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Pedro J. Hdez
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Nunca atribuyo a una conspiración aquello que pueda explicarse por simple incompetencia
Nunca atribuyo a una conspiración aquello que pueda explicarse por simple incompetencia

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En defensa del argumento de autoridad y el consenso científico. Mi blog personal, habitualmente en hibernación, vuelve hoy a la vida.
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Electricity and energy in the G20

G20 countries obtain only 41.5% of their total energy from electricity and the remaining 58.5% dominantly from oil, coal and gas consumed in the non-electric sector (transportation, industrial processes, heating etc). So even if they eventually succeed in obtaining all their electricity from low-carbon sources they would still be getting more than half their energy from high-carbon sources if no progress is made in decarbonizing their non-electric sectors.
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"The mining and milling of Canadian uranium contributes very few greenhouse gases to nuclear power’s already low emissions, a research group has found".
"The mining and milling of Canadian uranium contributes very few greenhouse gases to nuclear power’s already low emissions, a research group has found".

(Posted by +rasha kamel​)
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"This long-term view shows that the next few decades offer a brief window of opportunity to minimize large-scale and potentially catastrophic climate change that will extend longer than the entire history of human civilization thus far."

"Humans have been burning fossil fuels for only about 150 years, yet that has started a cascade of profound changes that at their current pace will still be felt 10,000 years from now."
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A strange thing happened in the stratosphere

"This disruption to the wind pattern - called the "quasi-biennial oscillation" - did not have any immediate impact on weather or climate as we experience it on Earth's surface. But it does raise interesting questions for the NASA scientists who observed it: If a pattern holds for six decades and then suddenly changes, what caused that to happen? Will it happen again? What effects might it have?
"The quasi-biennial oscillation is the stratosphere's Old Faithful," said Paul Newman, Chief Scientist for Earth Sciences at NASA's Goddard Space Flight Center, Greenbelt, Maryland, and lead author on a new paper about the event published online in Geophysical Research Letters. "If Old Faithful stopped for a day, you'd begin to wonder about what was happening under the ground."
Winds in the tropical stratosphere, an atmospheric layer that extends from about 10 to 30 miles above Earth's surface, circulate the planet in alternating easterly and westerly directions over roughly a two-year period. Westerly winds develop at the top of the stratosphere, and gradually descend to the bottom, about 10 miles above the surface while at the same time being replaced by a layer of easterly winds above them. In turn, the easterlies descend and are replaced by westerlies.
This pattern repeats every 28 months. In the 1960s scientists coined it the "quasi-biennial oscillation." The record of these measurements, made by weather balloons released in the tropics at various points around the globe, dates to 1953.
The pattern never changed - until late 2015. As the year came to a close, winds from the west neared the end of their typical descent. The regular pattern held that weaker easterly winds would soon replace them. But then the westerlies appeared to move upwards and block the downward movement of the easterlies. This new pattern held for nearly half a year, and by July 2016 the old regime seemed to resume.
"It's really interesting when nature throws us a curveball," Newman said.
The quasi-biennial oscillation has a wide influence on stratospheric conditions. The amount of ozone at the equator changes by 10 percent between the peaks of the easterly and westerly phases, while the oscillation also has an impact on levels of polar ozone depletion".
"This disruption to the wind pattern - called the "quasi-biennial oscillation" - did not have any immediate impact on weather or climate as we experience it on Earth's surface. But it does raise interesting questions for the NASA scientists who observed it: If a pattern holds for six decades and then suddenly changes, what caused that to happen? Will it happen again? What effects might it have?
"The quasi-biennial oscillation is the stratosphere's Old Faithful," said Paul Newman, Chief Scientist for Earth Sciences at NASA's Goddard Space Flight Center, Greenbelt, Maryland, and lead author on a new paper about the event published online in Geophysical Research Letters. "If Old Faithful stopped for a day, you'd begin to wonder about what was happening under the ground."
Winds in the tropical stratosphere, an atmospheric layer that extends from about 10 to 30 miles above Earth's surface, circulate the planet in alternating easterly and westerly directions over roughly a two-year period. Westerly winds develop at the top of the stratosphere, and gradually descend to the bottom, about 10 miles above the surface while at the same time being replaced by a layer of easterly winds above them. In turn, the easterlies descend and are replaced by westerlies.
This pattern repeats every 28 months. In the 1960s scientists coined it the "quasi-biennial oscillation." The record of these measurements, made by weather balloons released in the tropics at various points around the globe, dates to 1953.
The pattern never changed - until late 2015. As the year came to a close, winds from the west neared the end of their typical descent. The regular pattern held that weaker easterly winds would soon replace them. But then the westerlies appeared to move upwards and block the downward movement of the easterlies. This new pattern held for nearly half a year, and by July 2016 the old regime seemed to resume.
"It's really interesting when nature throws us a curveball," Newman said.
The quasi-biennial oscillation has a wide influence on stratospheric conditions. The amount of ozone at the equator changes by 10 percent between the peaks of the easterly and westerly phases, while the oscillation also has an impact on levels of polar ozone depletion".

(Posted by +rasha kamel​)
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Climate change in a shoebox: Right result, wrong physic

Classroom experiments that purport to demonstrate the role of carbon dioxide’s far-infrared absorption in global climate change are more subtle than is commonly appreciated. We show, using both experimental results and theoretical analysis, that one such experiment demonstrates an entirely different phenomenon: The greater density of carbon dioxide compared to air reduces heat transfer by suppressing convective mixing with the ambient air. Other related experiments are subject to similar concerns. Argon, which has a density close to that of carbon dioxide but no infrared absorption, provides a valuable experimental control for separating radiative from convective effects. A simple analytical model for estimating the magnitude of the radiative greenhouse effect is presented, and the effect is shown to be very small for most tabletop experiments.
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There is  no evidence that renewables are having a detectable impact on Germany’s emissions, which have not decreased since 2009 despite a doubling of renewables penetration in the electricity sector. It now seems certain that Germany will miss its 2020 emissions reduction target, quite possibly by a wide margin. In short, the Energiewende is starting to unravel.
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Climas posibles de Próxima b. Nueva entrada en el blog de climatología donde se estudian algunas características de los posibles climas del exoplaneta recién descubierto en base a modelos sencillos de equilibrio radiativo. El objetivo es mostrar otro ejemplo más de la potencia de los modelos sencillos para ciertos argumentos de tipo general.
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Positioning exact to the millimeter: Geodetic reference system enables highly accurate positioning https://www.sciencedaily.com/releases/2016/08/160825100943.htm
"How many millimeters has the sea level risen? How fast are the continents moving? In order to answer these questions, measurements are being made around the clock at more than 1,700 globally distributed observing stations. These data are then evaluated by researchers. Their new realization of the global reference system that has now been published, is so exact that it even allows to detect seasonal variations".

(Posted by +rasha kamel​)
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Entrada bastante técnica en el blog donde construyo un modelo de equilibrio radiativo multicapa continuo que permite calcular un perfil de temperaturas (poco realista) para la atmósfera, tanto numéricamente (implementado en python en una hoja de SAGE) como analíticamente. El modelo permite de manera sencilla entender varios conceptos fundamentales del transporte radiativo en las atmósferas planetarias que se suelen presentar de manera mucho más abstracta, tal y como  la ley de Beer-Lambert, la profundidad óptica y las ecuaciones de Schwarzchild en la aproximación de dos flujos para una atmósfera plano-pararela, que además permite obtener una solución analítica para el perfil de temperaturas.
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