CO2 n’aurait qu’un rôle mineur dans ces évènements.

Figure 1. Stratigraphie isotopique de l’oxygène à partir des glaces du forage GRIP (Groenland).
En ordonnée valeurs du δ18O en ‰ et en abscisse profondeur en mètres du forage (Cronin, 2010). Les compositions isotopiques de l’oxygène sont un indicateur de la température. La figure montre de manière très claire que l’interglaciaire actuel (Holocène, moitié gauche du graphique) est caractérisé par des fluctuations thermiques de faible amplitude (si l’on excepté un épisode plus froid vers 8,2 ka) alors que le Dernier Glaciaire (moitié droite du graphique) montre des changements climatiques fréquents, rapides et de grandes amplitudes (de 8°C à 16°C suivant les δ18O) enregistrés pas les événements ou ‘cycles’ DO (Dansgaard-Oeschger events). Nb: YD pour Younger Dryas, correspondant à un refroidissement il y a 12800 ans BP (non discuté dans cet article).

…

 

climate and geology

YOUNGER DRYAS — REWIND AND REPEAT

by Poppaloff, January 10, 2020 in Electroverse

If the historical data is anything to go by, magnetic reversals/excursions often lead to large-level extinction events. Mounting evidence also suggests that our sun micro-novas every 12,000 years, or thereabouts, and that these two events are linked. Earth’s temperature has been on a downward trend since the sharp-warming that followed the end of the Younger Dryas, indicating that this coming Grand Solar Minimum could steer us back into a major glaciation period, and another extinction event.

In their 2014 paper, a group of scientists which included UC Santa Barbara’s James Kennett, posited that a comet collision with Earth played a major role in the extinction. Their hypothesis suggests that a cosmic-impact-event caused the Younger Dryas period of global cooling close to 12,800 years ago. This cosmic impact resulted in abrupt environmental stress and degradation that contributed to the extinction of most large animal species then inhabiting the Americas. According to Kennett, the catastrophic impact and the subsequent climate change also led to the disappearance of the prehistoric Clovis culture, known for its big game hunting, and to human population decline.

…

 

…