Archives par mot-clé : Geology

Molecular fossils from phytoplankton reveal secular Pco2 trend over the Phanerozoic

by C.R. Witkowski et al., November28,  2018 in SciAdvances


Here, we reconstructed Phanerozoic PCO2 from a single proxy: the stable carbon isotopic fractionation associated with photosynthesis (Ɛp) that increases as PCO2 increases. This concept has been widely applied to alkenones, but here, we expand this concept both spatially and temporally by applying it to all marine phytoplankton via a diagenetic product of chlorophyll, phytane. We obtained data from 306 marine sediments and oils, which showed that Ɛp ranges from 11 to 24‰, agreeing with the observed range of maximum fractionation of Rubisco (i.e., 25 to 28‰). The observed secular PCO2 trend derived from phytane-based Ɛp mirrors the available compilations of PCO2over the past 420 Ma, except for two periods in which our higher estimates agree with the warm climate during those time periods. Our record currently provides the longest secular trend in PCO2 based on a single marine proxy, covering the past 500 Ma of Earth history

Fig. 2Ɛp calculated from phytane in Witkowski et al., 2018

See also here

Climate, life and the movement of continents: New connections

by University of Texas at Austin, November 15, 2018 in ScienceDaily


A new study by The University of Texas at Austin has demonstrated a possible link between life on Earth and the movement of continents. The findings show that sediment, which is often composed of pieces of dead organisms, could play a key role in determining the speed of continental drift. In addition to challenging existing ideas about how plates interact, the findings are important because they describe potential feedback mechanisms between tectonic movement, climate and life on Earth.

The study, published Nov. 15 in Earth and Planetary Science Letters, describes how sediment moving under or subducting beneath tectonic plates could regulate the movement of the plates and may even play a role in the rapid rise of mountain ranges and growth of continental crust


 

Paleoclimatological Context and Reference Level of the 2°C and 1.5°C Paris Agreement Long-Term Temperature Limits

by S. Lüning & F. Vahrenholt, December12, 2017 in FrontEarthSci


The Paris Agreement adopted in December 2015 during the COP21 conference stipulates that the increase in the global average temperature is to be kept well below 2°C above “pre-industrial levels” and that efforts are pursued to limit the temperature increase to 1.5°C above “pre-industrial levels.” In order to further increase public acceptance of these limits it is important to transparently place the target levels and their baselines in a paleoclimatic context of the past 150,000 years (Last Interglacial, LIG) and in particular of the last 10,000 years (Holocene; Present Interglacial, PIG). Intense paleoclimatological research of the past decade has firmed up that pre-industrial temperatures have been highly variable which needs to be reflected in the pre-industrial climate baseline definitions …

See also here

500 Million Years of Unrelatedness between Atmospheric CO2 and Temperature

by Davis W.J., 2017 in CO2Science


Davis, W.J. 2017. The relationship between atmospheric carbon dioxide concentration and global temperature for the last 425 million years. Climate 5: 76; doi: 10.3390/cli5040076.

Writing by way of introduction to his work, Davis (2017) notes that “a central question for contemporary climate policy is how much of the observed global warming is attributable to the accumulation of atmospheric CO2 and other trace greenhouse gases emitted by human activities.” If you talk to a climate alarmist, the answer you receive from such an inquiry will likely be “almost all.” A climate skeptic, on the other hand, will likely respond that the answer is “likely none.”

Hoping to provide some crucial information on this topic, Davis analyzed the relationship between historic temperature and atmospheric CO2 using the most comprehensive assemblage of empirical databases of these two variables available for the Phanerozoic period (522 to 0 million years before present; Mybp). In all, 6680 proxy temperature and 831 proxy CO2 measurements were utilized, enabling what Davis described as “the most accurate quantitative empirical evaluation to date of the relationship between atmospheric CO2concentration and temperature.” Multiple statistical procedures and analyses were applied to the proxy records and the resultant relationship is depicted in the figure below.

Egalement voir ici

Geologists: No Link Between Climate Warming And Rock Slides in European Alps!

by P. Gosselin, September 23, 2018 in NoTricksZone


Last year, August, 2017, a massive rockslide occurred on the north flank of the Piz Cengalo (3369 m) in the Swiss Alps, above the village of Bondo, located near the border to Italy.

No data suggesting warming is behind rock slides

In total some 4 million tonnes of rock and mud came tumbling down. The dramatic incident highlighted the hazards posed by rock slides for villages located near the picturesque mountains of the European Alps.

Though rockslides are not unusual, there has been growing scrutiny behind their causes lately. Unsurprisingly climate alarmists are opportunistically pointing the finger at climate warming.

 

 

A Geological Feud Over the Meghalayan? Or Just More Rubbish Published by the American Association for the Advancement of Science of America?

by David Middleton, September 24, 2018 in WUWT


Alternate Title: Yes, We Have No Anthropocene, We Have No Anthropocene Today! (Sung to the tune of Yes, We Have No Bananas)

 

Figure 4 from Finney & Edwards.  “Workflow for approval and ratification of a Global Standard Stratotype Section and Point (GSSP) proposal. Extensive discussion and evaluation occurs at the level of the working group, subcommission, and International Commission on Stratigraphy (ICS) Bureau. If approved at these successive levels, a proposal is forwarded to the International Union of Geological Sciences (IUGS) for ratification. This process is also followed for other ICS decisions on standardization, such as approval of names of formal units, of revisions to the units, and to revision or replacement of GSSPs.”

500 Million Years of Unrelatedness between Atmospheric CO2 and Temperature

by Davis W.J., 2017 in Climate/CO2Science


One final gem from Davis’ work is a pronouncement that follows a discussion on the lack of correlation between CO2 and temperature across the historical record, where he aptly reminds us that “correlation does not imply causality, but the absence of correlation proves conclusively the absence of causality.” Consequently, there should be no more doubt regarding the ineffectiveness of atmospheric CO2 to control or drive climate change. It is simply nothing more than a bit player, whose influence has been continually overestimated by climate alarmists. The big question now is whether or not 500 million years of these data will convince them otherwise!

from Davis 2017

Egalement: Le changement climatique : la règle en géologie

Highlights From the 2018 BP Statistical Review of World Energy

by David Middleton, September 12, 2018 in WUWT


Statistical Review of World Energy

Global primary energy consumption grew strongly in 2017, led by natural gas and renewables, with coal’s share of the energy mix continuing to decline

Energy developments

  • Primary energy consumption growth averaged 2.2% in 2017, up from 1.2 % last year and the fastest since 2013. This compares with the 10-year average of 1.7% per year.
  • By fuel, natural gas accounted for the largest increment in energy consumption, followed by renewables and then oil.
  • Energy consumption rose by 3.1% in China. China was the largest growth market for energy for the 17th consecutive year.

Carbon emissions

  • Carbon emissions increased by 1.6%, after little or no growth for the three years from 2014 to 2016.

[…]

BP

Despite the Never-Ending Death of Coal: It’s Still a Fossil Fueled World

Out with the Anthropocene – in with the Meghalayan

by Anthony Watts, September 11, 2018 in WUWT


WUWT readers may recall that climate activists wanted the current epoch we live in to be named the “Anthropocene”, because they believe humans are the dominate force on the planet. The official organization that decides such things, The International Commission on Stratigraphy, would have none of it, and nixed the naming recently. Now, here’s a summary of the the Meghalayan.


Welcome to the new Meghalayan age – here’s how it fits with the rest of Earth’s geologic history

Steve Petsch

Associate Professor of Geosciences, University of Massachusetts Amherst

Jurassic, Pleistocene, Precambrian. The named times in Earth’s history might inspire mental images of dinosaurs, trilobites or other enigmatic animals unlike anything in our modern world.

….

10 New Reconstructions Show Today’s Temperatures Still Among The Coldest Of The Last 10,000 Years

by K. Richard, September 10, 2018 in NoTricksZone


Even though CO2 concentrations hovered well below 300 ppm throughout most of the Holocene, newly published paleoclimate reconstructions affirm that today’s surface temperatures are only slightly warmer (if at all) than the coldest periods of the last 10,000 years.  This contradicts the perspective that temperatures rise in concert with CO2 concentrations.

 

Bottom Graph Source: Rosenthal et al. (2013)

Climatariat News Network: Interior Secretary Ryan Zinke isn’t a geologist because climate change.

by D. Middelton, September 8, 2018 in WUWT


Guest CNN-bashing by David Middleton (a geologist)

ran across this April 2018 article while looking for something else.  I totally missed this episode of Trump Derangement Syndrome.

Secretary Zinke’s stance on climate change is one of several reasons the Climatariat News Network decided that he was being dishonest in describing himself as a geologist…

A Second Letter to the Geological Society

by Andy May, August 29, 2018 in WUWT


In June of this year, Howard Dewhirst, a fellow of The Geological Society (London), wrote a letter to the President of the Society voicing the concern of 33 current and former fellows of the society, as well as other concerned geoscientists, that the Society’s position on climate change is outdated and one-sided. As of this writing, receipt of the letter has been acknowledged, but no reply has been received. Given the long period of time, Howard has sent a second letter to the Society, it is reproduced below.

Dear President

We understand that the council is reviewing the The Geological Society’s 2010 and 2013 position papers on climate change which was the subject of the letter we wrote to the society in early June. We also understand that despite the clear interest amongst Fellows – and other scientists, that the society will not be publishing further letters until the new position paper has been agreed. If true, we (the contributors to the first letter) think this is unfortunate, as now would be the very time to solicit informed opinion from Fellows and others as there clearly is not a consensus. …

Geologists uncover new clues about largest mass extinction ever

by University of Tennessee at Knoxville, August 27, 2018 in ScienceDaily from Nature.


Through the analysis of samples, Broadley and his team tried to determine the composition of the lithosphere. They found that before the Siberian Flood Basalts took place, the Siberian lithosphere was heavily loaded with chlorine, bromine, and iodine, all chemical elements from the halogen group. However, these elements seem to have disappeared after the volcanic eruption.

“We concluded that the large reservoir of halogens that was stored in the Siberian lithosphere was sent into the earth’s atmosphere during the volcanic explosion, effectively destroying the ozone layer at the time and contributing to the mass extinction,” Broadley said.

Integrated genomic and fossil evidence illuminates life’s early evolution and eukaryote origin

by Holly C. Betts et al., August 20, 2018 in NatureEcology&Evolution


We derive a timescale of life, combining a reappraisal of the fossil material with new molecular clock analyses. We find the last universal common ancestor of cellular life to have predated the end of late heavy bombardment (>3.9 billion years ago (Ga)). The crown clades of the two primary divisions of life, Eubacteria and Archaebacteria, emerged much later (<3.4 Ga), relegating the oldest fossil evidence for life to their stem lineages. The Great Oxidation Event significantly predates the origin of modern Cyanobacteria, indicating that oxygenic photosynthesis evolved within the cyanobacterial stem lineage. Modern eukaryotes do not constitute a primary lineage of life and emerged late in Earth’s history (<1.84 Ga), falsifying the hypothesis that the Great Oxidation Event facilitated their radiation…

Chemical nature of the 3.4 Ga Strelley Pool microfossils

by J. Allen et al., 2018 in GeochemicalPerspectiveLetters


The biogenicity of putative traces of life found in early-Archean rocks is strongly debated. To date, only equivocal lines of evidence have been reported, which has prevented a full consensus from emerging. Here we report elemental and molecular data from individual organic microfossils preserved within the 3.4 billion-year-old cherts of the Strelley Pool Formation, Western Australia. The present results support the growing body of evidence advocating their biogenicity, promoting them as the oldest known authentic organic microfossils. These microfossils consist of nitrogen- and oxygen- rich organic molecules that have been only slightly degraded despite experiencing temperatures of ~300 °C. Such molecular preservation emphasises the palaeobiological potential of the Earth’s oldest geological record, whilst providing a promising window into the early biosphere.

See also here