We’re talking about Bitcoin here because the news is about Bitcoin, it doesn’t mean we don’t care about reducing emissions in other areas. There are articles on HN regularly about EVs, synthetic meat, etc.

One thing that sets POW apart, though, is how it is designed to resist efficiency improvements through the difficulty adjustment mechanism. When hashrate per watt goes up with efficiency improvements, the network difficulty goes up to compensate, so more efficient hardware does not improve the efficiency of the system.