New Scientist reports that Emily Grover-Kopec and her team’s projection was published in a report by the Climate Impact Lab at the University of Chicago. The outlet says the estimate is based on past relationships between temperature extremes and excess deaths, combined with a seasonal forecast from the European Centre for Medium-Range Weather Forecasts. That makes it a projection derived from temperature-mortality relationships and seasonal forecasting, not an observed global death count.
Of that total, 240,000 additional heat-related deaths are projected during the six-month window from September through February, New Scientist reports. The rest of the 450,000 figure comes from deaths the researchers estimated had already occurred since the current El Niño started in June.
Where the model points hardest
According to New Scientist, the researchers estimate that Africa will be hit hardest. The article says there could be over 30,000 extra deaths in Nigeria alone in the next six months. It also cites country-level estimates of 19,000 in Indonesia, 16,000 in India and 13,000 in Brazil over the same period.
New Scientist also reports that the model divides people into three age groups: children 4 and under, adults 65 and older, and everyone else. Grover-Kopec told the outlet that all three groups are affected, with older adults the most sensitive group, followed by infants.
Why experts say the number is incomplete
Outside experts quoted by New Scientist described the findings as plausible while stressing their limits. Christopher Callahan of Indiana University Bloomington told the magazine that the September-to-February projection depends on the forecast being right. He also said the overall toll may be higher because the report counts only heat-related deaths.
As New Scientist quotes him, El Niño can also affect wildfire risk in Indonesia, infectious disease in South America and flooding in the western U.S. Those pathways are not included in the estimate, so the 450,000 figure is a projection tied specifically to heat-related mortality.
Raquel Nunes of the University of Warwick told New Scientist that the most important message is not the absolute number itself but what can still be done to reduce preventable harm, especially for vulnerable populations.
What the evidence supports, then, is not that 450,000 people have already died, but that researchers are warning of a large projected heat-related toll that depends on forecast accuracy and does not include non-heat impacts associated with El Niño. Source
