The Bellatrix and Paris upgrades chained execution and consensus clients at block 15537393. ETH issuance dropped sharply and GPUGraphics processing unit — a chip optimized for parallel math; now used for graphics, ML, and scientific computing. miners pivoted elsewhere. Rollups still handled scale, but the base layer shed its largest environmental criticism — a template other chains watched closely.

The Merge was the largest live consensus upgrade in blockchainA distributed ledger where records are chained cryptographically — designed for tamper-resistant shared state. history.

It cut Ethereum's energy use and shifted security economics to stakers.