I'm not sure what that means, as forest/jungle density varies greatly as well as species and their absorption of CO2. Did the paper take into account the rest of the ecosystem changes that could capture even more CO2?

Regardless, this is only one of potentially thousands of ways we can make an impact. We won't solve the problem without cooperation, but we also don't even have to cooperate at all to start. All of us can start right now and the combined effort will lead to results.