I don't have a good reason but I wouldn't discount the possibility. As life reacts to the higher carbon dioxide levels we will enter into uncharted territory.

I don't have a good reason but I wouldn't discount the possibility. As life reacts to the higher carbon dioxide levels we will enter into uncharted territory. The biggest possible source would be human climate engineering. That would be a huge feat to pull off but if we desperate enough who knows what we could do in 500 years.