Ethereum is switching off its mining in favor of another consensus system called "proof-of-stake." Basically the mining hardware and electricity are replaced by the currency itself. There's a consensus protocol that works if people don't cheat in certain ways, it's provable if someone cheats, and the "miners" lock some ETH into the system as a security bond. If someone submits a proof that you cheated then you lose your bond. Energy consumption will drop by an estimated 99.95%.
Most web3 stuff runs on Ethereum, which is the second-biggest energy consumer in crypto. Bitcoin is the biggest and has no plans to move to proof-of-stake, but isn't really involved in web3.
Ethereum's proof-of-stake protocol has been running in parallel for a year with billions of dollars in real ETH deposited, and for the merged system there's a multi-client testnet running.
We’ve been hearing this tune for several years now. Ethereum was originally planned to move to PoS in January 2020. That date was blown and many dates projected since have also been missed. Repeating this “the end is near!” argument in response to very valid concerns about the environmental impact is getting a bit old.
Yes, I expect to see these "dates have been missed before" comments up to the day it hits production.
There's a big difference between "we have a design worked out and think it will take this long" and "we've been running the new system in production for a year, merging it with the old system is relatively easy, and we've got all the clients running the merge together on a public test network." Historically, anything they've gotten to the point of a multi-client testnet has taken well under a year to go live.
It's been delayed before, but hopefully it happens this time. I don't own any, but it would be nice for GPU prices to normalize and the environmental cost would go down substantially.