CO2 and Climate Change
As Kiwiiano points out this would have significant ramifications for climate. How much higher are CO2 levels going to get because of these additional reserves?
Peak oil/gas/coal is the last ditch hope to prevent catastrophic climate change by forcing us to reduce carbon emissions even if we are unable to do so voluntarily. If humans had access to infinite fossil fuels we'd happily push CO2 levels ever higher and higher, wiping out most life on land and in the oceans in the process. We'd just not see it without hindsight, like the proverbial frog in a slowly heating pan of water.
In many ways it would be good to just pretend this additional gas wasn't there and just act as if we were in such a situation.