The abstract:
Although the processes of climate change are not completely understood, an important causal candidate is variation in total solar output. Reported cycles in various climate-proxy data show a tendency to emulate a fundamental harmonic sequence of a basic solar-cycle length (11 years) multiplied by 2N (where N equals a positive or negative integer). A simple additive model for total solar-output variations was developed by superimposing a progression of fundamental harmonic cycles with slightly increasing amplitudes. The timeline of the model was calibrated to the Pleistocene/Holocene boundary at 9,000 years before present. The calibrated model was compared with geophysical, archaeological, and historical evidence of warm or cold climates during the Holocene. The evidence of periods of several centuries of cooler climates worldwide called “little ice ages,” similar to the period anno Domini (A.D.) 1280–1860 and reoccurring approximately every 1,300 years, corresponds well with fluctuations in modeled solar output. A more detailed examination of the climate sensitive history of the last 1,000 years further supports the model. Extrapolation of the model into the future suggests a gradual cooling during the next few centuries with intermittent minor warmups and a return to near little-ice-age conditions within the next 500 years. This cool period then may be followed approximately 1,500 years from now by a return to altithermal conditions similar to the previous Holocene Maximum. source
They note that the warming seen this century doesn't match that which occurred in the Medieval Optimum. In other words, it was warmer a thousand years ago than it is now.
"However, geophysical, archaeological, and historical evidence is consistent with
warming and cooling periods during the Holocene as indicated by the solar-output model. The current warm period is thought to have not reached the level of warmth of the previous warm period (A.D. 800-1200), when the Vikings raised wheat and livestock in Greenland. Therefore, the magnitude of the modern temperature increase being caused solely by an increase in CO2 concentrations appears questionable. The contribution of solar output variations to climate change may be significant.” Charles A. Perry and Kenneth J. Hsu, “Geophysical, archaeological, and historical evidence support a solar-output model for climate change, PNAS, 97(2001):23, p. 12436
An interesting comparison of their model with the C14 production, which is related to the strength of the sun's output, shows that their model fits the known variations.
Their comment that the observed warming can't be due to CO2 alone is spot on. CO2 hysteriacs rarely seem to look at the source of all our heat--the sun.
Glenn
ReplyDeleteWhat warming? I thought that you maintained that the temperature record is and was not good enough to detect much warming.
Dave W
Hi Dave,
ReplyDeleteWe know that the world is warmer than it was in the Little Ice Age. That warming, that has occurred over 250-300 years is still warming.
So, why do I think that the present record is worthless for determining the amount of global warming? Because of the urbanization and heat sources next to MODERN thermometers. If you think back, air conditioners (at least in the US) didn't become really widespread until the late 1950s to early 1960s. It is the heating of thermometers after this time that make the record useless. Prior to that, when energy use in a city was less than today, the thermometers were not so biased.
It was not clear that you were talking about warming since the last ice age. Now I understand.
ReplyDeleteDave Wallace
Sorry for the lack of clarity.
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ReplyDeleteTo have solar output explaining that level of temperature change would imply high climate sensitivity and lend credence to the idea that doubling co2 will lead to multiple degrees Celsius of warming. Furthermore if solar output is in good correlation with temperature in the past, it makes the recent divergence of solar output trend and temperature trend all the more glaring, implying a shift away from the previously dominant cause of climate change in the past 50 years...any ideas what the new dominant cause might be?
ReplyDeleteHi Blob. CO2 lags temperature; it doesn't LEAD temperature. The oceans contain about 30-50X more CO2 than the atmosphere does. If you warm the oceans, they degas CO2 which then causes the atmospheric content to rise. You can see that this is what is happening by reading this post http://themigrantmind.blogspot.com/2009/03/do-climatologists-beleive-in-backwards.html
ReplyDeleteIf the sun's output goes down, so will the temperature. I am sure that you saw today that the arctic ocean ice is just about back to normal.
http://nsidc.org/data/seaice_index/images/daily_images/N_stddev_timeseries.png
That means that the earth is cooling down, not warming up as the attrociously-sited thermometer record claims.
I am about to post a post on the fact that the snow cover each winter is going up all the while the climatologists keep telling us that the earth is getting warmer. That seems highly unlikely that a warmer world would result in a bigger coverage of snow each winter.
Thus, to finally answer your question, I don't think there is a divergence. I don't believe thermometers next to heat sources can tell us the true temperature. Thus the divergence is due to urban heat, not reality.