Fusion would be a big help for sure, but not strictly necessary. Consider that total sunlight reaching the Earth’s surface is ~120PW, or 15MW for each of 8 billion people. That’s about 1000x current primary energy use. Commercially cost-effective solar cells are currently ~20% efficient. If you could get install and balance of system costs down enough, with universal adoption rooftops alone could theoretically get you within spitting distance of an all-solar grid (yes in practice it won’t happen this way, it will take massive amounts of complementary infrastructure and other energy sources and other technologies, etc., I’m just talking about land usage requirements.)
And yes mining gets more difficult in absolute terms, but I think you’re (on a timescale of decades) underestimating the value of improving mining and metallurgical technology while overestimating the difficulty of recycling. On a timescale of longer than decades, “improving technology” expands to include things like automated asteroid mining (and manufacturing?) using space-based solar power.
Fusion would be a big help for sure, but not strictly necessary. Consider that total sunlight reaching the Earth’s surface is ~120PW, or 15MW for each of 8 billion people. That’s about 1000x current primary energy use. Commercially cost-effective solar cells are currently ~20% efficient. If you could get install and balance of system costs down enough, with universal adoption rooftops alone could theoretically get you within spitting distance of an all-solar grid (yes in practice it won’t happen this way, it will take massive amounts of complementary infrastructure and other energy sources and other technologies, etc., I’m just talking about land usage requirements.)
And yes mining gets more difficult in absolute terms, but I think you’re (on a timescale of decades) underestimating the value of improving mining and metallurgical technology while overestimating the difficulty of recycling. On a timescale of longer than decades, “improving technology” expands to include things like automated asteroid mining (and manufacturing?) using space-based solar power.