That actually depends on how large the ejection, spike , or flare is. If you live or even have visited the north or south poles, you can see the effects of solar activity in the night sky. The most drastic that we see, or more accurately hear, is when a flare causes solar winds that disrupt communications satellites. The Earth's atmosphere protects us pretty well from most of the effects of Sol. In order for Earth to be drastically effected by the sun's actions, it would have to shed a huge portion of its corona on a near nova level. And being a yellow star, the odds of the Sol doing anything remotely close to that are near Nil.