The Intergovernmental Panel on Climate Change (IPCC) perpetuates the deception that they examine all causes of climate change. They only examine human causes, which you can’t identify if you don’t know or understand natural causes.
They tacitly acknowledged the problem by widening the definition in the 2007 Report, but little changed.
Studying human impact excludes anything outside the terrestrial system. They cynically included the Sun in their list of human forcing mechanisms (Figure 1), but then only studied variations in insolation (electromagnetic radiation) thus excluding other solar and astronomic changes.