Conversely, one could say that the theory of anthropogenic CO2 warming is so weak that someone who is an amateur climate scientist (according to Wiki page on him) can debunk it.
If the record shows a strong correlation between the sunspot record and earth temperature (even at a decade-resolution in the past century), and we know that earth’s temperature changes cannot cause changes in the number of sunspots, then it is reasonable to look here when describing climatic changes. IPCC does not appear to show any interest in it. To ignore other theories for global warming is unscientific.