Archives quotidiennes :

only geology

Meteorite study suggests Earth may have been wet since it formed

by Washington University in St. Louis, Aug 27, 2020 in ScienceDaily

Enstatite chondrite meteorites, once considered ‘dry,’ contain enough water to fill the oceans — and then some

A new study finds that Earth’s water may have come from materials that were present in the inner solar system at the time the planet formed — instead of far-reaching comets or asteroids delivering such water. The findings published Aug. 28 in Science suggest that Earth may have always been wet.

Researchers from the Centre de Recherches Petrographiques et Geochimiques (CRPG, CNRS/Universite de Lorraine) in Nancy, France, including one who is now a postdoctoral fellow at Washington University in St. Louis, determined that a type of meteorite called an enstatite chondrite contains sufficient hydrogen to deliver at least three times the amount of water contained in the Earth’s oceans, and probably much more.

Enstatite chondrites are entirely composed of material from the inner solar system — essentially the same stuff that made up the Earth originally.

“Our discovery shows that the Earth’s building blocks might have significantly contributed to the Earth’s water,” said lead author Laurette Piani, a researcher at CPRG. “Hydrogen-bearing material was present in the inner solar system at the time of the rocky planet formation, even though the temperatures were too high for water to condense.”

…

climate-debate

GRAND SOLAR MINIMUM INCOMING

by Cap Allon, August 27, 2020 in Electroverse

Solar Cycle 25 may be spluttering into life, but all is once-again quiet on the earth-facing solar disc: there are no sunspots — in fact, there haven’t been any for the past 6 days (as of Aug 27, 2020).

Solar activity is the driving force of Earth’s climate. This definition of obvious is only disputed by the misinformed, and by those with a financial or political motive.

High solar activity — as we’ve enjoyed for the past 100-or-so years — has delivered our planet a stable, predictable climate under-which we modern humans have had the opportunity to thrive and successfully advance our technological society.

However, and as with all good things, these predictable days are ending: the Sun’s output is waning to levels not seen for the past 200 years, to a reduction in activity not experienced since the Dalton Minimum(1790-1830). And as with every great and advancing civilization of the past, a time comes when the consequences of a solar shutdown need to be contended. We need to prepare for the wild swings-between-extremes brought about by an increasingly weak & wavy (meridional) jet stream, we need to be aware of a powerful volcanic uptick witnessed during times of low solar activity, as well as cloud-nucleating Cosmic Rays, and, perhaps most crucially, an overall cooling of the planet.

Crops are always the first to go. And our modern delicately-balanced, chemical-dependent, monocropping-ways simply aren’t prepared for a violent shift in the climate — as Robert Felix has long been warning, “I fear that we will be fighting in the streets for food long before we’re covered by ice.”

 

…

better to know...?, climate-debate

When will Temperatures start to fall? Part1

by Tony Brown, August 28, 2020 in WUWT

“If Europeans truly mobilize around the delivery of the 2050 goal, every business decision, lifestyle choice, political swing, every hallmark of European culture — from annual ski trips, to Champions League Football matches, to French cheese — will need to be tested against its contribution to climate change.” European Commission ‘Green Deal’ March 2020

This is an article with a simple proposition.  Science tells us that rapidly rising Co2 in turn causes rising temperatures, which has become a very serious problem for humanity.

The three questions I ask, in the expectation that the answer can be provided from main stream published science is;

“Assuming we reach zero carbon emissions by 2030-Extinction Rebellion (XR) requirement,  or 2050 -the aim of most governments under the Paris Accord- 1) how long would it take for Co2 levels to naturally fall below the’ safe upper limits’ of 350ppm espoused by such as James Hansen; 2) for it to fall further to 280ppm -the previous pre industrial level -AND 3) when will temperatures start to fall in turn, to achieve pre industrial levels, said to be 1 to 2 degrees Centigrade below present, according to the IPCC.”

There are all sorts of caveats of course, with methane, water vapour, clouds, feedbacks, ocean response, natural variations etc but having scoured various ‘official’ web sites I can find no definitive estimate. An examination of the Extinction Rebellion web site demonstrates they are anarchists, rather than a serious green organisation. A couple of more reasoned attempts to track the consequences of zero carbon emissions are given in Note 3below the graphic-Figure 1 together with a variety of other useful background information.

Whether the reader personally believes excess Co2 to be a problem is not a matter this article is concerned with.  Let’s take science at face value –our respective Governments  have overwhelmingly agreed that humanity has added some 140ppm of Co2 to the pre industrial 280ppm and that, as a result, temperatures have risen substantially and are at a dangerous level and causing extremes of weather.

…

climate-debate

Le 20ème siècle a été anormalement chaud mais le 21èmesiècle revient à la normale (2/2)

by Jean Van Vliet, 22 août 2020 in ScienceClimatEnergie

Cet article fait suite à la première partie (1/2) publiée par SCE le 14 août 2020.

5. La longueur des cycles solaires

Le passage d’un cycle solaire au cycle suivant est défini en principe par le changement de signe du champ magnétique autour des taches solaires. Le moment de ce passage est difficile à déterminer dans le cas des cycles longs, parce qu’on peut avoir pendant plusieurs années cohabitation, dans le même hémisphère solaire, de taches solaires d’orientations magnétiques différentes. Ainsi, à l’heure d’écriture de cet article (juillet 2020), la fin du cycle solaire 24 se rapproche, mais les premières taches avec l’orientation magnétique du cycle 25 ont fait leur apparition dès 2019; si  le cycle 24 n’était pas terminé avant la fin de cette année, la transition du cycle 24 au cycle 25 serait étalée sur 3 années.

De manière à tirer profit de la richesse des données disponibles sur le site (ici)  la longueur des cycles solaires est déterminée comme suit: pour les cycles allant de 1700 à 1755, seules les moyennes annuelles du nombre de taches solaires sont disponibles et le début de cycle correspond à l’année suivant le minimum de cette moyenne. Pour les cycles allant de 1755 à nos jours, la longueur est déterminée en utilisant les moyennes mensuelles: le début de cycle correspond au mois à partir duquel s’amorce la montée du nombre de taches. Cette méthode diffère de celle utilisée par Friis-Christensen et Lassen [29] et Butler et Johnston [30] qui ont travaillé par interpolation au départ des valeurs mensuelles lissées sur 13 mois.

Comme nous allons le voir, la longueur des cycles solaires varie de 9 ans minimum (cycles 2, 3 et 8) à 14 ans (cycle 4 marquant le début du Minimum de Dalton et la Révolution française). La Figure 5 fournit les longueurs des 29 cycles solaires observés depuis le début du 18ème siècle, chaque valeur étant positionnée au milieu du cycle correspondant.  La figure suggère que la dispersion des cycles solaires va diminuant du 18ème au 20èmesiècle: de manière à préciser cette impression, on calcule dans le tableau suivant, pour chacun des siècles considérés, les longueurs moyennes des cycles solaires (en années) et leurs déviations standard.

Figure 5 : Longueur des 29 cycles solaires observés du 18ème au 21ème siècle.

Le résultat le plus frappant de ce tableau est que les cycles solaires du  20ème siècle sont en moyenne un an plus courts que ceux du 19ème siècle, la tendance s’inversant avec les 2 premiers cycles du 21ème siècle. En appliquant la corrélation de Butler et Johnston [24], ceci rendrait le 20ème siècle plus chaud de 0,5°C en moyenne que le 19ème siècle.

…