Archives par mot-clé : Methane

‘MASSIVE POOL’ OF METHANE HIDDEN DEEP BENEATH EARTH’S SURFACE DISCOVERED BY SCIENTISTS

by Hannay Osborne, 21 August 2019 in Newsweek from PNAS


A huge source of methane has been discovered deep beneath the surface of Earth, sitting between the upper mantle and lower oceanic crust. The discovery is important as it could provide an insight into the hydrothermal vents that may have helped the planet’s first life emerge. Researchers also argue it could be a source of hydrogen and methane on other planets in the solar system—”even those where liquid water is no longer present.”

The ‘abiotic’ methane—methane that is not formed with organic matter—was found locked inside rocks. Researchers from the Woods Hole Oceanographic Institution (WHOI), Massachusetts, took 160 samples from hydrothermal sites across the globe, including the Mid-Atlantic Ridge, Guaymas Basin, the East Pacific Rise and the Mid-Cayman Rise. After analyzing them with a laser-based microscope, they found that almost all contained pockets of methane.

In their study, published in the journal PNAS, the team says this could be the biggest source of abiotic methane in the world. This reservoir, they say, could account for more methane than was in Earth’s atmosphere before the onset of the industrial era.

The methane appears to have formed by reactions between trapped water and olivine, a group of rock-forming minerals found in the planet’s subsurface. When seawater moves through the deep ocean crust, it mixes with magma-hot olivine. When the mineral cools, the water is trapped inside and a chemical reaction takes place, leading to the formation of hydrogen and methane.

Traditionally, we think of methane—a potent greenhouse gas—as forming when organic material breaks down. When it is emitted into the atmosphere, it has a warming effect far greater than carbon dioxide, although it is far shorter-lived than the latter, disappearing after about a decade.

However, methane is also known to exist on the seafloor. It is released through deep-sea vents—geothermally heated fissures on Earth’s crust. In 2016, scientists with the Ocean Exploration Trust discovered over 500 methane spewing vents off the west coast of the U.S.

However, the source of the seafloor methane has remained something of a mystery. “Identifying an abiotic source of deep-sea methane has been a problem that we’ve been wrestling with for many years,” study author Jeffrey Seewald, a senior scientist at WHOI, said in a statement.

Lead author Frieder Klein added: “We were totally surprised to find this massive pool of abiotic methane in the oceanic crust and mantle. Here’s a source of chemical energy that’s being created by geology.”

Net Zero Natural Gas Plant — The Game Changer

by James Conca, July 31, 2019 in Forbes


An actual game changing technology is being demonstrated as we sit in our air-conditioned abodes reading this. And it is being demonstrated by North Carolina–based Net Power at a new plant in La Porte, Texas.

The process involves burning fossil fuel with oxygen instead of air to generate electricity without emitting any carbon dioxide (CO2). Not using air also avoids generating NOx, the main atmospheric and health contaminant emitted from gas plants.

Study: Cattle Methane is a moooot point in global climate

by Anthony Watts, June 12, 2019 in WUWT


Via No Tricks Zone: Agrobiologist and scientific researcher Dr. Albrecht Glatzle, author of over 100 scientific papers and two textbooks, has published research that shows:

“…there is no scientific evidence, whatsoever, that domestic livestock could represent a risk for the Earth’s climate” and the “warming potential of anthropogenic GHG [greenhouse gas] emissions has been exaggerated.”

Glatzle, 2018

Domestic Livestock and ItsAlleged Role in Climate Change

Abstract:

“Our key conclusion is there is no need for anthropogenic emissions of greenhouse gases (GHGs), and even less so for livestock-born emissions, to explain climate change. Climate has always been changing, and even the present warming is most likely driven by natural factors.

The warming potential of anthropogenic GHG emissions has been exaggerated, and the beneficial impacts of manmade CO2 emissions for nature, agriculture, and global food security have been systematically suppressed, ignored, or at least downplayed by the IPCC (Intergovernmental Panel on Climate Change) and other UN (United Nations) agencies.

Furthermore, we expose important methodological deficiencies in IPCC and FAO (Food Agriculture Organization) instructions and applications for the quantification of the manmade part of non-CO2-GHG emissions from agro-ecosystems.

However, so far, these fatal errors inexorably propagated through the scientific literature.

Finally, we could not find a clear domestic livestock fingerprint, neither in the geographical methane distribution nor in the historical evolution of mean atmospheric methane concentration.”

Methane-consuming bacteria could be the future of fuel

by Northwestern University, May 9, 2019 in ScienceDaily


Discovery illuminates how bacteria turn methane gas into liquid methanol.
Researchers have found that the enzyme responsible for the methane-methanol conversion in methanotrophic bacteria catalyzes the reaction at a site that contains just one copper ion. This finding could lead to newly designed, human-made catalysts that can convert methane — a highly potent greenhouse gas — to readily usable methanol with the same effortless mechanism.
The study will publish on Friday, May 10 in the journal Science. Rosenzweig is the Weinberg Family Distinguished Professor of Life Sciences in Northwestern’s Weinberg College of Arts and Sciences. Hoffman is the Charles E. and Emma H. Morrison Professor of Chemistry at Weinberg.

By oxidizing methane and converting it to methanol, methanotrophic bacteria (or “methanotrophs”) can pack a one-two punch. Not only are they removing a harmful greenhouse gas from the environment, they are also generating a readily usable, sustainable fuel for automobiles, electricity and more.

Current industrial processes to catalyze a methane-to-methanol reaction require tremendous pressure and extreme temperatures, reaching higher than 1,300 degrees Celsius. Methanotrophs, however, perform the reaction at room temperature and “for free”.

Methane warming exaggerated by 400%

by Barry Brill, March 30, 2019 in WUWT


The IPCC’s AR5 estimated the global warming caused by a tonne of livestock methane would be 28 times that of a tonne of carbon dioxide. New research destroys that estimate.

The war on meat has been gathering pace amongst our Western elites. The Economist makes a detailed case for “plant-based food” in the interests of quelling climate change –

The FAO calculates that cattle generate up to two-thirds of the greenhouse gases from livestock, and are the world’s fifth largest source of methane. If cows were a country, the United Herds of Earth would be the planet’s third largest greenhouse-gas emitter.

These calculations are based on figures supplied by the IPCC’s AR5, which contends that the global warming potential (GWP) of methane over 100 years is no less than 28 times the global warming it expects to be caused by an equivalent weight of carbon dioxide. This estimate is up from the GWP of 21 put forward in the IPCC’s previous report.

All this is now challenged by a new and authoritative research paper, Allen et al (2017): “A solution to the misrepresentations of CO2-equivalent emissions of short-lived climate pollutants, under ambitious mitigation”. This paper finds that conventional GWPs misrepresent the impact of short-lived gases (such as methane) on global temperature – and recommends the adoption of a new metric, denoted as GWP*.

China’s Greenhouse Gas Emissions Rising At ‘Alarming Rate’

by Anthony Watts, February 5, 2019 in WUWT


The paper: https://www.nature.com/articles/s41467-018-07891-7

China’s coal mine methane regulations have not curbed growing emissions

Abstract

Anthropogenic methane emissions from China are likely greater than in any other country in the world. The largest fraction of China’s anthropogenic emissions is attributable to coal mining, but these emissions may be changing; China enacted a suite of regulations for coal mine methane (CMM) drainage and utilization that came into full effect in 2010. Here, we use methane observations from the GOSAT satellite to evaluate recent trends in total anthropogenic and natural emissions from Asia with a particular focus on China. We find that emissions from China rose by 1.1 ± 0.4 Tg CH4 yr−1 from 2010 to 2015, culminating in total anthropogenic and natural emissions of 61.5 ± 2.7 Tg CH4 in 2015. The observed trend is consistent with pre-2010 trends and is largely attributable to coal mining. These results indicate that China’s CMM regulations have had no discernible impact on the continued increase in Chinese methane emissions.

New Research: Methane Emissions From Livestock Have No Detectable Effect On The Climate

by Kenneth Richard, December 3, 2018 in NoTricksZone


Agrobiologist and scientific researcher Dr. Albrecht Glatzle, author of over 100 scientific papers and two textbooks, has published research that shows “there is no scientific evidence, whatsoever, that domestic livestock could represent a risk for the Earth’s climate” and that the “warming potential of anthropogenic GHG [greenhouse gas] emissions has been exaggerated”.

Minimal geological methane emissions during the Younger Dryas–Preboreal abrupt warming event

by Vasilii V. Petrenko et al., August 23, 2017 in Nature


Preboreal event was driven by contemporaneous methane from sources such as wetlands; our findings constrain the contribution from old carbon reservoirs (marine methane hydrates8, permafrost9 and methane trapped under ice10) to 19 per cent or less (95 per cent confidence). To the extent that the characteristics of the most recent deglaciation and the Younger Dryas–Preboreal warming are comparable to those of the current anthropogenic warming, our measurements suggest that large future atmospheric releases of methane from old carbon sources are unlikely to occur.

Après le pétrole, le gaz américain comme nouveau “game changer” ?

by Patrice Geoffron, 23 octobre 2017 in Le CerclesdesEconmistes, Boursorama


 (…) le gaz américain pourrait bouleverser les équilibres mondiaux, avec des conséquences non moins drastiques que pour le pétrole. Les ressources américaines de gaz sont abondantes et, en juillet 2017, le prix interne a atteint son point le plus bas depuis 12 ans, augurant de sa compétitivité à l’export.

…Next Generation of Fossil Fuels…

by Donn Dears, August 2017


As noted in my article four years ago, Japan has a program for producing natural gas from methane hydrates located near its coast, and predicts it will be successful by 2019.

Most people believe that Japan’s objective is highly optimistic, but it does shed light on the efforts currently underway to develop the technology for extracting natural gas from methane hydrates.

Réserves de gaz dans le monde

by Connaissances des Energies, 17 février 2015


Les cinq pays disposant des plus importantes réserves de gaz au monde sont :

Methane Emissions: from blind spot to spotlight

by The Oxford Institute for Energy Studies, July 2017


Very comprehensive file, 39 pages .pdf

Methane emissions influence but do not undermine the environmental case for gas. If the industry can build on the progress to date and deliver a clearer picture on the level of emissions and actions to address them, the arguments for gas displacing coal in power generation and oil products in transport become much stronger.

The Vostok Ice Core: Temperature, CO2 and CH4

by Euan Means, December 12, 2014


In their seminal paper on the Vostok Ice Core, Petit et al (1999) [1] note that CO2 lags temperature during the onset of glaciations by several thousand years but offer no explanation. They also observe that CH4 and CO2 are not perfectly aligned with each other but offer no explanation. The significance of these observations are therefore ignored. At the onset of glaciations temperature drops to glacial values before CO2 begins to fall suggesting that CO2 has little influence on temperature modulation at these times.

See also here

CHINA CLAIMS METHANE HYDRATES BREAKTHROUGH MAY LEAD TO GLOBAL ENERGY REVOLUTION

by CNN Money, May 21, 2017 in GWPF


The fuel-hungry country has been pursuing the energy source, located at the bottom of oceans and in polar regions, for nearly two decades. China’s minister of land and resources, Jiang Daming, said Thursday that the successful collection of the frozen fuel was “a major breakthrough that may lead to a global energy revolution,” according to state media.

Experts agree that flammable ice could be a game changer for the energy industry, similar to the U.S. shale boom. But they caution that big barriers — both technological and environmental — need to be cleared to build an industry around the frozen fuel, which is also known as gas hydrate.

Are methane seeps in the Arctic slowing global warming?

by Randall Hayman, May 8, 2017, in Science


Good news about climate change is especially rare in the Arctic. But now comes news that increases in one greenhouse gas—methane—lead to the dramatic decline of another. Research off the coast of Norway’s Svalbard archipelago suggests that where methane gas bubbles up from seafloor seeps, surface waters directly above absorb twice as much carbon dioxide (CO2) as surrounding waters. The findings suggest that methane seeps in isolated spots in the Arctic could lessen the impact of climate change.

Methane-munching microbes living in the deep biosphere for 400 million years: An analogue for extra-terrestrial life

by Linnaeus University, May 9, 2017 in ScienceDaily


It is becoming more and more appreciated that a major part of the biologic activity is not going on at the ground surface, but is hidden underneath the soil down to depths of several kilometres in an environment coined the “deep biosphere”. Studies of life-forms in this energy-poor system have implications for the origin of life on our planet and for how life may have evolved on other planets, where hostile conditions may have inhibited colonization of the surface environment. The knowledge about ancient life in this environment deep under our feet is extremely scarce.

Methane seeps in the Canadian high Arctic

by Geological Society of America, April 13, 2017

in ScienceDaily


Cretaceous climate warming led to a significant methane release from the seafloor, indicating potential for similar destabilization of gas hydrates under modern global warming. A field campaign on the remote Ellef Ringnes Island, Canadian High Arctic, discovered an astounding number of methane seep mounds in Cretaceous age sediments.

Methane emissions from trees

Tree trunks act as methane source in upland forests

by University of Delaware, March 30, 2017


Methane is about 25 times stronger than carbon dioxide, with some estimates as high as 33 times stronger due to its effects when it is in the atmosphere.

Because of methane’s global warming potential, identifying the sources and “sinks” or storehouses of this greenhouse gas is critical for measuring and understanding its implications across ecosystems.

Daniel L. Warner, Samuel Villarreal, Kelsey McWilliams, Shreeram Inamdar, Rodrigo Vargas. Carbon Dioxide and Methane Fluxes From Tree Stems, Coarse Woody Debris, and Soils in an Upland Temperate ForestEcosystems, 2017; DOI: 10.1007/s10021-016-0106-8

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.

La contribution du gaz naturel dans le mix énergétique augmente dans tous les scénarios

M.J. Nadeau, Conseil mondial de l’énergie, 2016-2017

Réunis au congrès triennal du Conseil mondial de l’énergie (CME) à Istanbul en octobre 2016, les leaders du secteur de l’énergie ont tous témoigné de l’importance des bouleversements auxquels l’industrie est confrontée. Pour nous aider à comprendre les phénomènes qui prévalent et leurs  impacts sur le secteur, le CME a publié fin 2016 son dernier rapport sur les scénarios énergétiques mondiaux(1). Ce rapport explore trois scénarios possibles à l’horizon 2060 et fournit aux experts un cadre de réflexion utile.

Le gaz abiotique naturel

par Alain Préat


Probablement pas une nouvelle source rentable d’hydrocarbures…

Tous les hydrocarbures naturels, c’est- à-dire le pétrole y compris le gaz méthane (CH4) parmi d’autres gaz, sont essentiellement liés à l’évolution de la matière organique au cours de son enfouissement dans les séries géologiques. Une partie du méthane sur Terre peut également être produite par des microorganismes adaptés à la vie dans les milieux extrêmes, souvent en l’absence d’oxygène [1]. Mais il est moins connu que le méthane peut aussi être produit par l’altération et/ou le métamorphisme de roches magmatiques basiques et ultraba- siques donnant des serpentinites à partir des péridotites du manteau supérieur [2]. Ces roches présentes à la fois dans les zones océaniques (les dorsales médio-océaniques) et sur les continents dans les zones dites cratoniques (anciennes croûtes continentales très épaisses) sont à l’origine de la production de méthane non biogénique. Les serpentinites résultent de réactions d’hydratation à basse température (< 100°C) des roches ultrabasiques et, outre la production de méthane surtout en présence de dioxyde de carbone, elles sont aussi à l’origine de la production de faibles quantités d’hydrogène (seul mode de production abiotique sur la Terre), d’azote et d’hélium. Cet hydrocarbure abiotique (le méthane) mantellique pourrait être lié à l’origine de la vie sur Terre et le processus expliquerait aussi la présence de différents hydrocarbures sur d’autres planètes et dans de rares météorites. Sur notre planète, on le trouve lié aux systèmes hydrothermaux, aux édifices volcaniques, aux intrusions ignées (roches magmatiques mises en place dans des formations déjà constituées), dans les boucliers cristallins (roches magmatiques et métamorphiques du Précambrien), au Japon, en Nouvelle-Zélande, en Grèce, en Italie, en Russie, aux USA, en Chine, à Oman etc.

Une des plus belles occurrences est celle du site Chimaera dans le Golfe d’Antalya en Turquie, le plus grand champ onshore [3] de méthane abiotique actuel. En effet, ce champ est lié à une zone faillée avec serpentinisation de péridotites et d’ophiolites suite à l’obduction [4] des Alpes. Le gaz de Chimaera (87% de méthane, 10% d’hydrogène et quelques pourcents d’autres hydrocarbures) brûle en formant une vingtaine de flammes de 50 cm de hauteur. Ce méthane s’échappe également sans brûler à partir de failles ou de fissures qui libèrent annuellement environ 200 tonnes de ce gaz dans l’atmosphère. Les arbres et les sols de la région sont totalement brûlés sur 2000 m2. Les analyses isotopiques du carbone et de l’hydrogène confirment qu’il s’agit bien de gaz abiotique. Des datations au carbone 14 montrent que cette source gazeuse a plus de 50 000 ans d’âge. Elles furent observées par Pline l’Ancien il y a près de 2000 ans qui les considérait comme des « flammes éternelles ». Le méthane émis jusqu’à aujourd’hui est de l’ordre de 400 millions de mètres cubes et représente une faible portion d’un réservoir sous pression. Homère (fin du VIIIe siècle avant J-C) avait déjà noté dans l’Iliade la présence de Chimères ou monstres crachant du feu et dévorant les humains à Chimaera près du site archéologique de Cirali.

Qu’en est-il de l’aspect commercial de ce gaz ? On estime aujourd’hui que ce méthane abiotique représente bien moins de 1 % du gaz présent dans la plupart des réservoirs d’hydrocarbures. Son évaluation reste à faire, d’autant plus qu’il ne peut être mis en évidence que par des analyses isotopiques détaillées du carbone, de l’hydrogène et/ou de l’hélium (ce dernier provenant du manteau). De plus, jusqu’à aujourd’hui, ce gaz n’a été mis en évidence que sur la partie continentale du Globe (onshore), rien ou très peu est connu au niveau de la partie offshore immergée, par exemple au niveau des dorsales médio-océaniques où l’altération des péridotites est un processus dominant.

Sept sites hydrothermaux actifs producteurs de méthane, d’hydrogène et d’azote abiotiques suite aux processus de serpentinisation sont connus le long de la dorsale médio-atlantique et chaque site fonctionnerait plusieurs dizaines de milliers d’années (au moins 30 000 ans) avant de s’éteindre. La théorie du gaz (et du pétrole) abiotique formé à grande profondeur (à partir de dépôts de carbone, datant peut-être de la formation de la Terre) a été développée en Union Soviétique (et Ukraine) après la Seconde Guerre mondiale et a jeté le trouble dans la communauté scientifique pendant fort longtemps. À ce moment-là, les grands champs pétroliers du Moyen- Orient venaient d’être découverts et la formation du pétrole était encore sujette à discussion. Les mécanismes proposés par les soviétiques se sont révélés erronés et la théorie a été abandonnée après quelques décennies (1950-1980) lorsque l’origine organique du pétrole (cf. SPS, n°312 [5]) a été définitivement démontrée. Néanmoins la « théorie soviétique » continue à intriguer les non spécialistes et constitue d’ailleurs l’objet de l’intrigue majeure d’une BD récemment parue aux éditions du Lombard [6].

Notons enfin que depuis 1913, la chimie est à même de produire du méthane en laboratoire à partir de dioxyde de carbone et d’hydrogène ce qui a valu à Paul Sabatier le prix Nobel. Depuis lors, la « réaction Sabatier » fut menée suivant plusieurs voies, par exemple en remplaçant le dioxyde de carbone par le monoxyde de carbone (réaction Fischer-Tropsch ayant permis à l’Allemagne nazie et à l’Afrique du Sud – au temps de l’apartheid – de produire du méthane à partir de charbon). Les réactions chimiques ont cependant lieu à des températures nettement plus élevées que celle de production du gaz non biogénique naturel.

En conclusion, en l’état actuel des connaissances, le méthane abio- tique bien que non quantifié n’a pas le potentiel d’une source d’hydrocarbures rentable. En effet, il semble- rait qu’il soit associé en très faible quantité aux hydrocarbures habituels (pétrole et gaz biotiques) et est donc exploité avec ces derniers.

Alain Préat

Géologue, professeur à l’ULB (Université Libre de Bruxelles), département des Sciences de la Terre et de l’Environnement.

1 Il s’agit des Archées (encore appelées Archéobactéries) c’est-à-dire de microorganismes unicellulaires proca- ryotes (pas de noyau, pas d’organites) adaptés à la vie dans les milieux extrêmes, souvent en l’absence d’oxygène (sources hydrothermales du fond des océans, lacs salés, marais, sols… y compris dans le corps humain – par exemple le colon).

2 Enveloppe du Globe limitée par la base de la croûte aux environs de 10 à 30 km de profondeur et le manteau infé- rieur à environ 700 km de profondeur. Elle est composée de péridotites, roches riches en magnésium et assez pauvres en aluminium. Les roches basiques et ultrabasiques sont des roches magma- tiques très pauvres en silice, elles contiennent plus de 90% de minéraux riches en fer et magnésium (olivine, pyroxène…). Le métamorphisme est la transformation d’une roche à l’état solide suite à une élévation de la température et/ou de la pression.

3 À terre, sur le continent, par opposition à offshore, en mer.

4 Chevauchement d’une vaste portion de croûte océanique (représentée par des complexes ophiolitiques) sur une zone de croûte continentale. Les ophiolites représentent ici des péridotites foliées ayant subi des déformations tec-toniques.

5 Gisements supergéants disparus : le pétrole du Précambrien. www.pseudo- sciences.org/spip.php?article2419

6 Quand la fiction s’inspire de la réalité : du pétrole plein les cases www.ulb.ac.be/sciences/dste/sediment/pa ges_perso/Preat_fichiers/BD_Petrole.pdf