El cambio climático y sus causas. Scafetta.

Este artículo discute los límites de la Teoría del Calentamiento Global Antropogénico apoyado por el IPCC. Se propone una teoría fenomenológica del cambio climático basada en las propiedades físicas de los datos mismos. Al menos el 60% del calentamiento observado desde 1970 parece estar inducido por ciclos naturales que están presentes en el sistema solar. Se predice una estabilización climática -o un enfriamiento por el modelo fenomenológico, hasta 2030 - 2040.

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Mi resumen:

Lo más interesante, tal vez, el tratamiento de los conocidos ciclos climáticos de sesenta y pico años -tan estudiados por la FAO en ralación con los ciclos de la pesca mundial. Con el consiguiente argumento de que los modelos climáticos no los predicen, y por tanto exageran la posible atribución del calentamiento al CO2. Y si esta está exagerada en la medida de esos ciclos -de al menos 0,3ºC, el “problema” del calentamiento global para 2.100 en vez de estar en el rango de 2ºC - 6ºC (IPCC), estaría en el rango de 1ºC - 1,5ºC. O sea, el perfecto no problema.

Parece que la atribución de esos ciclos a los cambios en la irradiación solar es muy problemática, y en general los físicos solares se comen a Scafetta con papas cada vez que lo menciona. Pero el mismo Nicola plantea otras posibilidades astronómicas, no directamente solares. Y en cualquier caso, esos ciclos están ahí, y rebajan mucho la teoría alarmista. Tanto como para mandar a paseo a los alarmistas, mientras no presenten algo con cierto fuste.

Muy recomandable, y con muy interesantes gráficos y citas.

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PDF:

• Climate Change Cause (Scafetta)

• http://yosemite.epa.gov/ee/epa/eed.nsf/vwps/360796B06E48EA0485257601005982A1#video

• Dr. Nicola Scafetta summarizes “why the anthropogenic theory proposed by the IPCC should be questioned”

Añadido / actualización:

Judith Curry está diciendo básicamente lo mismo, aunque con diferente peso, en esta entrevista [–> ];

P: You’ve talked about potential distortions of temperature measurements from natural temperature cycles in the Atlantic and Pacific oceans, and from changes in the way land is used. How does that work?

R: Land use changes the temperature quite a bit in complex ways—everything from cutting down forests or changing agriculture to building up cities and creating air pollution. All of these have big impacts on regional surface temperature, which isn’t always accounted for adequately, in my opinion. The other issue is these big ocean oscillations, like the Atlantic Multidecadal Oscillation and the Pacific Decadal Oscillation, and particularly, how these influenced temperatures in the latter half of the 20th century. I think there was a big bump at the end of the 20th century, especially starting in the mid-1990s. We got a big bump from going into the warm phase of the Atlantic Multidecadal Oscillation. The Pacific Decadal Oscillation was warm until about 2002. Now we’re in the cool phase. This is probably why we’ve seen a leveling-off [of global average temperatures] in the past five or so years. My point is that at the end of the 1980s and in the ’90s, both of the ocean oscillations were chiming in together to give some extra warmth.

If you go back to the 1930s and ’40s, you see a similar bump in the temperature records. That was the bump that some of those climate scientists were trying to get rid of [in the temperature data], but it was a real bump, and I think it was associated with these ocean oscillations. That was another period when you had the Pacific Decadal Oscillation and the Atlantic Multidecadal Oscillation chiming in together. These oscillations and how they influence global temperature haven’t received enough attention, and it’s an important part of how we interpret 20th-century climate records. Rather than trying to airbrush this bump in the 1940s and trying to get rid of the medieval warm period—which these hacked e-mails illustrate—we need to understand them.

They don’t disprove anthropogenic global warming, but we can’t airbrush them away. We need to incorporate them into the overall story. We had two bumps—in the ’90s and also in the ’30s and ’40s—that may have had the same cause. So we may have exaggerated the trend in the later half of the 20th century by not adequately interpreting these bumps from the ocean oscillations. I don’t have all the answers. I’m just saying that’s what it looks like.