This article, referencing this paper, describes the main concern that motivated me to start this blog. From the article:

but what’s destroying species today is habitat fragmentation and loss, overhunting and over-exploitation, agricultural expansion, pollution, and industrial development

Christopher Ketcham, Addressing Climate Change Will Not Save The From Planet

It is not just an emissions problem but also a consumption problem. 

In my favorite video on Youtube, Brian Cox and Joe Hanson describe what it means to be alive. (I am sure I referenced this before.) You have a reservoir of order – the sun. The cascade of energy coming down to earth allows for the circle of life to evolve. Life on earth does not create nor destroy energy. It just increases the entropy in the system. We consume other living things as energy sources. (The sun raises them again directly with photosynthesis.) Our livestock consumes sources of energy. Our machines also consume sources of energy. 

With 8 billion people, we consume more resources than the earth has. It is not sustainable. That is the reason for an increased rate of extinction on earth.

Being alive, we have emissions. Our livestock has emissions. Our machines also have emissions. These exasperate the problems of our consumption.