How does the Ethereum Merge help the real and virtual world save energy?

Ethereum completed its "Merge" on 15 September 2022, switching from proof-of-work to proof-of-stake, which the article says sharply cuts the network's energy use. Tests on the Beacon Chain before the Merge suggested a 99.95% reduction, and the carbon footprint of a single Ethereum transaction fell from 109.71 kg of CO2 to 0.01 kg as recorded on 20 September 2022. The article also describes EY's recruiting event on Decentraland, which ran on Polygon and emitted as little as 21 kg of CO2 in May 2022, and notes that the Merge does not directly reduce gas fees.