This calculator is based on the scientific research of R. Daniel Bressler (https://www.nature.com/articles/s41467-021-24487-w). You can use it at https://onnoniem.github.io/carboncalculator/.
CO2 emission factors are taken from https://www.co2emissiefactoren.nl/lijst-emissiefactoren/. We use tank-to-wheel values; the actual emissions are worse because of the well-to-tank values. We may implement that in the future.
The mortality cost as calculated by Bressler only accounts for temperature-related mortality (i.e. the net mortality impact of more hot days and fewer cold days). This calculation leaves out potentially important climate-mortality pathways such as the effect of climate change on infectious disease, civil and interstate war, food supply, flooding, and the effects of particulate matter and other local pollutants. Therefore, the real mortality cost is probably higher. Also, the emissions of aviation at high altitutes cause more warming than emissions at ground level.
Disclaimer: we did the best we could but it is possible that this calculator contains errors. If you think you found an error, please let us know by submitting an issue (or a pull request) on Github. Please include reliable sources. (The fossil industry is not a reliable source.)