A thoughtful reader has detected an important error in the hypothetical part of the article calculating the global external costs for electricity and energy in this article, a mistake that escaped both the authors and peer reviewers. In section 3.1, the article presented numbers for global electricity supply when in fact these were for global energy supply. To clarify, global electricity supply in 2018 was 26,566 TWh according to Table 5, which is referred to the World Energy Outlook 2019 from International Energy Agency. However, we stated that global electricity supply was “roughly 14,000 million tons of oil equivalent each year (or 162,820 TWh/year),” a number that reflects total global energy supply, not just electricity. Thus, the corrected expression should appear as: “When our overall externalities estimations are put into the context of global energy supply, which amounts to roughly 14,000 million tons of oil equivalent each year (or 162,820 TWh/year), the results are striking. Using the mean number of 7.152 ¢/kWh, global energy externalities would amount to $11.644 trillion; using the median number (2.328 ¢/kWh), they would amount to $3.79 trillion.” The external costs of “$11.644 trillion” also appear in the abstract and conclusion, where it should be clarified that they refer to global energy supply rather than global electricity supply. When one looks at electricity only—a subset of global energy supply, at only 26,566 TWh/year—the externalities would be a mean of $1.90 trillion; using the median number (2.328 ¢/kWh), they would amount to $0.62 trillion. Interestingly, this would suggest that the externalities from the electricity sector as a whole ($1.90 trillion) are far less than those from transport ($13.018 trillion), almost seven times less. But those from the entire energy system are almost equivalent at $11.644 trillion. No other findings or calculations are affected. The authors would like to apologize for any inconvenience caused.