No problem, catastrophists say, there are plenty of other things people may be scared of. Let us welcome global warming. The idea that the global temperature on the planet is gradually growing due to the anthropogenic reasons is not new, but only during the last decades we saw a real upsurge of belief in it, ecological lobbies limiting the activity of industries and so on. And it seems to be working for now, even a recent Climategate scandal involving some of the most prominent statisticians promoting the theory (it showed that they were almost certainly falsifying the data of their research) doesn’t seem to turn the tide of public opinion. The same goes for many other Apocalypse theories, none of which came true in the end.
A formal essay is heavily structured; it includes cited research, has a clear introduction, body and conclusion and supports a stated thesis. This type of essay also employs a formal tone -- it is written in third-person. This is the type of essay you will be expected to write in an academic setting. For example, if you are writing an essay about the theory of evolution, introduce the topic broadly in the introduction, go into detail about the theory based on your research in the body paragraphs and then summarize your findings in the conclusion. Even if the essay you are writing is a persuasive piece -- one in which you try to convince the reader of your stance on an issue -- you still have to back up your arguments with researched facts.