The Ethereum blockchain is home to the second most valuable cryptocurrency, the Ether (ETH), as well as many other cryptos and, more recently, NFTs. It's also been a source of (well-deserved) criticism because of its high energy usage, but that should change soon.

Related: What is Ethereum, and What Are Smart Contracts?

"The Merge" is happening today (September 14), and it will transition Ethereum's consensus mechanism from its current proof-of-work scheme to proof-of-stake. It's not happening at a specific time, but rather, it's scheduled to happen whenever the blockchain reaches a specific Terminal Total Difficulty (TTD) number. That's a value that represents the cumulative difficulty of all Ethereum blocks ever mined, and it's set at 58750000 P. That value should be reached either tonight or very early tomorrow. You can see an exact countdown, based on network conditions, here.

The transition to proof-of-stake means the network will move away from using computationally-intensive mining to verify transactions, and it will shift to using validators staking their own cryptocurrency to verify transactions instead. In other words, Ethereum mining is dead. Proof-of-stake is already used by blockchains such as Cardano, Solana, and Polygon.

The fact that Ethereum won't use mining anymore is good for several reasons. For one, it's better for the environment. Cryptocurrency mining worldwide consumes an absurd amount of electricity. Ethereum alone consumes roughly as much power as the entire nation of Chile, and it has a carbon footprint comparable to Hong Kong's. Mining also creates e-waste, as GPUs used for mining have a much shorter lifespan than gaming GPUs. The Merge would solve both of those issues, bringing the blockchain's power consumption down by around 99%, while also ensuring miners don't hoard GPUs that would otherwise be used for other purposes (like AI art). Not relying on mining also means that Ethereum fees (also known as gas fees) will be reduced considerably, something that has become more of a problem in recent years.

Related: Proof of Work vs. Proof of Stake: What's the Difference?

There will be forks of Ethereum that will continue the blockchain's proof-of-work scheme, with at least one fork coming "within 24 hours" of the transition. These will be made mostly as an attempt by miners to not lose their current source of income.  Some of the biggest ETH mining pools, like Ethermine, have confirmed that they wouldn't support any fork. And unless most miners throw their weight behind a single fork, the chances of a PoW fork being profitable in any way are zero to none.

Following the change, Bitcoin will be the only remaining major crypto sticking with proof-of-work. Bitcoin mostly uses ASICs, or application-specific integrated circuits, for mining rather than GPUs. At the very least, this is good news for the environment, and even better news for the GPU market, as new graphics cards from Nvidia, AMD, and Intel are nearing.

Source: Ethereum