The research from the University of New Mexico, published in the journal Scientific Reports, assessed the climate cost of various commodities as a portion of their overall market cap.
Some, such as coal, cause almost as much damage as the entire value of the market they support, a 95% ratio, according to the analysis. Other commodities, such as pork production, generate huge climate impacts in absolute terms but only because the market is so massive.
Bitcoin, however, lies in between the two. According to the economists, the climate damage of producing the digital currency has averaged 35% of its market value over the past five years, peaking at 82% in 2020.
This week a different study on the climate impacts of bitcoin found the proportion of fossil generation used to power proof of work was far higher than that claimed by advocates.
Combining that data with previous studies on regional differences in electricity generation, the researchers were able to estimate the proportion of generation which is renewable.
However, even though the generation mix is still carbon-intensive, the overall emissions of bitcoin have fallen in the past 12 months because of the sharp decline in the value of the cryptocurrency.
Prices for bitcoin, and therefore the anticipated payouts to miners, have fallen by two-thirds, sending some out of business and leading others to cut their activities, in the process cutting emissions by about 14% compared with 2021, the researchers estimate.
Those emissions are comparable to those of countries such as Nepal or Central African Republic, the Cambridge team says.
