The thing about human versus natural activity is what gets me. If there were 200 Mount Pinatubo eruptions in the coming year and the Philippines, Japan and much of Eastern China fell off into the sea - that would be "okay" because it's "natural."
1 Corinthians 15:47 (a). "Man" (and the goils!) is a natural part of this planet. What human beings do, is by definition "natural" - unless you're Benny Hinn and can float around in the air.
But the rest of us are a part of this planet and a vital part of the web of life here. It's wrong to say that human activity is some how inherently "evil" the way the environmental wackos do.
Besides, all of that carbon used to be up here and was a part of living organisms. Plants "breathe" CO2. In earlier ages of the earth the CO2 levels were a lot higher than today and there were no frozen ice caps.
There's a "forest" of frozen trees in Greenland of a species that was thought to be extinct - until they were found growing in isolated parts of tropical China. And the wood still burns though it's a million years old. And being "just" a million years old, it's not like plate tectonics carried Greenland from the tropics to the far north is such a short period of time, geologically speaking.
Was it "bad" when these forests on Greenland were alive and vibrant? Would it be "bad" if they were to return? IMHO, no! It wouldn't be "bad" - but it would be different. I think the term for this difference is "climate change" and it's been going on long before humans ever started to sully up the place.