A 2018 study published in Nature Climate Change estimated that if Bitcoin were broadly adopted for cashless transactions, its associated energy consumption could alone produce enough carbon dioxide emissions to push global mean temperatures past 2°C within 30 years. Critics challenged the methodology immediately, arguing the projections excluded unprofitable hardware, failed to account for shifts in the electricity generation fuel mix, and assumed adoption trajectories that outpaced historical precedent for any payment technology. The methodological dispute was legitimate. What it obscured was the underlying direction of the data.