There is an ongoing discussion on the Bitcoin mining and its effect on the climate. [1,2,3,4]. It is evident that proof-of-work scheme has increased the global emissions. This is because Bitcoin has become widely used and the competition on mining new instances to the blockchain is fierce. Further, it is not possible to change this, because Bitcoin is operated with the same working principles as it was launched with in 2008. As these principles cannot be changed, one just waits for every possible Bitcoin to be mined. Therefore, owning Bitcoin can be considered unethical from an ecological perspective.
The proof-of-work scheme, which is used by Bitcoin, has been replaced by proof-of-stake in many new cryptocurrencies. The difference is that proof-of-stake decides the correct blockchain (in case of a, say, fork in the chain) based on the cryptocurrency stake different actors have in the chain. This differs from the proof-of-work, where computing power alone decides the correct blocks and the correct chain. Proof-of-stake mitigates the comparable climate impact of the cryptocurrency in question, when considering cryptocurrency using proof-of-work as their validating principle .
As Bitcoin is not going anywhere, and even proof-of-stake does not render emissions obsolete, one can safely note that there is no end in sight for greenhouse gases generated by FinTech and cryptocurrencies. The old solutions, like Bitcoin, are not going anywhere, and new ones also have issues with scaling up and electricity required.
There is a possibility for blockchains to become part of the solution, however, as opposed to being part of the problem. There is an initiative in EU to create a transparent ledger for climate impact of different market actors . This would effectively make all climate impact recorded into a blockchain, providing free information on the emission levels to smaller companies who have not had access to this type of data. These companies could then provide new services which in turn could mitigate the climate impact in the society.
To conclude, the downsides of using blockchains are worse than the upsides, but this could change in the future. However, it is unclear if this change takes place fast enough considering the heightening pace of the climate crisis.
Blockchain is a tool as any other. It can be used for some problems, while others it cannot solve. We cannot continue, however, without proper definition for a tool. Here a concept of tool neutrality is applicable, which highlights the fact that “technology is not neutral or transparent, but comes with embedded assumptions about operating procedures, often derived from a different context.” . As the common saying goes: “if there is a hammer, everything becomes a nail”.
Does a tool carry with it a prescribed way of use? What is this use for blockchains? The answer dictates if and where blockchains should be employed (see e.g. ). However, this discussion is only beginning  and would provide a rich topic for both academic and layman circles, as the proposed tool, blockchain, is complex. Further, the constantly added features seem to make it even more so.
We can say for certain that blockchain has many attributes, which can make it usable in varied contexts. The technical, economic, social, ecological, and holistic analysis of these contexts is underway, with e.g., different technical propositions for varied use cases. However, the ethical discussion is yet to really begin and therefore, it will take time to arrive to a conclusion, if such is attainable. These debates and technical innovations ultimately dictate where blockchain is used in the future and where its use will be considered ethical.
In this Chapter I would like to highlight two ethical notions: The ethical use of blockchain requires
The blockchain has been seen as a silver bullet for many problems. Smart contracts were observed to quit the need for law-firms in business . The Bitcoin was hailed as new way to do financial transactions, without the need for a central bank . However, in these instances (and others not mentioned), the blockchain technology has changed very little of the old institutions’ working principles. Blockchain has just become another way to do the same things that has been done before. However, this would not mean that ethical use of blockchain is not possible. It is just that it has not been done yet, at least in a larger scale.
: BBC, Bitcoin consumes 'more electricity than Argentina'. https://www.bbc.com/news/technology-56012952
: Digiconomist, Bitcoin Energy Consumption Index. https://digiconomist.net/bitcoin-energy-consumption/
: CNBC, China, Elon Musk raise alarm about bitcoin energy use: Here’s how it could be made more ‘green’. https://www.cnbc.com/2021/06/30/china-musk-raise-alarm-on-bitcoin-energy-use-how-to-make-it-greener.html
: HS, Yhä useampi haluaa rikastua bitcoinilla, ja louhintaan vaadittava sähkö uhkaa jo Kiinan kaltaisten jättien ilmastotavoitteita – Tuhoaako buumi ympäristön? https://www.hs.fi/talous/art-2000007966253.html (in Finnish).
: Medium, Proof of Work vs. Proof of Stake: Which Is Better for the Environment? https://medium.com/oasis-protocol-project/proof-of-work-vs-proof-of-stake-which-is-better-for-the-environment-d6ca69a61411
: EU, Blockchain for climate action. https://digital-strategy.ec.europa.eu/en/policies/blockchain-climate-action
: IGI, Global dictionary: https://www.igi-global.com/dictionary/tool-neutrality/37856.
: Terra, A. C. W. (2021). Blockchain as a tool to improving work condition in the fashion supply chain. PDF: https://www.coppead.ufrj.br/wp-content/uploads/2021/06/AnaClaudiaTerra.pdf
: Ahmed Subeh, I. M. (2020). Blockchain as a technological imaginary: media framing and the views of blockchain professionals in the Arab world. PDF: https://scholarworks.uaeu.ac.ae/cgi/viewcontent.cgi?article=1016&context=philosophy_dissertations
 Planet Compliance (2016), An introduction to LegalTech or are Smart Contracts the end of Lawyers? https://www.planetcompliance.com/introduction-legaltech-smart-contracts-end-lawyers/
: Investopedia (2015), Can Bitcoin Kill Central Banks? https://www.planetcompliance.com/introduction-legaltech-smart-contracts-end-lawyers/