There's an overemphasis on conservation and other idyllic energy sources that can be harmful in that it hampers new technology and innovation.
If we want to stabilize the carbon dioxide in the atmosphere at some level - it really doesn't matter which level - you end up having to stop emissions virtually completely.
Injecting CO2 into an underground reservoir would certainly change the local environment and thus affect the organisms that live there. Some will thrive, and others will suffer. While we should minimize such impacts, they cannot be avoided completely. The same happens when one plows a field, builds a house or a road, or waters a lawn.
The fact that companies are getting into building power plants that collect their own CO2 on-site shows there's some leadership in that industry. Some industries have seen the writing on the wall: that carbon will have to be managed.
My personal view is the true long-term storage is mineral carbonates, which is some form of accelerated weathering.
Fossil fuels will run out not because of limited resources but because of the environmental impact. If I can solve that impact, I have basically increased the resource base by a vast amount.