Cambio climático: debates varios

Global Temps Plunged 1-2°C Within Decades 8.2 K and 4.2 K Years Ago – And It Could Happen Again

In direct contrast with CO2-centric climate modeling, extensive paleoclimate evidence affirms that the Holocene climate has been far more variable in the past 12,000 years than during the relatively quiescent period we’ve enjoyed since the mid-19th century. In the absence of CO2 concentration changes or human interference, abrupt global cooling episodes led to agricultural collapse, famines, and the extirpation of ancient civilizations.  These naturally-occurring climate events are likely to recur…and we will be powerless to intervene.
Climate Modeling Rooted In CO2-Driven Temperature Change Cannot Reproduce This Variability

 

Sham Predictions By NASA, NSIDC, U of Cambridge, VP Al Gore, Sen. John Kerry Exposed

Charlatans exposed…when sham predictions clash with reality







 

Os dejo un enlace, vemos que según los últimos estudios, no hace falta que el hombre genere grandes cantidades de CO2 para que exista un aumento, de forma natural.

https://doi.pangaea.de/10.1594/PANGAEA.892203

Article | Published: 13 August 2018

Flushing of the deep Pacific Ocean and the deglacial rise of atmospheric CO2 concentrations
Jianghui Du, Brian A. Haley, Alan C. Mix, Maureen H. Walczak & Summer K. Praetorius
Nature Geoscience (2018) | Download Citation

Abstract
During the last deglaciation (19,000–9,000 years ago), atmospheric CO2 increased by about 80 ppm. Understanding the mechanisms responsible for this change is a central theme of palaeoclimatology, relevant for predicting future CO2 transfers in a warming world. Deglacial CO2 rise hypothetically tapped an accumulated deep Pacific carbon reservoir, but the processes remain elusive as they are underconstrained by existing tracers. Here we report high-resolution authigenic neodymium isotope data in North Pacific sediment cores and infer abyssal Pacific overturning weaker than today during the Last Glacial Maximum but intermittently stronger during steps of deglacial CO2 rise. Radiocarbon evidence suggestive of relatively ‘old’ deglacial deep Pacific water is reinterpreted here as an increase in preformed 14C age of subsurface waters sourced near Antarctica, consistent with movement of aged carbon out of the deep ocean and release of CO2 to the atmosphere during the abyssal flushing events. The timing of neodymium isotope changes suggests that deglacial acceleration of Pacific abyssal circulation tracked Southern Hemisphere warming, sea-ice retreat and increase of mean ocean temperature. The inferred magnitude of circulation changes is consistent with deep Pacific flushing as a significant, and perhaps dominant, control of the deglacial rise of atmospheric CO2.

http://www.iodp.org/

The Physical Flaws of the Global Warming Theory and Deep Ocean Circulation Changes as the Primary Climate Driver

Increases in CO2 and other greenhouse gases will not be able to bring about significant climate
disruption in the next 75-100 years. The main problem with the Anthropogenic Global Warming
(AGW) theory is the false treatment of the global hydrologic cycle which is not adequately understood by any of the AGW advocates.
The water vapor, cloud, and condensation-evaporation assumptions within the conventional AGW theory and the (GCM) simulations are incorrectly designed to block too much infrared (IR) radiation to space. They also do not reflect-scatter enough short wave (albedo) energy to space. These two misrepresentations result in a large artificial warming that is not realistic.
A realistic treatment of the hydrologic cycle would show that the influence of a doubling of CO2 should lead to a global surface warming of only about 0.3°C – not the 3°C warming as indicated by the climate simulations.

 

Os dejo un enlace, vemos que según los últimos estudios, no hace falta que el hombre genere grandes cantidades de CO2 para que exista un aumento, de forma natural.

https://doi.pangaea.de/10.1594/PANGAEA.892203

Article | Published: 13 August 2018

Flushing of the deep Pacific Ocean and the deglacial rise of atmospheric CO2 concentrations
Jianghui Du, Brian A. Haley, Alan C. Mix, Maureen H. Walczak & Summer K. Praetorius
Nature Geoscience (2018) | Download Citation

Abstract
During the last deglaciation (19,000–9,000 years ago), atmospheric CO2 increased by about 80 ppm. Understanding the mechanisms responsible for this change is a central theme of palaeoclimatology, relevant for predicting future CO2 transfers in a warming world. Deglacial CO2 rise hypothetically tapped an accumulated deep Pacific carbon reservoir, but the processes remain elusive as they are underconstrained by existing tracers. Here we report high-resolution authigenic neodymium isotope data in North Pacific sediment cores and infer abyssal Pacific overturning weaker than today during the Last Glacial Maximum but intermittently stronger during steps of deglacial CO2 rise. Radiocarbon evidence suggestive of relatively ‘old’ deglacial deep Pacific water is reinterpreted here as an increase in preformed 14C age of subsurface waters sourced near Antarctica, consistent with movement of aged carbon out of the deep ocean and release of CO2 to the atmosphere during the abyssal flushing events. The timing of neodymium isotope changes suggests that deglacial acceleration of Pacific abyssal circulation tracked Southern Hemisphere warming, sea-ice retreat and increase of mean ocean temperature. The inferred magnitude of circulation changes is consistent with deep Pacific flushing as a significant, and perhaps dominant, control of the deglacial rise of atmospheric CO2.

http://www.iodp.org/

Parece un artículo interesante (solo he podio leer el resumen) que sería totalmente coherente con la secuencia de deglaciación típicamente establecida:
1. Variación orbital y/o del eje terrestre.
2. Aumento relativo de la temperatura global.
3. Liberación de CO2 oceánico procedente, sobre todo, de aguas profundas (por aceleración de circulación e intercambio gaseoso).
4. Amplificación del calentamiento global por efecto invernadero.

De ahí que el aumento de CO2 en una deglaciación siga al aumento de temperatura inicial con un cierto retraso (menor de lo que se pensaba hace años). Un proceso totalmente natural sin intervención humana, como es obvio.

En el reciente CGA lo que sucede es que las emisiones de GEIs antropogénicas sustituyen el punto 3 y provocan el punto 4 sin intervención significativa del punto 1 o de cualquier otro mecanismo natural (actividad solar, volcanes, etc.).

Harmonic Analysis of Worldwide Temperature Proxies for 2000 Years

ABSTRACT

The Sun as climate driver is repeatedly discussed in the literature but proofs are often weak.
In order to elucidate the solar influence, we have used a large number of temperature proxies worldwide to construct a global temperature mean G7 over the last 2000 years.
The Fourier spectrum of G7 shows the strongest components as ~1000-, ~460-, and ~190 - year periods whereas other cycles of the individual proxies are considerably weaker. The G7 temperature extrema coincide with the Roman, medieval, and present optima as well as the well-known minimum of AD 1450 during the Little Ice Age.
We have constructed by reverse Fourier transform a representation of G7 using only these three sine functions, which shows a remarkable Pearson correlation of 0.84 with the 31-year running average of G7. The three cycles are also found dominant in the production rates of the solar-induced cosmogenic nuclides 14C and 10Be, most strongly in the ~190 - year period being known as the De Vries/Suess cycle.
By wavelet analysis, a new proof has been provided that at least the ~190-year climate cycle has a solar origin.

DISCUSSION / CONCLUSION

The Fourier spectrum of a global temperature record G7, composed of high quality temperature proxies worldwide and recent instrumental data demonstrate the dominance of three climate cycles with ~1000 (Eddy cycle), ~460 (not named but frequently reported), and ~190 year periods (De Vries/Suess cycle). These three sines represent the 31-year running mean of G7 with the remarkable Pearson correlation of 0.84 indicating their importance for climate.
G7, and likewise the sine representations have maxima of comparable size at AD 0, 1000, and 2000. We note that the temperature increase of the late 19th and 20th century is represented by the harmonic temperature representation, and thus is of pure multiperiodic nature.
It can be expected that the periodicity of G7, lasting 2000 years so far, will persist also for the foreseeable future. It predicts a temperature drop from present to AD 2050, a slight rise from 2050 to 2130, and a further drop from AD 2130 to 2200 (see Fig. 3), upper panel, green and red curves).
As a main result of our study, the construction of a global record G7 from numerous temperature proxies reduces noise and thus allows the isolation of these global cycles. The dominance of the significant frequency components in the G7 spectrum, as opposed to the strength of other components in the spectra of the individual proxy records supports this view.
We provide a new confirmation for the link between solar activity and climate cycles by wavelet analysis showing a remarkably good agreement of the power of the ~190 - year period for temperatures and solar activity over 9000 years (see Fig. 4 lower panel). As (Fig. 2 and Table 2) show, the periods of ~1000 and ~460 years are also apparently common in records of temperatures and cosmogenic nuclides. 




 

Sic transit historia mundi...



 

Sic transit historia mundi...



 

Sería estúpido negar que la bonanza climática (no necesariamente el calor) favorece el desarrollo de las sociedades, particularmente de las agropecuarias preindustriales. Pero desde luego no es el único, ni a veces el más importante, factor que explica el florecimiento u ocaso de las civilizaciones. La realidad suele ser más compleja. Por eso, es más que discutible intentar reflejar la evolución histórica de los últimos siglos en base a un localismo (un solo núcleo de hielo groenlandes) extrapolable como mucho a una escala regional, pero nunca global,  al que además se asocian ciertos eventos de forma sumamente sesgada y desde una perspectiva occidental, según interese al autor. Varios ejemplos:

- Entorno al año 117 dc, bajo el mando de Trajano, el Imperio Romano alcanza su apogeo en poder y extensión, curiosamente coincidiendo con un acusado enfriamiento según el registro GISP. Sin embargo, en la gráfica se limitan a señalar el muro de Adriano después de un incendio en Roma... vaya, será un despiste.

- Siguiendo con Roma, resulta que entre los años 386-476 dc es cuando el Imperio de Occidente se desmorona hasta consumar su colapso definitivo. Al contrario de lo esperado, coincide justo con un óptimo climático relativo (según GISP) pero, a pesar de su gran relevancia histórica, al autor le parece mejor señalar el pico de la civilización Maya, precisamente la única referencia externa al ámbito occidental-mediterráneo en la gráfica.

- Después del Óptimo Medieval el clima se enfría hasta culminar en la Pequña Edad de Hielo (PEH). Justo antes de la PEH, entre los años 1200 y 1370, cuando el registro indica ya un periodo frío, asistimos al surgimiento del segundo imperio con mayor extensión de la historia, el Mongol. Pero debe ser que para el autor Asia queda demasiado lejos... a no, que también llegó a Europa oriental... un pelín más cerca que los Mayas.

- Por último, y creo que lo más llamativo es que ya en plena PEH, el periodo más frío desde el Óptimo Holocénico hace 8000 años según el registro GISP, es cuando tienen lugar el Renacimiento (s. XV-XVI), la Ilustración (s. XVIII-XIX) y la Revolución industrial (s. XVIII-XX). Nada menos que el periodo en el que, después del oscuro, casposo y dogmático medievo, progresan como nunca antes las artes, la ciencia, los estados, y los movimientos sociales y políticos antecesores de lo sistemas contemporáneos, y cuando se inicia el boom demográfico mundial. 

En conclusión, si tanto valoramos el buen escepticismo científico, ¿por qué no lo aplicamos a simplezas localistas y sesgadas como este tipo de gráficas y al infumable blog del que procede?

Os dejo este enlace:

https://wattsupwiththat.com/2018/08/29/what-is-warming-the-earth/?cn-reloaded=1

La religión es una cuestión de creencias, la ciencia es una cuestión de datos de la realidad.
Por eso mismo, los datos paleoclimáticos nos muestran la realidad de nuestro mundo, que no tiene piedad por las ideologías.

Interglacial Comparisons

Most people don’t realize that the Earth is still in a long term ice age that started about three million years ago and has had many alternating cold glacial periods interspersed with warmer interglacial periods. We are currently in an interglacial period where global temperatures have been near our modern “normal” for about 12,000 years now. In addition to our current interglacial period, there have been four previous interglacial periods in the last 500,000 years. Each one has been spaced about 100,000 years apart and lasted about 2,000 to 25,000 years with temperatures at or above our current modern “normal”. These observations are based on the EPICA Antarctic ice core climate reconstruction using oxygen isotope ratios as a proxie for global temperature change.



 

Creo que este señor algo debe de saber...
https://www.heraldo.es/noticias/suplementos/tercer-milenio/ciencia-ciudadana/2018/09/13/luis-pomar-co2-no-causa-calentamiento-global-1266376-2261035.html?utm_source=facebook.com&utm_medium=socialshare&utm_campaign=mobile_web

Creo que este señor algo debe de saber...
https://www.heraldo.es/noticias/suplementos/tercer-milenio/ciencia-ciudadana/2018/09/13/luis-pomar-co2-no-causa-calentamiento-global-1266376-2261035.html?utm_source=facebook.com&utm_medium=socialshare&utm_campaign=mobile_web

Un hombre sensato y con muchos años de experiencia, gracias Nikhotza.
Saludos.