Reddit reviews Avatar: A Confidential Report on the Biological and Social History of Pandora

Basically what other people said, though I'm gonna expand on it a little more.

Earth in Avatar is facing multiple problems. There's the overpopulation leading to not enough food of course. Then there's the overpolution making gasmasks outside mandatory. Finally there's an energetic crisis caused by the Earth building super fast trains that connect the whole world together... at the expense of consuming huge amounts of energy. That, plus of course the daily energy expenses of greenhouses for food, water filtration and so on.

Also there was another world war somewhere during the time before the movie starts off (the protagonist of the movie is that war's veteran, hence why he's on a wheelchair).

So yeah, Unobtaniun doesn't help with feeding people, however as a superconductor (meaning it has the same capabilities at a room temperature normal conductors can only achieve cooled down, consuming more resources and energy) it can solve one of the problems.

Also, there was a book released about the nature of Pandora as well as about the equipment humans use. It includes details about the flora of Pandora that may be secondary reasons for Humans to be there (I haven't read it in a while, but apparently aside from obviously using the plants of Pandora to sustain the human population, there are some plants with abilities that could help Earth recover, such as a plant literally consuming pollution from water, which could possibly make oceans habitable again on Earth).

Unobtanium is the macguffin of the film because it's an anti-corporation movie and of course corporation only cares about shiny rocks that need to be extracted by any means necessary, but additional reading material suggests there was more to Pandora than just the metal.

I think I might be the first person to mention this, but I'm unsure.

The movie was really great in all of its special effect and rollercoaster-predictable story-line, but there is a point that seems to be shrouded to everyone, either because they refuse to recognize it or because it's too true to say anything about it. The movie may have been considered by some to be a "kid's film" but I'd argue otherwise. Yes, there are elements to it that are childish, but overall I think that it was intended for older audiences. The movie has amazing CGI, good acting, blah blah, yadda yadda, not to mention the fact that Sam Worthington's Aussie accent kept slipping out.
The depth that they gave to Pandora in its biodiversity (if you get a chance, grab a copy of Avatar: The Field Guide to Pandora) was incredible. They went so far into the Sci-fi detail that the avatars were only slightly un-Na'vi. The Avatar have 5 toes, smaller eyes, and more human noses. The differentiation was incredible even down to those detail. The language, as well, had obvious work put into it.

To me, I saw this movie as an amazing commentary on what we are doing to our planet. The end (which I will "spoil" because this is, supposedly, a thread for those that have seen it) in which Jake says: "The aliens went back to their dying planet.", as well as when he speaks to the Tree of Souls ("Look into Grace's memory [...] There is no green [on Earth.]") are supposed to be translations to the audience that we are not doing good to our world. This film (however obviously science-fiction as it is, is hearkening to what our eventual outcome could be if we further treat our world the way we do. I remember watching the first scene on Pandora thinking "Wow, they did such a great job making the Human technology look ugly compared to everything on Pandora." We are ugly as a species right now in what we are doing to the planet, and I think that Avatar was an attempt to get people to understand that.

Though apparently few people are getting the message.