The carbon emissions generated by bitcoin (BTC) are comparable to the whole of Kansas City, and even a small country, according to a study published in the Joule journal on June 12.

Christian Stoll, one of the researchers involved in the project, said the large energy consumption generated through mining translates into a significant carbon footprint. And, as the computing power needed to solve a bitcoin puzzle has more than quadrupled since last year, it is a problem that is getting worse, the study notes. It adds:

“The magnitude of these carbon emissions, combined with the risk of collusion and concerns about control over the monetary system, might justify regulatory intervention to protect individuals from themselves and others from their actions.”

Researchers used data from IPO filings and IP addresses in order to generate their findings. With annual emissions of CO2 estimated at between 22 and 22.9 megatons, bitcoin is placed somewhere between Jordan and Sri Lanka in international terms. The study suggests that this level would double if every other cryptocurrency was also taken into account.

Stoll, a researcher for the University of Munich and MIT, warned:

“We do not question the efficiency gains that blockchain technology could, in certain cases, provide. However, the current debate is focused on anticipated benefits, and more attention needs to be given to costs.”

Last November, a study reviewing the period from January 2016 to June 2018 found that it took four times more energy to mine $1 of BTC than $1 of copper — and twice as much as it takes to mine $1 of gold or platinum.

A PwC report in March warned that renewable energy would not be enough to solve bitcoin’s sustainability problem. In the same month, a county in the United States state of Montana discussed plans that would nonetheless require crypto miners to use renewable energy.