Ethereum validator and node growth leads to emissions decline: Report

The Ethereum network’s greenhouse gas emissions have dropped by an estimated 99.97% since its shift to proof-of-stake, despite a big rise in node count.

That’s according to new research by the Cambridge Centre for Alternative Finance. The organization has upped its crypto research effort after in April launching the Cambridge Blockchain Network Sustainability Index (CBNSI) — a measure that detailed Ethereum’s electricity consumption pre- and post-Merge.

The Ethereum network currently is responsible for 2.8 kilotonnes of carbon dioxide equivalent (KtCO₂e) on an annualized basis, the CCAF said in a Friday report.

“To contextualize, this would equate to the emissions from five round-trip airplane flights from London to New York, the annual energy consumption-related emissions of 450 UK households, or the annual carbon sequestration capacity of 270 acres of forest,” the report states.

Ethereum switched to a proof-of-stake consensus model in September 2022. The Ethereum Foundation had estimated the Merge would reduce the blockchain’s power consumption by 99.95%.

Read more: Ethereum switches to proof-of-stake after 7 years of work

But electricity usage is only one piece of an environmental impact assessment, according to the Friday report.

Additional data was required to convert electricity consumption to greenhouse gas emissions. The CCAF used off-chain data from the peer-to-peer communication of Ethereum nodes to gather both electricity usage and the geolocational distribution of nodes.

The number of Ethereum validators has grown 57% since April 1, reaching 880,822. Ethereum nodes have grown to 14,072, reflecting a 23.2% increase over that span.

The network’s annual electricity consumption increased by 21.2% in those eight months, from 6.19 GWh to 7.50 GWh — roughly the annual electricity use of 2,000 English households, the Cambridge data shows.

As for where the nodes are, Europe and North America are home to 43.3% and 40.5% of them, respectively, following the Merge.

The CCAF estimates pre-Merge greenhouse gas emissions were about 10.3 MCO₂e. The latest post-Merge figure of 2.8 KtCO₂e reflects a 99.97% drop despite a substantial increase in the number of Ethereum nodes, the report notes.

The network is now powered by nearly 48% sustainable energy — including 32% renewables and 16% nuclear — the CCAF estimates, with the remaining 52% coming from natural gas, coal-fired power, and oil.

The CCAF said it next looks to enhance its Cambridge Bitcoin Electricity Consumption Index (CBECI). Despite Ethereum’s shift to proof-of-stake, bitcoin’s proof-of-work consensus model is a cornerstone of its identity, the report acknowledges — making a similar transition “not as straightforward as it might appear at first glance.”

The research institute adds: “The narrative of Ethereum and Bitcoin’s different paths is not just a tale of technological advancements but also reflects different ideologies and priorities of their communities, highlighting the multifaceted complexity inherent in the evolution of leading blockchain networks.”