"Also the lead writer had refuted the theory that everyone was dead, in purgatory, in heaven or in hell. Yet, at the end they're clearly in some sort of afterlife. "
This is where you are mistaken. The "afterlife" or purgatory was the sideways world. The characters only went there after they died - however purgatory is "timeless" I thought Christian explained this bit pretty well to Jack. This is the secret the characters realized when they touched one another - they were dead and in purgatory. Once they were done with purgatory they were ready to leave - like Locke when I forgave himself and allowed himself to be fixed. Earlier when Desmond and Hurley bribe Ana Lucia Hurley asks why they don't take Ana - Desmond responds that she isn't ready yet. She still has to beat whatever is holding her back in purgatory. Ben makes a conscious decision to stay.
I hope that clears up some of your issues with the purgatory thing - I do agree there were way too many unanswered questions (who got shot in the boat during the flashing sequences, Walt's significance, etc.).
The problem right now at least for plant and animal life is the rate of climate change is drastically more rapid than ever before. This is why we need to work on more carbon neutral solutions to produce energy.
"No, they changed "global warming" to "climate change" because idiots like you thought "global warming" meant that every single point on the planet would monotonically increase year-over-year, and to a lesser extent because "climate change" is more accurate anyway because the increase in carbon dioxide has other effects too, such as ocean acidification. Unfortunately, they failed to consider that idiots like you would think this is more evidence of a massive global conspiracy to steal your freedom and monies."
This guy was being sarcastic? Because he is absolutely correct.