Writing Feedback / Climate change - Help on finding the subject and any sentence errors [3]

My problem is I type out every thing like a regular paragraph, but i can't figure out what is the subject within it. It would be nice if someone can help me find it or give me a new one that i can incorparate in it.

Within the Deep South and North Poles, glaciers have been melting since around 6.3 million years ago. The reason for this is because of climate change; it causes increase/decreasing of temperature within the atmosphere, specifically effecting animal, humans, and nature. That's where the polar caps comes in; climate change primarily is melting and making it disappear at alarming rate, causing havoc changes to our environment globally. The reason this topic was chosen was because few societies believe they should do something about it since the polar caps are important on earth. 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. We as a nation and others must join together more than ever to comprehend how global warming works and somehow slow or even stop this predicament.