A University of Cambridge study revealed that before a major software upgrade in September 2022, Ethereum's blockchain emitted greenhouse gases equivalent to Honduras's annual emissions. The upgrade, called the "Merge," significantly reduced Ethereum's energy consumption by over 99%. Pre-Merge, Ethereum emitted 27.5 million tonnes of CO2 equivalent since its 2015 launch, comparable to Honduras in 2020. Post-Upgrade, Ethereum's yearly emissions are now around 2.8 kilotonnes, similar to five round-trip flights from London to New York. This transformation challenges the perception of blockchains as environmental polluters. In contrast, Bitcoin, emitting approximately 73.9 MtCO2e annually, is equivalent to Cambodia's 2020 emissions, highlighting differences in blockchain environmental impact. The study emphasizes Ethereum's notable progress in addressing environmental concerns in the crypto sector.