According to a report released on July 23 by the International Energy Agency Bitcoin (BTC) mining is likely responsible for 10‑20 Metric tons (Mt) of carbon dioxide (CO2) per year or 0.03-0.06% of global energy-related carbon dioxide emissions.
Per the report, the recent price and hash rate increase of the Bitcoin network increased its energy consumption, and it is estimated that during the first six months of 2019 it has already consumed 29 TWh. This is more than the annual energy consumption of Ireland (26 TWh).