The phrase ‘greenhouse gas emissions’ or ‘carbon emissions’ doesn’t cary much emotional weight. It sounds like some nerdy, probably unimportant thing.
In reality, our emissions will determine how much the planet warms, which will have a huge effect on humanity. While it’s true that the Earth is better off with some CO2 than it would be with none at all, it is also true that all the additional greenhouse gases being added to the atmosphere now are harmful. As climate scientist Gavin A. Schmidt argues: “If you ask a scientist how much more CO2 do you think we should add to the atmosphere, the answer is going to be none. All the rest is economics.”
Given all of that, I think it makes more sense to use the phrases ‘greenhouse gas pollution’ or ‘carbon pollution’. It accurately reflects the harmful role these emissions play, and it ties them to ideas like the ‘polluter pays principle‘.
Any system which possesses a measure of stability can absorb without catastrophe some increase in the relative quantity of any particular substance. “Pollution”, I think, can be understood as emissions of substances over and above what a system can absorb while maintaining the integrity of that system. So, as I see it, the distinction between “carbon emissions” and “carbon pollution” is purely a question of relative quantity – that is quantity relative to our biosphere’s ability to retain the relevant stability to changes in CO2 concentrations.