INTRODUCTION.

Blockchain technology is a distributed ledger technology that records and verifies transactions and data on a peer-to-peer network. Blockchain technology has various applications and benefits, such as enhancing security, transparency, and efficiency of digital transactions and data. However, blockchain technology also has a significant environmental impact, as it consumes a lot of energy and resources, and generates a lot of greenhouse gas emissions.

The environmental impact of blockchain technology depends on several factors, such as:

- The type of blockchain platform and protocol, which determines the design, functionality, and performance of the system. For example, public blockchains, such as Bitcoin or Ethereum, are open and accessible to anyone, but they require a lot of computational power and consensus mechanisms to maintain the security and integrity of the network. Private blockchains, such as Hyperledger or Corda, are closed and restricted to authorized participants, but they offer more scalability and efficiency of the system.

- The type of consensus mechanism, which determines the rules and processes for validating and adding transactions and data to the blockchain. For example, proof-of-work, which is used by Bitcoin and Ethereum, requires participants to compete and solve complex mathematical problems, which consumes a lot of electricity and generates a lot of heat. Proof-of-stake, which is used by Cardano and Polkadot, requires participants to stake a certain amount of tokens, which reduces the energy consumption and emissions of the system.

- The type of application and use case, which determines the purpose, scope, and frequency of the transactions and data on the blockchain. For example, cryptocurrency transactions, such as Bitcoin or Ether, involve the transfer of value and require a high level of security and verification, which increases the energy consumption and emissions of the system. Supply chain transactions, such as VeChain or IBM Food Trust, involve the tracking and tracing of products and materials, which improves the transparency and efficiency of the system.

According to a study by the University of Cambridge¹, the annual electricity consumption of Bitcoin, the largest and most popular blockchain platform, was estimated to be 129.09 terawatt-hours (TWh) as of September 2022, which is more than the annual electricity consumption of countries such as Argentina, Sweden, or the Netherlands. The carbon footprint of Bitcoin was estimated to be 61.76 million tonnes of carbon dioxide equivalent (MtCO2e) as of September 2022, which is more than the annual carbon footprint of countries such as Switzerland, Denmark, or Norway.

The environmental impact of blockchain technology is not only a challenge, but also an opportunity for innovation and improvement. The blockchain community and industry are actively exploring and developing solutions and alternatives to reduce the energy consumption and emissions of blockchain technology, such as:

- Using more energy-efficient and sustainable blockchains and consensus mechanisms, such as proof-of-stake, proof-of-authority, or proof-of-burn, which can lower the computational and environmental costs of the system.

- Using renewable and clean energy sources, such as solar, wind, or hydro, to power the blockchain operations and infrastructure, which can reduce the carbon footprint and emissions of the system.

- Using blockchain technology to support environmental protection and sustainability, such as carbon trading, renewable energy certificates, or environmental monitoring, which can create positive environmental impacts and value.

Blockchain technology is a novel and transformative technology that has the potential to revolutionize the digital economy and society. However, blockchain technology also has a significant environmental impact that needs to be addressed and mitigated. Therefore, blockchain technology requires careful and responsible development, adoption, and regulation, as well as continuous research and education.

(1) Blockchain and the environment — European Environment Agency. https://www.eea.europa.eu/publications/blockchain-and-the-environment.

(2) Blockchain’s environmental impact: PwC. https://www.pwc.com/us/en/services/digital-assets/blockchain-environmental-impact.html.

(3) The Environmental Impact of Blockchain Technology | Nasdaq. https://www.nasdaq.com/articles/the-environmental-impact-of-blockchain-technology.

(4) The Environmental Impact of Blockchain: Examining Sustainability in .... https://techbullion.com/the-environmental-impact-of-blockchain-examining-sustainability-in-distributed-ledger-technology/.

(5) What Are The Environmental Effects Of Blockchain Technology?. https://emagazine.com/environmental-effects-of-blockchain/.