The present state of research on that issue is that we would see a lot more methane coming out of the permafrost, which is a very powerful greenhouse gas, about thirty times as powerful as CO2, molecule for molecule. That would be what we call a positive feedback and would increase warming. For CO2, or carbon emissions, other than in methane, it looks like it would be a wash; it would not be a big change.
The other worrisome thing is that there is a lot of mercury in those permafrost areas, and as the permafrost melts, that mercury is going to come out into the Arctic Ocean and into the northern rivers and have a very serious additional impact on the native people who live in those areas.