Environmental effects of bitcoin
The process of bitcoin mining, by which bitcoins are created and transactions are finalized, is a time-consuming and energy-consuming process that results in carbon emissions and electronic waste. The amount of electrical energy and electronic waste generated by bitcoin mining is often compared with small countries like Ireland or the Netherlands, and the pollution created in this process has a negative effect on Earth's climate and natural environment because the electricity used is at least in part generated through fossil fuels. , bitcoin mining is estimated to be responsible for 0.1% of world greenhouse gas emissions. Estimate on how much energy each individual bitcoin transaction consumes vary, with one claiming approximately 700 kWh, not including energy used in cooling. A 2023 study in the Journal of Public Economics found that "a $1 increase in Bitcoin price leads to $3.11–$6.79 in external damages from carbon emissions alone, well exceeding cryptomining’s value added (using a $190 social cost of carbon, but ignoring increased local air pollution)." An August 2023 study found that bitcoin mining represented about 0.38% of global electricity consumption. Bitcoins are usually mined on specialized computer equipment, some of which has a short useful life expectancy. As of 2021, bitcoin mining was estimated to produce 30,000 tonnes of annual e-waste, which is comparable to the e-waste production of the Netherlands. Carbon emissions 
Concerns about bitcoin's environmental effects relate the network's energy consumption to carbon emissions. Mining as an electricity-intensive process 

Bitcoin mining is a highly electricity-intensive proof-of-work process. Miners run bitcoin-mining software and compete against each other to be the first to win the current 10 minute block and therefore receive the block reward. The bitcoins are the said block reward. The actual "work" being done by these mining computer systems is not useful in any other way. , the Cambridge Centre for Alternative Finance (CCAF) estimates that bitcoin consumes  annually, representing 0.29% of the world's energy production and 0.59% of the world's electricity production, ranking bitcoin mining between Ukraine and Egypt in terms of electricity consumption. George Kamiya, writing for the International Energy Agency, said that "predictions about Bitcoin consuming the entire world's electricity" were sensational, but that the area "requires careful monitoring and rigorous analysis". One study in 2021 by cryptocurrency investment firm Galaxy Digital claimed that bitcoin mining used less energy than the banking system, with Galaxy Digital later clarifying that bitcoin mining's energy usage is not correlated with its "transactional volume or throughput" as it is in banking. Coal power 
Until 2021, according to the CCAF, much of the mining for bitcoin was done in China. Chinese miners relied on cheap coal power in Xinjiang in late autumn, winter and spring, and then migrated to regions with overcapacities in low-cost hydropower, like Sichuan, between May and October. In June 2021 China banned bitcoin mining and the miners moved to other countries. By December 2021, the global computational capacity had mostly recovered to a level before China's crackdown, with more mining being done in the U.S. (35.4%), Kazakhstan (18.1%), and Russia (11%) instead. Coal power plants in Kazakhstan generate most of the country's electricity and emit lots of local air pollution. Greenidge Generation, a power plant in Dresden, New York, had originally been built for coal and had shut down in 2011 due to lack of demand. The plant reactivated in 2016 as a natural gas plant but failed to find sufficient demand. It switched entirely to bitcoin mining in 2019. In addition to emitting around 220,000 tonnes of carbon dioxide in 2020, the plant's cooling intake and discharge of heated water into Seneca Lake coincided with a significant decrease in fish and other wildlife populations. In 2022, the plant's air permit request was denied by the New York State Department of Environmental Conservation (DEC). Renewable energy 
Reducing the environmental impact of bitcoin is possible by mining only using  clean electricity sources. As of September 2021, according to the New York Times, bitcoin's use of renewables ranged from 40% to 75%. Solar photovoltaic electricity generation appears to be the most economic and geographically diverse method of powering mining. Experts and government authorities have suggested that the use of renewable energy for mining may limit the availability of clean energy for ordinary uses by the general population. The Mechanicville Hydroelectric Plant in New York State and three hydroelectric power plants in San Pedro de Poás, Costa Rica have reactivated to mine cryptocurrency. According to the owners of the Mechanicville plant, the mining prevented the plant from being dismantled. Estimates 
The difficulty of translating energy consumption into carbon emissions is due to the way bitcoin mining is distributed, making it difficult for researchers to identify miner's location and electricity use. The results of studies into bitcoin's carbon footprint vary. Per a study published in Finance Research Letters in 2021, the differences in underlying assumptions and variation in the coverage of time periods and forecast horizons have led to bitcoin carbon footprint estimates spanning from 1.2–5.2 Mt  to 130.50 Mt  per year. According to studies published in Joule and American Chemical Society in 2019, bitcoin's annual energy consumption results in annual carbon emission ranging from 17 to 22.9 Mt which is comparable to the level of emissions of countries as Jordan and Sri Lanka. Estimates of energy used per transaction vary. One estimate cited by Columbia University in 2021 says that each bitcoin transaction consumes approximately 707 kWh, not including energy used in cooling which can be significant. Another estimate from MoneySuperMarket.com in 2021 estimates 1,173 KwH, which would be enough to power a US home for several weeks. A 2022 estimate from Digiconomist claims 1,449 kWh per transaction, which would cost approximately USD $173 at average rates. In September 2022, a report in the journal Scientific Reports found that from 2016 to 2021, each US dollar worth of mined bitcoin market value also caused 35 cents worth of climate damage. This is comparable to the beef industry which causes 33 cents per dollar, and the gasoline industry which causes 41 cents per dollar. Compared to gold mining, "Bitcoin's climate damage share is nearly an order of magnitude higher" according to study co-author economist Andrew Goodkind. Electronic waste 

Bitcoins are usually mined on specialized computer equipment, which produces significant e-waste due to its short life expectancy. Bitcoin's annual e-waste is estimated to be over 30,000 tonnes as of May 2021, which is comparable to the small IT equipment waste produced by the Netherlands. One bitcoin generates  of e-waste per transaction. Due to the consistent increase of the bitcoin network's hashrate, mining devices are estimated to have an average lifespan of 1.29 years until they become unprofitable and need to be replaced. Other estimates assume that a bitcoin transaction generates about  of e-waste, equivalent to 2.35 iPhones. Unlike most computing hardware, the used application-specific integrated circuits have no alternative use beyond bitcoin mining. Off-grid bitcoin mining 

Bitcoin has been mined via electricity generated through the combustion of associated petroleum gas (APG), which is a methane-rich byproduct of crude oil drilling that is sometimes flared or released into the atmoshere. Methane is a more efficient greenhouse gas than . By converting more of the methane to  than flaring alone would, using APG generators reduces the APG's contribution to the greenhouse effect, but this practice is still harmful to the environment. In places where flaring is prohibited (such as Colorado) this practice has allowed more oil drills to operate by offsetting costs, which further harms the environment. Mining bitcoin in this way has also allowed oil companies such as ExxonMobile to shift responsibility for emissions onto bitcoin mining companies, without having to address the issue directly. Responses
Some policymakers have called for further restrictions or outright bans on bitcoin mining. A survey on technologies approached cryptocurrencies' technological and environmental issues from many perspectives and noted the plans of using the methods of unconventional computing and grid computing to make bitcoin both greener and more justified. Per a 2021 study in Finance Research Letters, "climate-related criticism of bitcoin is primarily based on the network's absolute carbon emissions, without considering its market value." It argues that the inclusion of bitcoin in an equity portfolio reduces that portfolio's "aggregate carbon emissions". A potential shift from proof-of-work to the more energy-efficient proof-of-stake has been compared to the shift from fossil-fueled to electric vehicles. Proposed pairing with variable renewable energy sources 
The development of intermittent renewable energy sources, such as wind power and solar power, is challenging because they cause instability in the electrical grid. Several papers concluded that these renewable power stations could use the surplus energy to mine bitcoin and thereby reduce curtailment, hedge electricity price risk, stabilize the grid, increase the profitability of renewable energy infrastructure, and therefore accelerate transition to sustainable energy and decrease bitcoin's carbon footprint. Notes

References

Further reading

Economics and climate change
Bitcoin