Well the general Sci-Fi solution is some form of galactic expansion, sometimes preceded by a massive die off before people get the point that their planet has exceeded maximum capacity.
As per our current science, we're forever limited to our galactic local group. Exponential growth tends to consume even very big things surprisingly quickly.
I also question whether a mass die off event on this planet won't lock us out from ever rebuilding a spacefaring civilization. We've already used up all the readily accessible fossil fuel that was necessary for us to get this far.
I also question whether a mass die off event on this planet won't lock us out from ever rebuilding a spacefaring civilization. We've already used up all the readily accessible fossil fuel that was necessary for us to get this far.