General > The Big Picture
El Hilo del Clima y el Cambio Climático
Currobena:
Como me parece un tema interesante y no he visto ningún hilo específico sobre el clima y el cambio climático, abro éste y pongo un artículo donde se analiza la posibilidad de que el cambio climático sea a enfriamiento en lugar de a calentamiento global:
--- Citar ---Top Scientists, Government Agencies and Publications Have – For Over 100 Years – Been Terrified of a New Ice Age
Posted on April 15, 2012 by WashingtonsBlog
Fear of the Big Freeze
There has been an intense debate among leading scientists, government agencies and publications over whether the bigger threat is global warming or a new ice age. As we’ve previously noted, top researchers have feared an ice age – off and on – for more than 100 years. (This post does not weigh in one way or the other. It merely presents a historical record.)
On February 24, 1895, the New York Times published an article entitled “PROSPECTS OF ANOTHER GLACIAL PERIOD; Geologists Think the World May Be Frozen Up Again”, which starts with the following paragraph:
The question is again being discussed whether recent and long-continued observations do not point to the advent of a second glacial period, when the countries now basking in the fostering warmth of a tropical sun will ultimately give way to the perennial frost and snow of the polar regions.
In September 1958, Harper’s wrote an article called “The Coming Ice Age”.
On January 11, 1970, the Washington Post wrote an article entitled “Colder Winters Held Dawn of New Ice Age – Scientists See Ice Age In the Future” which stated:
Get a good grip on your long johns, cold weather haters–the worst may be yet to come. That’s the long-long-range weather forecast being given out by “climatologists.” the people who study very long-term world weather trends.
In 1972, two scientists – George J. Kukla (of the Lamont-Doherty Geological Observatory) and R. K. Matthews (Chairman, Dept of Geological Sciences, Brown University) – wrote the following letter to President Nixon warning of the possibility of a new ice age:
Dear Mr. President:
Aware of your deep concern with the future of the world, we feel obliged to inform you on the results of the scientific conference held here recently. The conference dealt with the past and future changes of climate and was attended by 42 top American and European investigators. We enclose the summary report published in Science and further publications are forthcoming in Quaternary Research.
The main conclusion of the meeting was that a global deterioration of climate, by order of magnitude larger than any hitherto experience by civilized mankind, is a very real possibility and indeed may be due very soon.
The cooling has natural cause and falls within the rank of processes which produced the last ice age. This is a surprising result based largely on recent studies of deep sea sediments.
Existing data still do not allow forecast of the precise timing of the predicted development, nor the assessment of the man’s interference with the natural trends. It could not be excluded however that the cooling now under way in the Northern Hemisphere is the start of the expected shift. The present rate of the cooling seems fast enough to bring glacial temperatures in about a century, if continuing at the present pace.
The practical consequences which might be brought by such developments to existing social institution are among others:
(1) Substantially lowered food production due to the shorter growing seasons and changed rain distribution in the main grain producing belts of the world, with Eastern Europe and Central Asia to be first affected.
(2) Increased frequency and amplitude of extreme weather anomalies such as those bringing floods, snowstorms, killing frosts, etc.
With the efficient help of the world leaders, the research …
With best regards,
George J. Kukla (Lamont-Doherty Geological Observatory)
R. K. Matthews (Chairman, Dept of Geological Sciences, Brown U)
The White House assigned the task of looking at the claims contained in the letter to its science agencies, especially the National Science Foundation and NOAA, who engaged in a flurry of activity looking into the threat of an ice age.
On August 1, 1974 the White House wrote a letter to Secretary of Commerce Frederick Dent stating:
Changes in climate in recent years have resulted in unanticipated impacts on key national programs and policies. Concern has been expressed that recent changes may presage others. In order to assess the problem and to determine what concerted action ought to be undertaken, I have decided to establish a subcommittee on Climate Change.
Out of this concern, the U.S. government started monitoring climate.
As NOAA scientists Robert W. Reeves, Daphne Gemmill, Robert E. Livezey, and James Laver point out:
There were also a number of short-term climate events of national and international consequence in the early 1970s that commanded a certain level of attention in Washington. Many of them were linked to the El Niño of 1972-1973.
A killing winter freeze followed by a severe summer heat wave and drought produced a 12 percent shortfall in Russian grain production in 1972. The Soviet decision to offset the losses by purchase abroad reduced world grain reserves and helped drive up food prices.Collapse of the Peruvian anchovy harvest in late 1972 and early 1973, related to fluctuations in the Pacific ocean currents and atmospheric circulation, impacted world supplies of fertilizer, the soybean market, and prices of all other protein feedstocks.
The anomalously low precipitation in the U.S. Pacific north-west during the winter of 1972-73 depleted reservoir storage by an amount equivalent to more than 7 percent of the electric energy requirements for the region.
On June 24, 1974, Time Magazine wrote an article entitled “Another Ice Age?” which stated:
As they review the bizarre and unpredictable weather pattern of the past several years, a growing number of scientists are beginning to suspect that many seemingly contradictory meteorological fluctuations are actually part of a global climatic upheaval. However widely the weather varies from place to place and time to time, when meteorologists take an average of temperatures around the globe they find that the atmosphere has been growing gradually cooler for the past three decades. The trend shows no indication of reversing. Climatological Cassandras are becoming increasingly apprehensive, for the weather aberrations they are studying may be the harbinger of another ice age.
Telltale signs are everywhere …
Whatever the cause of the cooling trend, its effects could be extremely serious, if not catastrophic. Scientists figure that only a 1% decrease in the amount of sunlight hitting the earth’s surface could tip the climatic balance, and cool the planet enough to send it sliding down the road to another ice age within only a few hundred years.
(here’s the printer-friendly version).
Science News wrote an article in 1975 called “Chilling Possibilities” warning of a new ice age.
A January 1975 article from the New York Times warned:
The most drastic potential change considered in the new report (by the National Academy of Sciences) is an abrupt end to the present interglacial period of relative warmth that has governed the planet’s climate for the past 10,000 years.
On April 28, 1975, Newsweek wrote an article stating:
Climatologists are pessimistic that political leaders will take any positive action to compensate for the climatic change, or even to allay its effects. They concede that some of the more spectacular solutions proposed, such as melting the Arctic ice cap by covering it with black soot or diverting arctic rivers, might create problems far greater than those they solve. But the scientists see few signs that government leaders anywhere are even prepared to take the simple measures of stockpiling food or of introducing the variables of climatic uncertainty into economic projections of future food supplies. The longer the planners delay, the more difficult will they find it to cope with climatic change once the results become grim reality.
Here is a reprint of the article in the Washington Times, and here is a copy of the 1975 Newsweek article.
Newsweek discussed its 1975 article in 2006:
In April, 1975 … NEWSWEEK published a small back-page article about a very different kind of disaster. Citing “ominous signs that the earth’s weather patterns have begun to change dramatically,” the magazine warned of an impending “drastic decline in food production.” Political disruptions stemming from food shortages could affect “just about every nation on earth.” Scientists urged governments to consider emergency action to head off the terrible threat of . . . well, if you had been following the climate-change debates at the time, you’d have known that the threat was: global cooling…
Citizens can judge for themselves what constitutes a prudent response-which, indeed, is what occurred 30 years ago. All in all, it’s probably just as well that society elected not to follow one of the possible solutions mentioned in the NEWSWEEK article: to pour soot over the Arctic ice cap, to help it melt.
New York Times science columnist John Tierney noted in 2009:
In 1971, long before Dr. Holdren came President Obama’s science adviser, in an essay [titled] “Overpopulation and the Potential for Ecocide,” Dr. Holdren and his co-author, the ecologist Paul Ehrlich, warned of a coming ice age.
They certainly weren’t the only scientists in the 1970s to warn of a coming ice age, but I can’t think of any others who were so creative in their catastrophizing. Although they noted that the greenhouse effect from rising emissions of carbon dioxide emissions could cause future warming of the planet, they concluded from the mid-century cooling trend that the consequences of human activities (like industrial soot, dust from farms, jet exhaust, urbanization and deforestation) were more likely to first cause an ice age. Dr. Holdren and Dr. Ehrlich wrote:
The effects of a new ice age on agriculture and the supportability of large human populations scarcely need elaboration here. Even more dramatic results are possible, however; for instance, a sudden outward slumping in the Antarctic ice cap, induced by added weight, could generate a tidal wave of proportions unprecedented in recorded history.
A May 21, 1975 article in the New York Times again stated:
Sooner or later a major cooling of the climate is widely considered inevitable.
The American Institute of Physics – the organization mentioned in the Boston Globe article – notes:
For a few years in the early 1970s, new evidence and arguments led many scientists to suspect that the greatest climate risk was not warming, but cooling. A new ice age seemed to be approaching as part of the natural glacial cycle, perhaps hastened by human pollution that blocked sunlight. Technological optimists suggested ways to counter this threat too. We might spread soot from cargo aircraft to darken the Arctic snows, or even shatter the Arctic ice pack with “clean” thermonuclear explosions.
***
The bitter fighting among communities over cloud-seeding would be as nothing compared with conflicts over attempts to engineer global climate. Moreover, as Budyko and Western scientists alike warned, scientists could not predict the consequences of such engineering efforts. We might forestall global warming only to find we had triggered a new ice age.
A 1994 Time article entitled “The Ice Age Cometh?” stated:
What ever happened to global warming? Scientists have issued apocalyptic warnings for years, claiming that gases from cars, power plants and factories are creating a greenhouse effect that will boost the temperature dangerously over the next 75 years or so. But if last week is any indication of winters to come, it might be more to the point to start worrying about the next Ice Age instead. After all, human-induced warming is still largely theoretical, while ice ages are an established part of the planet’s history. The last one ended about 10,000 years ago; the next one — for there will be a next one — could start tens of thousands of years from now. Or tens of years. Or it may have already started.
The Register reported last year:
What may be the science story of the century is breaking this evening, as heavyweight US solar physicists announce that the Sun appears to be headed into a lengthy spell of low activity, which could mean that the Earth – far from facing a global warming problem – is actually headed into a mini Ice Age.
sunspot decline Top Scientists, Government Agencies and Publications Have For Over 100 Years Been Terrified of a New Ice Age
***
The announcement made on 14 June (18:00 UK time) comes from scientists at the US National Solar Observatory (NSO) and US Air Force Research Laboratory. Three different analyses of the Sun’s recent behaviour all indicate that a period of unusually low solar activity may be about to begin.
***
This could have major implications for the Earth’s climate. According to a statement issued by the NSO, announcing the research:
An immediate question is whether this slowdown presages a second Maunder Minimum, a 70-year period with virtually no sunspots [which occurred] during 1645-1715.
As NASA notes:
Early records of sunspots indicate that the Sun went through a period of inactivity in the late 17th century. Very few sunspots were seen on the Sun from about 1645 to 1715. Although the observations were not as extensive as in later years, the Sun was in fact well observed during this time and this lack of sunspots is well documented. This period of solar inactivity also corresponds to a climatic period called the “Little Ice Age” when rivers that are normally ice-free froze and snow fields remained year-round at lower altitudes. There is evidence that the Sun has had similar periods of inactivity in the more distant past.
During the Maunder Minimum and for periods either side of it, many European rivers which are ice-free today – including the Thames – routinely froze over, allowing ice skating and even for armies to march across them in some cases.
“This is highly unusual and unexpected,” says Dr Frank Hill of the NSO. “But the fact that three completely different views of the Sun point in the same direction is a powerful indicator that the sunspot cycle may be going into hibernation.”
***
According to the NSO:
Penn and Livingston observed that the average field strength declined about 50 gauss per year during Cycle 23 and now in Cycle 24. They also observed that spot temperatures have risen exactly as expected for such changes in the magnetic field. If the trend continues, the field strength will drop below the 1,500 gauss threshold and spots will largely disappear as the magnetic field is no longer strong enough to overcome convective forces on the solar surface.
In parallel with this comes research from the US Air Force’s studies of the solar corona.
***
“Cycle 24 started out late and slow and may not be strong enough to create a rush to the poles, indicating we’ll see a very weak solar maximum in 2013, if at all. If the rush to the poles fails to complete, this creates a tremendous dilemma for the theorists … No one knows what the Sun will do in that case.”
According to the collective wisdom of the NSO, another Maunder Minimum may very well be on the cards.
“If we are right,” summarises Hill, “this could be the last solar maximum we’ll see for a few decades. That would affect everything from space exploration to Earth’s climate.”
***
The big consequences of a major solar calm spell, however, would be climatic. The next few generations of humanity might not find themselves trying to cope with global warming but rather with a significant cooling. This could overturn decades of received wisdom on such things as CO2 emissions, and lead to radical shifts in government policy worldwide.
And Agence France-Presse reports:
For years, scientists have been predicting the Sun would by around 2012 move into solar maximum, a period of intense flares and sunspot activity, but lately a curious calm has suggested quite the opposite.
According to three studies released in the United States on Tuesday, experts believe the familiar sunspot cycle may be shutting down and heading toward a pattern of inactivity unseen since the 17th century.
The signs include a missing jet stream, fading spots, and slower activity near the poles, said experts from the National Solar Observatory and Air Force Research Laboratory.
“This is highly unusual and unexpected,” said Frank Hill, associate director of the NSO’s Solar Synoptic Network, as the findings of the three studies were presented at the annual meeting of the American Astronomical Society’s Solar Physics Division in Las Cruces, New Mexico.
“But the fact that three completely different views of the Sun point in the same direction is a powerful indicator that the sunspot cycle may be going into hibernation.”
Solar activity tends to rise and fall every 11 years or so. The solar maximum and solar minimum each mark about half the interval of the magnetic pole reversal on the Sun, which happens every 22 years.
Hill said the current cycle, number 24, “may be the last normal one for some time and the next one, cycle 25, may not happen for some time.
“This is important because the solar cycle causes space weather which affects modern technology and may contribute to climate change,” he told reporters.
Experts are now probing whether this period of inactivity could be a second Maunder Minimum, which was a 70-year period when hardly any sunspots were observed between 1645-1715, a period known as the “Little Ice Age.”
“If we are right, this could be the last solar maximum we’ll see for a few decades. That would affect everything from space exploration to Earth’s climate,” said Hill.
And the Wall Street Journal wrote in January:
The entire 10,000-year history of civilization has happened in an unusually warm interlude in the Earth’s recent history. Over the past million years, it has been as warm as this or warmer for less than 10% of the time, during 11 brief episodes known as interglacial periods. [In other words, the Earth is in an ice age most of the time, and that the warmer "interglacial" periods are rare.] One theory holds that agriculture and dense settlement were impossible in the volatile, generally dry and carbon-dioxide-starved climates of the ice age, when crop plants would have grown more slowly and unpredictably even in warmer regions.
This warm spell is already 11,600 years old, and it must surely, in the normal course of things, come to an end. In the early 1970s, after two decades of slight cooling, many scientists were convinced that the moment was at hand. They were “increasingly apprehensive, for the weather aberrations they are studying may be the harbinger of another ice age,” said Time in 1974. The “almost unanimous” view of meteorologists was that the cooling trend would “reduce agricultural productivity for the rest of the century,” and “the resulting famines could be catastrophic,” said Newsweek in 1975.
Since then, of course, warmth has returned, probably driven at least partly by man-made carbon-dioxide emissions. A new paper, from universities in Cambridge, London and Florida, drew headlines last week for arguing that these emissions may avert the return of the ice age. Less noticed was the fact that the authors, by analogy with a previous warm spell 780,000 years ago that’s a “dead ringer” for our own, expect the next ice age to start “within about 1,500 years.” Hardly the day after tomorrow.
Still, it’s striking that most interglacials begin with an abrupt warming, peak sharply, then begin a gradual descent into cooler conditions before plunging rather more rapidly toward the freezer. The last interglacial—which occurred 135,000 to 115,000 years ago (named the Eemian period after a Dutch river near which the fossils of warmth-loving shell creatures of that age were found)—saw temperatures slide erratically downward by about two degrees Celsius between 127,000 and 120,000 years ago, before a sharper fall began.
Cyclical changes in the earth’s orbit probably weakened sunlight in the northern hemisphere summer and thus caused this slow cooling. Since the northern hemisphere is mostly land, this change in the sun’s strength meant gradually increased snow and ice cover, which in turn reflected light back into space. This would have further cooled the air and, gradually, the ocean too. Carbon-dioxide levels did not begin to fall much until about 112,000 years ago, as the cooling sea absorbed more of the gas.
Our current interglacial shows a similar pattern. Greenland ice cores and other proxy records show that temperatures peaked around 7,000 years ago, when the Arctic Ocean was several degrees warmer than today, trees grew farther north in Siberia and the Sahara was wet enough for hippos (Africa generally gets wetter in warm times). Data from the southern hemisphere reveal that this “Holocene Optimum” was global in extent.
An erratic decline in temperature followed, with Minoan, Roman and Medieval warm periods peaking at successively lower temperatures, culminating in the exceptionally cool centuries of the “Little Ice Age” between 1550 and 1850, when glaciers advanced all over the world. In the Greenland ice cores, these centuries stand out as the longest and most consistent cold spell of the current interglacial.
In other words, our own interglacial period has followed previous ones in having an abrupt beginning and a sharp peak, followed by slow cooling. The question is whether recent warming is a temporary blip before the expected drift into glacial conditions, or whether humankind’s impact on the atmosphere has now reversed the cooling trend.
--- Fin de la cita ---
Básicamente, el artículo dice que, antes de que se pusiera de moda la tesis del calentamiento global, la mayoría de los científicos temía que se produjera un enfriamiento global. Se apoyaban en estudios de historia mundial del clima terrestre y en la evolución de los ciclos de las manchas solares, que reflejan la potencia de la radiación solar que llega a la tierra.
P.D.: Si hay otro hilo abierto y no lo he visto, ruego a Aire que mueva éste al hilo antiguo. :)
http://www.washingtonsblog.com/2012/04/top-scientists-government-agencies-and-publications-have-for-over-100-years-feared-an-ice-age.html
Currobena:
Consecuencias de la variación climática en nuestros ríos: sequía en abril.
--- Citar ---Sufren la sequía de forma particular Miño-Sil, Duero y Tajo
El caudal de los ríos españoles ha descendido casi un 70%
La escasez de lluvias está afectando de manera muy significativa en el último año a las cuencas de los grandes ríos
Periodista Digital, 16 de abril de 2012 a las 14:05
Falta de agua y sequía persistente.
El caudal de los principales ríos españoles ha descendido un 69,4% en los últimos doce meses debido a la escasez de lluvias, según datos del Ministerio de Agricultura, Alimentación y Medio Ambiente.
La cantidad de metros cúbicos de agua por segundo que recorren las estaciones de medición instaladas en las distintas cuencas hidrográficas se ha reducido de 5.060 metros cúbicos a 1.548 desde abril de 2011 hasta la actualidad.
Las cuencas que se han resentido más por la falta de precipitaciones durante los últimos meses son las del Miño-Sil, Duero y Tajo, cuyos caudales, a su paso por las estaciones de medición, han bajado cerca de un 80%.
Miño-Sil
El río Miño a su paso por el embalse de Frieira (Pontevedra) transcurre con un caudal de 71,6 metros cúbicos por segundo, un 79% menos que hace justo un año.
Duero
La cuenca del Duero ha visto rebajado su caudal un 79,3%, si se tienen en cuenta los datos que recogen las 17 estaciones de medición situadas en varios puntos de los cauces que la forman.
El río Duero ha bajado un 84% a su paso por Toro (Zamora), pasando de los 210 metros cúbicos por segundo en abril de 2011 a los 33 que se registran hoy.
En la misma cuenca, el caudal del río Pisuerga también ha descendido a casi la mitad, situación que se evidencia especialmente en la capital vallisoletana, donde la cantidad de metros cúbicos por segundo se ha recortado un 75%; de los 76 a los 19.
Tajo
El Tajo registra un caudal nulo a su paso por varias estaciones de medición, como ocurre en Alcántara, Torrejón y Valdecañas, todas ellas en la provincia de Cáceres. Si bien es cierto que aumenta un 27% a su paso por Bolarque (Cuenca).
En conjunto, el caudal de los ríos que forman parte de la cuenca del Tajo ha descendido de 843 metros cúbicos por segundo a los 182 en los últimos doce meses, lo que representa un descenso de un 78,3%.
Segura
Las dos estaciones de medición en Almadenes (Murcia) y en Rojales (Alicante) reflejan un aumento del caudal de un 1,6%, convirtiéndose, de esta manera, en la única cuenca que no pierde metros cúbicos de agua en lo que va de 2012.
Cuenca cantábrica
Tampoco registra mucha variación el caudal de la cuenca cantábrica, donde muchas de las estaciones medidoras evidencian un aumento de metros cúbicos, como es el caso del río Besaya a su paso por Torrelavega (Cantabria), que ha aumentado un 76,5%, mientras que el Urumea a su paso por Ereñozu (Guipúzcoa) ha descendido un 70%.
Guadiana
La cuenca del Guadiana registra un descenso acusado (un 67%), especialmente a su paso por Badajoz, donde la cantidad de metros cúbicos ha bajado de los 34 a los 11.
Mediterránea andaluza
La cuenca del Guadalquivir disminuye un 58%, según reflejan los medidores en Mengíbar (Jaén) y en la presa de Alcalá del Río (Sevilla), mientras que el río Genil, que abastece a la cuenca del Guadalquivir, ha aumentado su caudal a su paso por Écija (Sevilla) un 75%.
Ebro
El caudal en la cuenca del Ebro desciende un 55%, mientras que las cuencas internas de Cataluña y la cuenca del Júcar disminuyen un 18 y un 7% respectivamente.
--- Fin de la cita ---
Combinado el efecto del clima y la consiguiente falta de agua con la intervención de este verano y la más que posible privatización del agua pública para los amiguetes, aquí tenemos una bomba de relojería. :(
http://www.periodistadigital.com/ciencia/medioambiente/2012/04/16/el-caudal-de-los-rios-espanoles-ha-descendido-casi-un-70-.shtml
Starkiller:
Que el tema del cambio climático ha sido totalmente politizado estos últimos 15 años es un hecho. Que aquellos investigadores que argumentaban a su favor han sido subsidiados, y que los que encabezaban estudios que ponían en duda las tésis del IPCC han sido apartados, es algo que también se sabe.
Los intereses han sido múltiples: kyoto ha sido una herramienta para bloquear a ciertas potencias emergentes, y para colaborar en el control del pastel global. El intento de renacimiento de la energía nuclear, libre de emisiones según los parámetros de kyoto, era otro objetivo. El premio de consolación que se le ofreció a Al Gore ha sido un negocio en toda regla, como tantos.
Solo ahora que USA (O ciertos grupos de interés repartidos entre diversas potencias, mejor dicho) ha podido imponer su estrategia de control global de los mercados de petróleo, deja de ser necesaria, y comienza a abandonarse, con lo que noticias como estas comienzan a hacerse públicas. También la pérdida de apoyo de la energía nuclear por parte de potencias ayuda mucho a esto.
En efecto, en términos generales, lo que se teme es que nos acerquemos a otra era glacial. Los tiempos, dentro de esos ciclos de 100.000 años, encajan. Huelga decir que no se sabe si estamos a 1000 o a 5000 años de dicho evento, pero la evidencia geológica es incondestable.
Acerca de los ciclos climáticos mas cortos, la evidencia actual es que existe una correlación casi exacta con los ciclos solares. Se ignora el mecanismo por el que estos afectan el clima (Dadoq ue no ha habido interés ni fondos para averiguarlo), pero los datos están ahí, y on son difícils de comprobar.
Yo nunca he considerado creíble la teoría del cambio climático antropocéntrico. Que el clima cambia es un hecho; que sea causado por el hombre, para mi, es muy dudoso. Eso sin contar ocn la inmensa capacidad regenerativa de la tierra y de la vida en general. Conste que cuando hablo de esto, me refiero a los gases invernadero; asuntos como fukushima, o la extinción de especies son muy diferentes, y si son inmensamente preocupantes.
Currobena:
--- Cita de: Starkiller en Abril 17, 2012, 11:47:10 am ---Que el tema del cambio climático ha sido totalmente politizado estos últimos 15 años es un hecho. Que aquellos investigadores que argumentaban a su favor han sido subsidiados, y que los que encabezaban estudios que ponían en duda las tésis del IPCC han sido apartados, es algo que también se sabe.
Los intereses han sido múltiples: kyoto ha sido una herramienta para bloquear a ciertas potencias emergentes, y para colaborar en el control del pastel global. El intento de renacimiento de la energía nuclear, libre de emisiones según los parámetros de kyoto, era otro objetivo. El premio de consolación que se le ofreció a Al Gore ha sido un negocio en toda regla, como tantos.
Solo ahora que USA (O ciertos grupos de interés repartidos entre diversas potencias, mejor dicho) ha podido imponer su estrategia de control global de los mercados de petróleo, deja de ser necesaria, y comienza a abandonarse, con lo que noticias como estas comienzan a hacerse públicas. También la pérdida de apoyo de la energía nuclear por parte de potencias ayuda mucho a esto.
En efecto, en términos generales, lo que se teme es que nos acerquemos a otra era glacial. Los tiempos, dentro de esos ciclos de 100.000 años, encajan. Huelga decir que no se sabe si estamos a 1000 o a 5000 años de dicho evento, pero la evidencia geológica es incondestable.
Acerca de los ciclos climáticos mas cortos, la evidencia actual es que existe una correlación casi exacta con los ciclos solares. Se ignora el mecanismo por el que estos afectan el clima (Dadoq ue no ha habido interés ni fondos para averiguarlo), pero los datos están ahí, y on son difícils de comprobar.
Yo nunca he considerado creíble la teoría del cambio climático antropocéntrico. Que el clima cambia es un hecho; que sea causado por el hombre, para mi, es muy dudoso. Eso sin contar ocn la inmensa capacidad regenerativa de la tierra y de la vida en general. Conste que cuando hablo de esto, me refiero a los gases invernadero; asuntos como fukushima, o la extinción de especies son muy diferentes, y si son inmensamente preocupantes.
--- Fin de la cita ---
Tampoco creo que se solamente causado por el hombre. Sin embargo, dada la escala que está adquiriendo la huella humana en todo el mundo, si creo posible que esté parcialmente influido por el hombre. Ahora, hasta qué punto pesa más una cosa u otra exigiría una investigación amplia y rigurosa.
La extinción de especies es un fenómeno natural, lo que no es tan natural es la velocidad a la que se están extinguiendo recientemente (cuando digo recientemente, hablo en términos geológicos, de los últimos 50000 años, más o menos). Ahí si creo que nosotros somos los principales responsables.
De Fukushima poco hay que añadir del otro hilo, y coincido contigo en que es muchísimo más importante de lo que piensa la mayoría por ahora. Confío en que cambie en un futuro próximo, o podríamos vernos abocados a problemas muy graves, llegando incluso al riesgo de extinción de la especie humana.
traspotin:
@Starkiller
--- Cita de: Starkiller en Abril 17, 2012, 11:47:10 am ---Que el tema del cambio climático ha sido totalmente politizado estos últimos 15 años es un hecho.
--- Fin de la cita ---
En efecto ha sido muy politizada pero no en el sentido que quieres expresar sino más bien todo lo contrario. Ya sabemos que las empresas privadas no van a poner ni un duro para investigar el cambio climático antropogénico (si no es para desmentirlo), al igual que ninguna empresa privada va a mejorar la eficiencia del mercado, sino más bien lo contrario, lo que quiere es monopolizarlo, como muy bien has expresado en otros hilos.
--- Citar ---Que aquellos investigadores que argumentaban a su favor han sido subsidiados, y que los que encabezaban estudios que ponían en duda las tésis del IPCC han sido apartados, es algo que también se sabe.
--- Fin de la cita ---
Hombre es que no van a pagar de su bolsillo los estudios que afectan a todo el ecosistema mundial. Parecería más bien que quieres indicar que ha habido una purga y lo que hay es más bien lo contrario. Las empresas energéticas están inundando literalmente de petrodólares a unos pocos investigadores para que estén en contra del calentamiento global, o sea que los resultados de esos "estudios" (en algunos casos no llegan ni a eso), están escritos de antemano y son directamente proporcionales a la cantidad de petrodólares con los que se pagan.
--- Citar ---Los intereses han sido múltiples: kyoto ha sido una herramienta para bloquear a ciertas potencias emergentes, y para colaborar en el control del pastel global. El intento de renacimiento de la energía nuclear, libre de emisiones según los parámetros de kyoto, era otro objetivo. El premio de consolación que se le ofreció a Al Gore ha sido un negocio en toda regla, como tantos.
--- Fin de la cita ---
Aquí ya no entro porque la verdad es que no tengo ni idea de geopolítica pero los hechos de Fukushima y que Japón cierre todas sus nucleares y la ciencia a mi parecer indicarían lo contrario.
--- Citar ---Solo ahora que USA (O ciertos grupos de interés repartidos entre diversas potencias, mejor dicho) ha podido imponer su estrategia de control global de los mercados de petróleo, deja de ser necesaria, y comienza a abandonarse, con lo que noticias como estas comienzan a hacerse públicas. También la pérdida de apoyo de la energía nuclear por parte de potencias ayuda mucho a esto.
--- Fin de la cita ---
No entiendo muy bien, qué noticia? Realmente piensas que esto es una noticia? pero si sólo hay que leerla para ver que lo que expresa es un punto de vista. Habla de un "intenso debate" para luego referirse a un par de científicos(geólogos por cierto, no dice que sean climatólogos), a una noticia del NYT(por cierto de 1985) y otra del WP del 70 (como si nos hubiéramos enfriado desde entonces jeje), al NOAA diciendo que tiene que estudiarse este aspecto (sin embargo sólo hay que irse a lo que dice actualmente el NOAA) y la mejor de todas...una artículo de la revista TIME!! porque claro es una revista científica reputadísima (no un magazine) y es rarísimo que prácticamente todas las fechas sean de los 70.
--- Citar ---En efecto, en términos generales, lo que se teme es que nos acerquemos a otra era glacial. Los tiempos, dentro de esos ciclos de 100.000 años, encajan. Huelga decir que no se sabe si estamos a 1000 o a 5000 años de dicho evento, pero la evidencia geológica es incondestable.
--- Fin de la cita ---
No Starkiller, en todo caso será lo que tú temes, no lo que la comunidad científica piensa.
--- Citar ---Acerca de los ciclos climáticos mas cortos, la evidencia actual es que existe una correlación casi exacta con los ciclos solares. Se ignora el mecanismo por el que estos afectan el clima (Dadoq ue no ha habido interés ni fondos para averiguarlo), pero los datos están ahí, y on son difícils de comprobar.
--- Fin de la cita ---
Exactamente a que ciclos te refieres? Los datos están ahí y al contrario de lo que comentas son fáciles de comprobar.
--- Citar ---Yo nunca he considerado creíble la teoría del cambio climático antropocéntrico. Que el clima cambia es un hecho; que sea causado por el hombre, para mi, es muy dudoso. Eso sin contar ocn la inmensa capacidad regenerativa de la tierra y de la vida en general. Conste que cuando hablo de esto, me refiero a los gases invernadero; asuntos como fukushima, o la extinción de especies son muy diferentes, y si son inmensamente preocupantes.
--- Fin de la cita ---
Pues yo creo que no es dudoso en absoluto y que está muy sólidamente demostrada la teoría. La inmensa capacidad regenerativa de la Tierra no es que esté en cuestión, es que puede estar en peligro, sólo hay que ver lo que pasa en Venus.
@Currobena
--- Citar ---Básicamente, el artículo dice que, antes de que se pusiera de moda la tesis del calentamiento global, la mayoría de los científicos temía que se produjera un enfriamiento global. Se apoyaban en estudios de historia mundial del clima terrestre y en la evolución de los ciclos de las manchas solares, que reflejan la potencia de la radiación solar que llega a la tierra.
--- Fin de la cita ---
Pues yo no entiendo eso. Lo que yo entiendo es que se presenta un reportaje donde se indicaba que los registros paleoclimáticos parecen indicar que vamos a un enfriamiento, no que hubiera consenso científico en los 70 en cuanto al posible enfriamiento de la Tierra (el consenso científico de la época indicaba lo contrario, que se calentaría como bien ha pasado y se puede demostrar). Otra cosa distinta es que haya una variabilidad natural en el ciclo climático de la Tierra y que los registros fósiles pudieran indicar que en realidad esa variabilidad natural actualmente vaya hacia un enfriamiento natural, cosa que es muy posible que sea cierta (ver ciclos de Milankovitch en función de la posición orbital). Pero sinceramente, los que esperen una nueva glaciación con la cantidad de co2 que hay y que sigue aumentando en la atmósfera, pueden esperar sentados, porque ocurrirá exactamente lo contrario.
Saludos y perdón por responder tan tarde pero no es que tenga mucho tiempo la verdad.
Navegación
[#] Página Siguiente
Ir a la versión completa