California Megaflood: Lessons from a Forgotten Catastrophe

by B. Lynn Ingram, January 1, 2013


 43-day storm that began in December 1861 put central and southern California underwater for up to six months, and it could happen again

Geologic evidence shows that truly massive floods, caused by rainfall alone, have occurred in California every 100 to 200 years. Such floods are likely caused by atmospheric rivers: narrow bands of water vapor about a mile above the ocean that extend for thousands of kilometers.

Vision, not limbs, led fish onto land 385 million years ago

through ScienceDaily, March 7, 2017

A new study suggests it was the power of the eyes and not the limbs that first led our aquatic ancestors to make the leap from water to land. The researchers discovered that eyes nearly tripled in size before — not after — the water-to-land transition. Crocodile-like animals saw easy meals on land and then evolved limbs that enabled them to get there, the researchers argue.

Timing of global regression and microbial bloom linked with the Permian-Triassic boundary mass extinction: implications for driving mechanisms

by Björn Baresel et al., March 6, 2017, Nature


Since the early days of stratigraphy, mass extinctions were noticed to coincide with major and global sea-level changes1,2 that significantly alter extinction patterns and time-series of geochemical proxies. In the case of the Permian-Triassic boundary mass extinction (PTBME), the system boundary itself has been initially placed during a global eustatic regression3, but was subsequently placed during a global transgression4 …

Shock finding : P-T mass extinction was due to an ice age, and not to warming

Geologic Evidence of Recurring Climate Cycles and Their Implications for the Cause of Global Climate Changes. The Past is the Key to the Future

Don J. Easterbrook, 2011

Department of Geology, Western Washington University, Bellingham, WA 98225, USA


Temperatures have risen approximately a degree or so per century since the coldest part of the Little Ice Age ~500 years ago, but the rise has not been linear. Global temperatures have warmed and cooled many times in 25-35-year cycles, well before the atmospheric CO2 began to rise significantly.

Two episodes of global warming and two episodes of global cooling occurred during the 20th century (Fig. 1). Overall, temperatures during the century rose about the same as the rate of warming per century since the Little Ice Age 500 years ago.

World’s oldest fossils unearthed

by University College London, March 1, 2017


Remains of microorganisms at least 3,770 million years old have been discovered by an international team led by UCL scientists, providing direct evidence of one of the oldest life forms on Earth.

Tiny filaments and tubes formed by bacteria that lived on iron were found encased in quartz layers in the Nuvvuagittuq Supracrustal Belt (NSB), Quebec, Canada.

The NSB contains some of the oldest sedimentary rocks known on Earth which likely formed part of an iron-rich deep-sea hydrothermal vent system that provided a habitat for Earth’s first life forms between 3,770 and 4,300 million years ago …

Scrutinizing the carbon cycle and CO2 residence time in the atmosphere

by Hermann Harde, Global and Planetary Change, 24 February 2017


Highlights

An alternative carbon cycle is presented in agreement with the carbon 14 decay.

The CO2 uptake rate scales proportional to the COconcentration.

Temperature dependent natural emission and absorption rates are considered.

The average residence time of CO2 in the atmosphere is found to be 4 years.

Paleoclimatic CO2 variations and the actual CO2 growth rate are well-reproduced.

The anthropogenic fraction of CO2 in the atmosphere is only 4.3%.

Human emissions only contribute 15% to the CO2 increase over the Industrial Era.

Also this link

Diamond’s 2-billion-year growth charts tectonic shift in early Earth’s carbon cycle

Science Daily, February 23, 2017


A study of tiny mineral ‘inclusions’ within diamonds from Botswana has shown that diamond crystals can take billions of years to grow. One diamond was found to contain silicate material that formed 2.3 billion years ago in its interior and a 250 million-year-old garnet crystal towards its outer rim, the largest age range ever detected in a single specimen. Analysis of the inclusions also suggests that the way that carbon is exchanged and deposited between the atmosphere, biosphere, oceans and geosphere may have changed significantly over the past 2.5 billion years.

S. Timmerman, J.M. Koornneef, I.L. Chinn, G.R. Davies. Dated eclogitic diamond growth zones reveal variable recycling of crustal carbon through timeEarth and Planetary Science Letters, 2017; 463: 178 DOI: 10.1016/j.epsl.2017.02.001

Baffin Bay and Kane Basin polar bears not ‘declining’ concludes new report

by Polar Bear Science, February 15, 2017


The 2016 Scientific Working Group report on Baffin Bay and Kane Basin polar bears was released online without fanfare last week, confirming what local Inuit have been saying for years: contrary to the assertions of Polar Bear Specialist Group scientists, Baffin Bay and Kane Basin subpopulations have not been declining but are stable.

Combien y a-t-il de continents sur Terre ? 7 avec Zealandia !

par Christophe Magdelaine, 20 février 2017


Savez-vous combien y a-t-il de continents sur Terre ? 5 ou 6 ? Alors que la question divise encore certaines personnes, un nouveau continent caché en partie sous l'océan Pacifique vient d'être confirmé par une équipe de scientifiques après des dizaines d'années de recherche. Le 7e continent : Zealandia est maintenant officiellement reconnu.
Source : notre-planete.info, http://www.notre-planete.info/actualites/4586-nombre-continents-Terre-Zealandia

Climate models for the layman

by Judith Curry, Feb 2017


Professor Judith A. Curry is the author of over 180 scienti c papers on weather and climate and is a recipient of the Henry G. Houghton Research Award from the Amer- ican Meteorological Society in 1992. She recently retired from the Georgia Institute of Technology, where she held the positions of Professor and Chair of the School of Earth and Atmospheric Sciences. She is currently President of Climate Forecast Appli- cations Network.

Oil – Where did it come from?

by David Middleton, petroleum geologist/geophysicist,  February 18, 2017


As the biomass is buried more deeply in the sedimentary column, increasing pressure compacts it, increasing temperature cooks it and over time, the hydrocarbons slowly migrate toward the surface because they are less dense than connate/formation water. The kerogen first cooks to heavy oil, then light oil, then wet thermogenic gas, then thermogenic light gas, then high temperature methane…

Oil – Will we run out?

By Andy May, February 17, 2017


In November, 2016 the USGS (United States Geological Survey) reported their assessment of the recent discovery of 20 billion barrels of oil equivalent (technically recoverable) in the Midland Basin of West Texas. About the same time IHS researcher Peter Blomquist published an estimate of 35 billion barrels. Compare these estimates with Ghawar Field in Saudi Arabia, the largest conventional oil field in the world, which contained 80 billion barrels when discovered. There is an old saying in the oil and gas exploration business “big discoveries get bigger and small discoveries get smaller.” …

Scientists uncover huge reservoir of melting carbon under Western United States

by Saswata Hier-Majumder et al., February 2017

Pervasive upper mantle melting beneath the western US, Earth and Planetary Science Letters (2017). DOI: 10.1016/j.epsl.2016.12.041


New research published in Earth and Planetary Science Letters describes how scientists have used the world’s largest array of seismic sensors to map a deep-Earth area of melting carbon covering 1.8 million square kilometres. Situated under the Western US, 350km beneath the Earth’s surface, the discovered melting region challenges accepted understanding of how much carbon the Earth contains – much more than previously understood …
Read more at: https://phys.org/news/2017-02-scientists-uncover-huge-reservoir-carbon.html#jCp

Le sol, un héritage méprisé

par Ales Bartos, 16 février 2017


Étant très marginalisées sur le champ médiatique, les problématiques liées aux sols échappent largement à l'attention du public. Pourtant, la pollution et l'érosion des sols fait annuellement baisser la capacité des sols de produire des aliments en qualité et quantité suffisantes pour nourrir une population mondiale croissante. Cet article tente d'ouvrir des pistes vers une meilleure gestion des sols, physique et réglementaire, s'inscrivant dans les logiques du développement durable.
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Atlantique Nord : le risque d’un refroidissement rapide au XXIe siècle revu à la hausse

par D. Swingedouw et al., CNRS, 15 février 2017


Dans le cadre du projet européen EMBRACE, une équipe d’océanographes a réexaminé ces 40 projections climatiques en se focalisant sur un point névralgique au nord-ouest de l’Atlantique Nord : la mer du Labrador. Cette mer est le siège d’un phénomène de convection, qui nourrit à plus grande échelle la circulation océanique de retournement. Ses eaux de surface se refroidissent fortement en hiver, deviennent plus denses que les eaux de profondeur et plongent vers le fond. La chaleur des eaux profondes est transférée vers la surface et empêche la formation de banquise

Eocene global warming events driven by ventilation of oceanic dissolved organic carbon

by Ph.F. Sexton et al., Nature, 2011


‘Hyperthermals’ are intervals of rapid, pronounced global warming known from six episodes within the Palaeocene and Eocene epochs (~65–34million years (Myr) ago)12345678910111213. The most extreme hyperthermal was the ~170 thousand year (kyr) interval2 of 5–7°C global warming3 during the Palaeocene–Eocene Thermal Maximum (PETM, 56Myr ago). The PETM is widely attributed to massive release of greenhouse gases from buried sedimentary carbon reservoirs1361114151617, and other, comparatively modest, hyperthermals have also been linked to the release of sedimentary carbon36111617

Egalement, une synthèse en français

Current Surface Mass Budget of the Greenland Ice Sheet

Danish Meteorological Institute (DMI), February 2017


Greenland has gained 500 Gt of ice this winter (2016-2017)

Here you can follow the daily surface mass balance on the Greenland Ice Sheet. The snow and ice model from one of DMI’s climate models is driven every six hours with snowfall, sunlight and other parameters from a research weather model for Greenland, Hirlam-Newsnow.

The interaction of climate change and methane hydrates

by C.D. Ruppel and J.D. Kessler, 8 February 2017


Gas hydrate, a frozen, naturally-occurring, and highly-concentrated form of methane, sequesters significant carbon in the global system and is stable only over a range of low-temperature and moderate-pressure conditions. Gas hydrate is widespread in the sediments of marine continental margins and permafrost areas, locations where ocean and atmospheric warming may perturb the hydrate stability field and lead to release of the sequestered methane into the overlying sediments and soils. Methane and methane-derived carbon that escape from sediments and soils and reach the atmosphere could exacerbate greenhouse warming.

Absence of 21st century warming on Antarctic Peninsula consistent with natural variability

John Turner et al., Nature, July 2016


Here we use a stacked temperature record to show an absence of regional warming since the late 1990s. The annual mean temperature has decreased at a statistically significant rate, with the most rapid cooling during the Austral summer. Temperatures have decreased as a consequence of a greater frequency of cold, east-to-southeasterly winds, resulting from more cyclonic conditions in the northern Weddell Sea associated with a strengthening mid-latitude jet.

La géologie, une science plus que passionnante … et diverse