Would choosing climate change as an essay topic be too broad of a global issue? I think in lieu of recent global events (hurricanes, floods, droughts, UN climate change discussions, etc) it is a very timely and current issue, but would it be appropriate for the SFS essay?
There are no incorrect topics to write about. If you’re interested in it and can discuss it intelligently, I see no reason why you shouldn’t write about it, especially given the recent events around COP21.