http://www.digitaljournal.com/news/environment/bitcoin-causes-carbon-dioxide-emissions-equivalent-to-las-vegas/article/552170

Bitcoin causes carbon dioxide emissions equivalent to Las Vegas

Posted Jun 19, 2019 by Tim Sandle
Research suggests that Bitcoin causes carbon dioxide emissions comparable to a major city, such as Las Vegas or Hamburg. This is based on an analysis of hardware and IP addresses in association with cryptocurrency trading.
Bitcoin  the most widely known cryptocurrency  has seen wild swings in value that have made people c...
Bitcoin, the most widely known cryptocurrency, has seen wild swings in value that have made people cautious about blockchain-based digital money
JACK GUEZ, AFP/File
While Bitcoin may be a virtual currency, the energy consumption associated with the trading of the currency is very real. Technologists based at the Technical University of Munich have undertaken analysis of hardware (from IPO filings) and IP addresses (of of Bitcoin "miners") to assess the carbon footprint of the world's most popular cryptocurrency - Bitcoin. This reveals that the use of Bitcoin causes around 22 megatons in carbon dioxide emissions annually.
The analysis is based on Bitcoin transactions. For a cryptocurrency exchange to be initiated, completed and validated, a mathematical puzzle needs to be solved by each applicable computer for each required stage within the global Bitcoin network. This computing capacity (Bitcoin mining) grows as the number of users of the currency expand. Data from 2018 suggests this process has quadrupled during the course of one year).
An important area of research inquiry is whether the Bitcoin boom is placing an additional burden on the world's climate. Earlier research has shown that the amount of energy required to “mine” one dollar’s worth of bitcoin is over twice that required to mine the same value of copper, gold or platinum.
While earlier data veers towards estimation, the German researchers undertook to provide the most detailed and accurate calculation of the carbon footprint of the Bitcoin system yet conducted.
Through extensive analysis, the researchers calculated the annual electricity consumption by Bitcoin to be about 46 TWh (teraWatts). From this they were able to model how much carbon dioxide is emitted when this energy is generated - the global Bitcoin system has a carbon footprint of between 22 and 22.9 megatons per year. Essential to these computation was understanding where in the world data miners were located (which was 68 percent in Asian countries, 17 percent in European countries, and 15 percent in North America)
The research has been published in the journal Joule, with the peer-reviewed research paper succinctly titled "The Carbon Footprint of Bitcoin."