I would say the subject is climate change.
Within the Deep South and North Poles
deep does not need to be capitalized
The reason for this is because of climate change; it causes increase/decreasing of temperature within the atmosphere, specifically effecting animal, humans, and nature.
Eliminate "because of." Instead of using a ;, make two sentences. Change "effecting" to "affecting."
That's where the polar caps comes in; climate change primarily is melting and making it disappear at alarming rate
at
an alarming rate
causing havoc changes to our environment globally.
causing havoc
andThe reason this topic was chosen was because few societies believe they should do something about it since the polar caps are important on earth.
This sentence doesn't make sense. If the polar caps are important, then why do few societies believe they should do something about it?
Though some don't believe we should care about this since they assume it's all a hoax; despite the information, there are facts that go with this.
This sentence would be better off starting at "some"
We as a nation and others
I'm not 100% sure, but I think it needs to be "We, as a nation, and others"