Bitcoin's Environmental Impact

In the Spring of 2021, the mining crackdown in China shook up global Bitcoin mining activity. We show that this crackdown may have reduced the use of renewable electricity sources for Bitcoin mining, resulting in increased carbon intensity of mining activities. We estimate that Bitcoin mining may beresponsible for 65.4 MtCO2 annually, which is comparable to country-level emissions in Greece.

The rate of adoption of some cryptocurrencies is triggering alarm from energy researchers and social scientists concerned about the industry’s growing environmental and social impacts. In this paper we argue that the unsustainable trajectory of some cryptocurrencies disproportionately impacts poor and vulnerable communities where cryptocurrency producers and other actors take advantage of economic instabilities, weak regulations, and access to cheap energy and other resources. Globally, over 100 million people hold cryptocurrency, mostly as a speculative asset. The digital infrastructure behind the most popular cryptocurrency, bitcoin, currently requires as much energy as the whole of Thailand, with a carbon footprint exceeding the gold mining industry. Should bitcoin’s mass adoption continue, an escalating climate crisis is inevitable, disproportionately exacerbating social and environmental challenges for communities already experiencing multiple dimensions of deprivation. In mitigating these impacts, the paper considers 4 potential regulatory pathways, including: 1) promoting voluntary private-sector commitments to using only renewable energy, 2) encouraging a system of voluntary carbon offsetting, 3) using existing financial regulations and tax frameworks, and 4) imposing national and/or international bans on cryptocurrency ‘mining’. The paper argues that effective environmental regulation of cryptocurrencies is urgently required, both to reduce the threat of catastrophic climate change, and to help the world’s poorest towards sustainable development. However, regulating cryptocurrency mining in any context is likely to require a combination of efforts and is unlikely to result in win-win outcomes for all.

Bitcoin’s increasing energy consumption has triggered a passionate debate about the sustainability of the digital currency. And yet, most studies have thus far ignored that Bitcoin miners cycle through a growing amount of short-lived hardware that could exacerbate the growth in global electronic waste. E-waste represents a growing threat to our environment, from toxic chemicals and heavy metals leaching into soils, to air and water pollutions caused by improper recycling. Here we present a methodology to estimate Bitcoin’s e-waste and find that it adds up to 30.7 metric kilotons per annum, per May 2021. This number is comparable to the amount of small IT and telecommunication equipment waste produced by a country like the Netherlands. At peak Bitcoin price levels seen early in 2021, the annual amount of e-waste may grow beyond 64.4 metric kilotons in the midterm, which highlights the dynamic trend if the Bitcoin price rises further. Moreover, the demand for mining hardware already today disrupts the global semiconductor supply chain. The strategies we present may help to mitigate Bitcoin’s growing e-waste problem.

The digital currency Bitcoin is known for its energy hunger and associated carbon footprint. Investors, how-ever, must not neglect further environmental, social, and governance issues related to digital currencies. Therefore, we urge the adoption of a more comprehensive view in assessing the externalities of investments in Bitcoin and other cryptocurrencies.

As the price of Bitcoin rises, the negatively externalities associated with Bitcoin mining increase in kind. This article shows how a simple economic model may be used to estimate the potential environmental impact of Bitcoin mining for a given Bitcoin price. These estimates reveal that the record-breaking surge in Bitcoin price at the start of 2021 may result in the network consuming as much energy as all data centers globally, with an associated carbon footprint matching London’s footprint size.

As the resource intensity of running Bitcoin has increased over recent years, it has become a serious concern for its potential impact on health and climate. Within this context, there exists a growing need for accurate information. Various organizations need this for multiple purposes like properly assessing the urgency of the problem, implementing the right policy response in the right locations and for setting up mitigation programs. We propose a market dynamics approach to evaluate the current methods for obtaining information on Bitcoin's energy demand. This allows us to establish that, while historically the Bitcoin mining industry has been growing most of the time, this growth allows market participants to pursue strategies that don't necessarily involve the best devices, device settings, or locations. The bigger the profitability of mining, the more it allows market participants to make decisions that result in suboptimal power efficiency of the Bitcoin network. Specifically, while the profitability of mining peaked during 2019, we find that market participants primarily used older generations of devices with better availability and lower acquisition costs. Common estimation approaches don't only fail to capture this behavior, but also fail to properly capture the market circumstances, like seasonal and geographic variation in electricity prices, that help enable participants to do so in the first place. This combination leaves common approaches prone to providing optimistic estimates during growth cycles. We conservatively estimate the Bitcoin network to consume 87.1 TWh of electrical energy annually per September 30, 2019 (equaling a country like Belgium).

In this paper we find that the Bitcoin network, with an electrical energy footprint of 491.4 to 765.4 kWh per transaction on average, is relatively much more energy-hungry than the traditional financial system. Even though it has been argued that renewable energy may help mitigating the environmental impact of this, we find that there exist fundamental challenges in uniting variable renewable energy production with the consistent demand of Bitcoin mining machines. Moreover, we find that the environmental impact of Bitcoin mining reaches beyond its energy use. Continuous increasing energy (cost) efficiency of newer iterations of mining devices ensures that older ones will inevitably be disposed on a regular basis. The resulting electronic waste generation could equal that of a small country like Luxembourg, with a staggering average footprint of four light bulbs worth of electronic waste per processed Bitcoin transaction. Bitcoin will therefore have to address its sustainability problem in another way. This may consist of replacing its mining mechanism with a greener alternative like Proof-of-Stake.

The electricity that is expended in the process of mining Bitcoin has become a topic of heavy debate over the past few years. It is a process that makes Bitcoin extremely energy-hungry by design, as the currency requires a huge amount of hash calculations for its ultimate goal of processing financial transactions without intermediaries (peer-to-peer). The primary fuel for each of these calculations is electricity. The Bitcoin network can be estimated to consume at least 2.55 gigawatts of electricity currently, and potentially 7.67 gigawatts in the future, making it comparable with countries such as Ireland (3.1 gigawatts) and Austria (8.2 gigawatts). Economic models tell us that Bitcoin’s electricity consumption will gravitate toward the latter number. A look at Bitcoin miner production estimates suggests that this number could already be reached in 2018.