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Bard, E. and Frank, M. 2006. Climate change and solar variability: What's new under the sun? Earth and Planetary Science Letters 248: 1-14.
What was done
The authors review what is known, and unknown, about solar variability and its effects on earth's climate, focusing on the past few decades, the past
few centuries, the entire Holocene, and orbital timescales.
What was learned
Of greatest interest to us are Bard and Frank's conclusions about sub-orbital time scales, i.e., the first three of their four major focal points.
Within this context, as they say in the concluding section of their review, "it appears that solar fluctuations were involved in causing widespread
but limited climatic changes, such as the Little Ice Age (AD 1500-1800) that followed the Medieval Warm Period (AD 900-1400)." Or as they say in the
concluding sentence of their abstract, "the weight of evidence suggests that solar changes have contributed to small climate oscillations occurring on
time scales of a few centuries, similar in type to the fluctuations classically described for the last millennium: The so-called Medieval Warm Period
(AD 900-1400) followed on by the Little Ice Age (AD 1500-1800)."
What it means
In the words of Bard and Frank, "Bond et al. (1997, 2001) followed by Hu et al. (2003) proposed that variations of solar activity are responsible for
quasi-periodic climatic and oceanographic fluctuations that follow cycles of about one to two millennia." As a result, as they continue, "the
succession from the Medieval Warm Period to the Little Ice Age would thus represent the last [such] cycle," leading to the conclusion that "our
present climate is in an ascending phase on its way to attaining a new warm optimum," due to some form of solar variability. In addition, they note
that "a recent modeling study suggests that an apparent 1500-year cycle could arise from the superimposed influence of the 90 and 210 year solar
cycles on the climate system, which is characterized by both nonlinear dynamics and long time scale memory effects (Braun et al. 2005)."
Taken together, these several observations leave little need to invoke the historical increase in anthropogenic CO2 emissions as the primary
cause of modern warming. In fact, they leave no such need at all, as solar influences appear to be sufficient to explain the bulk of the
increase in temperature. Nevertheless, much more work is needed to clarify the specific mechanisms by which the solar-induced warming is accomplished.
References
Bond, G., Kromer, B., Beer, J., Muscheler, R., Evans, M.N., Showers, W., Hoffmann, S., Lotti-Bond, R., Hajdas, I. and Bonani, G. 2001. Persistent
solar influence on North Atlantic climate during the Holocene. Science 294: 2130-2136.
Bond, G., Showers, W., Cheseby, M., Lotti, R., Almasi, P., deMenocal, P., Priore, P., Cullen, H., Hajdas, I. and Bonani, G. 1997. A pervasive
millennial-scale cycle in North Atlantic Holocene and Glacial climate. Science 278: 1257-1266.
Braun, H., Christl, M., Rahmstorf, S., Ganopolski, A., Mangini, A., Kubatzki, C., Roth, K. and Kromer, B. 2005. Possible solar origin of the 1470-year
glacial climate cycle demonstrated in a coupled model. Nature 438: 208-211.
Hu, F.S., Kaufman, D., Yoneji, S., Nelson, D., Shemesh, A., Huang, Y., Tian, J., Bond, G., Clegg, B. and Brown, T. 2003. Cyclic variation and solar
forcing of Holocene climate in the Alaskan subarctic. Science 301: 1890-1893
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Reference
Pollack, H.N., Huang, S. and Shen, P.-Y. 1998. Climate change record in subsurface temperatures: A global perspective. Science 282:
279-281.
What was done
A history of global surface temperature over the past five centuries was reconstructed from 358 boreholes spread throughout eastern North America,
central Europe, southern Africa, and Australia.
What was learned
Nearly 80% of the 358 borehole locations experienced a net warming over the past five centuries, while about 20% experienced a net cooling. The mean
temperature increase over the 500-year period for all stations was approximately 1°C.
What it means
This study documents the complexity of earth's climate system, illustrating the fact that not only can the magnitude of temperature change vary widely
across the surface of the planet, but that even its sign may differ from place to place. In the mean, however, the results concur with those of other
recent global climate reconstructions, indicating that global temperatures have risen by about one degree Celsius over the past 500 years. However,
these observations, together with contemporaneous atmospheric CO2 data, tend to argue against CO2-induced global warming.
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Reference
Maasch, K.A., Mayewski, P.A., Rohling, E.J., Stager, J.C., Karlén, W., Meeker, L.D. and Meyerson, E.A. 2005. A 2000-year context for modern climate
change. Geografiska Annaler 87 A: 7-15.
What was done
Many researchers have examined historical proxy temperature changes over the past millennia and beyond in an attempt to quantify the magnitude,
frequency and causes of natural climate variability. However, temperature is not always the best measure of climate, and it is certainly not the only
measure. Few studies, for example, have examined the millennial range and rate of change of hydrologic and atmospheric circulation; yet changes in
these parameters are important because they are involved in more than half of the earth's poleward transfer of heat (Peixoto and Oort, 1992).
In the present study, Maasch et al. attempt to remedy this deficiency by examining changes in eight well-dated high-resolution non-temperature records
over the past two millennia: (1) K+ concentrations from the GISP2 ice core in Greenland, (2) Na+ concentrations from the Siple Dome ice core in
Antarctica, (3) percent Ti from an ocean sediment core in the Cariaco basin, (4) Fe intensity from a marine core near the coast of mid-latitude Chile,
(5) oxygen isotope fractions from Punta Laguna near the Yucatan, (6) carbon isotope data from a speleothem in Makapansgat, South Africa, (7) percent
of shallow water diatoms from Lake Victoria, and (8) lake levels from Lake Naivasha in equatorial Africa. The eight data sets were then compared with
a history of atmospheric 14C, a proxy for solar variability that was obtained from tree rings, to ascertain what, if any, solar influence operated on
these parameters.
What was learned
Comparison of the 14C solar proxy data with the eight climate-related data sets revealed that over the past 2000 years there has been, in the authors'
words, a "strong association between solar variability and globally distributed climate change." This "remarkable coherence" among
the data sets was particularly noticeable in the Medieval Warm Period to Little Ice Age transition, as well as throughout the Little Ice Age.
What it means
Contrary to the strident claims of climate alarmists, the results of this study suggest that the Medieval Warm Period and Little Ice Age were indeed
global phenomena that were likely the products of natural climate variability driven by changes in solar activity. As for the Current Warm
Period, we believe it to be much less due to increases in atmospheric CO2 concentration than to the natural - and likely solar-induced - recovery of
the planet from the coldest period of the current interglacial, i.e., the Little Ice Age.
Reference
Peixoto, J.P. and Oort, A.H. 1992. Physics of Climate. American Institute of Physics, New York.
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Expect things to warm up without the aid of a wood heater in a couple or three weeks. 
get rid of em, now! ya really want it both ways don't ya? Sorry it don't work that way.
It doesn't take a PHD to
realize weather and climate undergo changes.
The climate has been changing long
before humans could have had any impact one way or the other, in fact it changed before we were ever even on earth. 
:moon: