Addendum A to Part 1 and Part 2
Climate-related death tolls associated with the previous “briefing” posts—Part 1 of 2 (The Road to Net Zero) and Part 2 of 2 (Net Zero Plus Carbon Removal)—is a 6-page PDF laid out like the two “briefings.” It re-draws earlier CO₂ chart created by Claude following my instructions, with the “briefing” scenarios and adds a single climate-deaths graph.
To keep everything in sync, Claude rebuilt the same kind of carbon-cycle and climate model the “briefings” use. It reproduces their key figures closely: CO₂ peaking around 483 ppm on the realistic path and 463 ppm with carbon removal, and warming peaking around 2.1 °C and 1.9 °C. Claude then ran the “net zero by 2050” path through it as a fourth scenario.
Deaths are tied to each path’s warming. The low end of the range is matched to Bressler (2021) and the high end to Carleton et al. (2022), and the result checks out against the Lancet Countdown’s figure for today’s heat deaths.
What the deaths graph shows:
- Today: about 350,000 deaths a year (range 220,000–575,000), counting deaths from heat and temperature only.
- 2026 to 2050: about 15 million deaths on every path. Warming lags emissions, so the next 25 years are largely locked in.
- Total by 2100:
| Path | Deaths, 2026–2100 |
|---|---|
| Emissions stay flat | ~87 million |
| Realistic net zero (~2074) | ~66 million |
| Net zero by 2050 | ~52 million |
| Net zero + carbon removal | ~37 million |
- The key message: net zero stops the annual rate of death from rising but not the dying—millions of people continue to die. Deaths level off at roughly 0.75–1 million a year and stay there. Only cooling brings them back down.
These scenarios sit at the low end of the risk. They leave out climate tipping points, such as ice-sheet collapse, permafrost thaw and a shutdown of the Atlantic ocean circulation, because their timing is still debated. That uncertainty is not a reason to wait. It is a warning that argues for speed and early action rather than further delay.
Chart A-1
Chart A-2
