Well there is certain uncertainty.
This load of links does not fill me with any confidence that its being looked at clearly.
There are three ideas here:
(1) earth magnetic field changes are extraordinary and will change climate
(2) solar changes are extraordinary and will change climate
(3) CO2 changes (known extraordinary) will not change climate
Let's go for it:
(1) This looks a pretty fair summary:
http://phys.org/news/2014-05-earth-magn ... imate.html
If we really have a field reversal over the next 200 years that would be a big deal. I'm inclined not to accept this without more evidence, especially because although the high rate of change of field as now revealed by the satellites is interesting the changes are patchy and non uniform - we don't know what they will add up to.
However we do not the overall effect on temperature is small because this is a change in temperature way above where there is any real atmosphere - 100-500km. It will have no direct effect on temperature of the layers below. It could have an indirect effect of mag field changes alter precipitation etc (there are mechanisms, Lundqvist etc, but currently they don't seem very significant. Jury is still out but its a long shot).
(2) The direct effect of sunspot cycle changes is known and quite small. (If it were big we'd see a strong 11 year signature in the earth climate correlated to sunspot cycles - we don't). Insolation is now measured accurately and the changes with solar activity which are real are not large enough to have much effect, even for an extreme Maunder minimum type change - whether we are currently headed for that or not is unclear. You have to suppose some indirect effect where long-term changes in the sun that affect sunspots also emerge as solar wind changes etc and then affect climate on earth. It is not impossible, but again it is a long shot.
maybe there is some decent (ie substantial decent science) information on this - I have not found anything much.
(3) This is just wrong, taken literally. We know the forcing from CO2 in climate. We known the change in CO2. With neutral feedbacks it is pretty small, though not insignificant. What are feedbacks is the big bone of contention - but they affect all forcing sources equally - the feedback mechanism is temperature and it does not matter what this came from.
If we had no climate models and no paleo studies or volcanic aerosol studies to inform us then would the default position be neutral feedback?
Certainly not, because the basic physics of GHGs in the atmosphere is dominated by H2O and the change in H2O vapour concentration is governed by temperature. Hotter air => more moisture in air. RH stays the same is a pretty good first approximation, though obviously it will not always hold. And we know the equilibration time for water in the air (in equilibrium with ocean water) is about 2 weeks, so this is a fast-acting feedback.
That gives us a definite medium-size positive feedback. Which makes the effect of CO2 larger - though still not alarming large, maybe 1.5C/doubling.
The debate is then whether other feedbacks: vegetation, albedo, clouds, are positive or negative and what magnitude they have. That is complex.
The only way to get lower CO2 sensitivity is to have more negative feedbacks - and that also scales down climate variability from all other causes.