Is Earth's Climate Related to Solar Cycles?

There seems to be a relationship, certainly. Just looking at the graph above appears to suggest at least a superficial relationship.

It is clear that the late 20th Century warming spell matched the duration of the two shortest, fastest solar cycles in the historical record ( 21 and 22) At the same time thare was a matching sequence of strong El Nino events. These points should not be lightly dismissed. The cooling fears of the 60's and early 70's coincided with weak cycle 20 and the cessation of warming occurred during cycle 23 which has been weaker than the two cycles before it.

On balance the evidence shows that solar is more likely the cause than CO2 but the issue can soon be resolved by observing the global temperature changes that occur as a result of the extended cycle 23 and the probable weak cycle 24.

If we now get a period of natural cooling it might well last several decades.There has been a gradual background and wholly natural warming trend since the end of the Little Ice Age. Of course it is all a matter of trends over time periods. You can 'prove' any trend you require by choosing the right time scale. What matters is the scale of human influences either towards cooling or towards warming as against the underlying trend behind natural variability. It really is an unknown quantity. Even the scale and trend behind natural variability is subject to an unknown number of overlapping cycles from multiple causes many of which are unknown, unquantified or both. _Source__via_GreenWatch

We are overdue to enter Solar Cycle 24. Solar Cycle 24 is a solar cycle that was supposed to have been one of the strongest cycles in the past 400 years, according to NASA solar prognosticators. We have an opportunity to determine whether the correlation between the length of the solar cycle, and Earth's estimated average temperature, will hold during the next two solar cycles: cycle 24 and cycle 25--a cycle predicted to be exceptionally long and weak.

There is a lot more to solar variation than just sunspot number. The possible mechanisms by which solar variation can affect the climate of Earth are much more numerous than the gnomes of NASA Goddard are willing to admit. The cosmic ray hypothesis of Svensmark is only one of many potential means by which the Solar dynamo can impact Earth's naturally chaotic climate.

Sir Karl Popper attempted to head off an ongoing takeover of science by ideological interests, but in the field of climatology, many of Popper's lessons have gone unlearned.

Popper, then, repudiates induction, and rejects the view that it is the characteristic method of scientific investigation and inference, and substitutes falsifiability in its place. It is easy, he argues, to obtain evidence in favour of virtually any theory, and he consequently holds that such ‘corroboration’, as he terms it, should count scientifically only if it is the positive result of a genuinely ‘risky’ prediction, which might conceivably have been false. For Popper, a theory is scientific only if it is refutable by a conceivable event. Every genuine test of a scientific theory, then, is logically an attempt to refute or to falsify it, and one genuine counter-instance falsifies the whole theory. In a critical sense, Popper's theory of demarcation is based upon his perception of the logical asymmetry which holds between verification and falsification: it is logically impossible to conclusively verify a universal proposition by reference to experience (as Hume saw clearly), but a single counter-instance conclusively falsifies the corresponding universal law. In a word, an exception, far from ‘proving’ a rule, conclusively refutes it. __SEP

Climatology--as interpreted by the bureaucrats at the UN's IPCC, and by politician Al Gore--has become an unfalsifiable ideology, rather than a science. It has become a secular religion, like Marxism or other leftist ideology of "social justice". It has become an instrument of social justice, rather than a branch of science. Sadly, Gavin Schmidt of NASA Goddard has acknowledged the unfalsifiability of CAGW, catastrophic anthropogenic global warming.

Climatology is not the only former branch of science to be attempting the "ideological breakaway." But it is certainly the best financed and most politically connected.

A lot is at stake, as the violent inner workings of our local star go about their cyclical activities. We should assume an attitude of humble observation, curious and open to what we may find.