According to a new preprint conducted by researchers at the Netherlands' Open Universiteit and Radboud University, in addition to the University of California, Berkley, the vast majority of literature on blockchain energy use from both academic and everyday sources lacks “the scientific rigor expected from a mature scientific field.” The report analyzed 128 scientific and open-source studies related to carbon emissions of blockchains such as Bitcoin.

Researchers found that an astonishing 34% of studies did not even possess an explicit research design. Meanwhile, 43% of studies did not share data, while 67% did not share source code. Finally, 79% of studies had no discussions about the reliability of external data.

Several notable fallacies across studies were discovered by researchers in their analysis. First off, blockchain energy studies typically cite data and derive their conclusions from the Cambridge Bitcoin Electricity Consumption Index. However, the source explicitly states that it only captures about 32% to 37% of all computing power in the network. 

Secondly, the validity of electricity costs used in such studies is called into question. Researchers found that a significant portion of studies had “no clear” assumptions for cost of electricity use in cryptocurrency mining. Furthermore, there is considerable opacity within studies regarding their choice of power usage effectiveness.

Finally, researchers flagged the validity of blockchain carbon emission claims. In several studies, they found that the earlier investigators, with no empirical evidence, simply extrapolated carbon emissions data from 2014 and applied it to 2017; from 2019 and applied it to 2021; from 2015 and applied it to 2020, and so on.

The report called for discussions regarding the reliability of models assessing the environmental impacts of blockchains. The crypto community remains heavily divided when it comes to assessing the carbon footprint of blockchains. Some, such as Miami Mayor Francis Suarez, say that 90% of energy from Bitcoin mining comes from dirty energy. Others claim that the network accounts for less than 0.08% of the world's carbon dioxide production.