Is the effect of Earths position relative to sun large or small compared to CO2 level in climate change?
The changes Camilo Rada discusses repeat annually so they average out over longer timescales and have no effect on climate. The flares reach less than $1\%$ of the distance to earth and they are a recurring effect so they also average out.

Greenhouse gases have a cumulative effect.

Solar activity is included in the IPCC.