We are seeing now that bright light in the sky means a change in time. Remembering back to the end of season 2, such an event occurred (or something similar) as a consequence of Desmond going under the dome and turning the emergency key.

What I wonder is, did this bring about a change in time too? If so, forward, or backwards?

Is it an individual case of it turning Desmond into the "special" person Faraday informs him of when they meet at the Swan hatch "back door"?