Around 450,000 people worldwide could die by February as a result of hotter weather caused by the record-breaking El Ni帽o, climate scientists are warning. The estimate is based on how many deaths have resulted from past temperature extremes around the world.
鈥淲e鈥檙e hoping this information is actionable, that decisions can be made to move resources ahead of time,鈥� says at the Rhodium Group. This could include assigning health workers to check on the most vulnerable, ensuring people have enough water and providing fans or air conditioning.
Most of the deaths in the next six months will be in the southern hemisphere, because the extra heat will coincide with spring and summer there. But El Ni帽o is expected to persist into the northern hemisphere鈥檚 spring, so there will be another wave of deaths there after February.
Advertisement
鈥淲e鈥檙e going to see anomalously high mortality numbers move north,鈥� says Grover-Kopec. 鈥淚 fully expect these numbers to get bigger, unfortunately.鈥� India and Pakistan could be hit especially hard, she says.
The projection of 450,000 deaths, published in a by the Climate Impact Lab at the University of Chicago, is based on the observed relationship between temperature and excess deaths. This is a U-shaped curve, with more deaths occurring in extreme cold or heat, but its precise shape varies from place to place depending on whether the people and infrastructure are adapted to heat extremes, say, or can afford things such as air conditioning.
A divided the world into 24,000 regions and estimated this relationship for each one, based either on historical data going back decades or on extrapolating from similar regions. Grover-Kopec and her colleagues have now combined this approach with the seasonal forecast from the European Centre for Medium-Range Weather Forecasts (ECMWF) to estimate how many more people than usual could die as a result of heat caused by El Ni帽o.
The results suggest that over the period of the six-month forecast, from September until February, there will be 240,000 additional heat-related deaths. Adding the deaths estimated to have already occurred since the current El Ni帽o started in June takes the total to 450,000.
Africa will be hit hardest, the team estimates, with over 30,000 extra deaths in Nigeria alone in the next six months. There could be 19,000 extra deaths in Indonesia, 16,000 in India and 13,000 in Brazil over the same period.
The report divides people into three age groups: 4 or under, 65 or above, and the rest. 鈥淭here are effects across all three age groups,鈥� says Grover-Kopec. 鈥淭he most sensitive group is that oldest group, followed by the infants.鈥�
鈥淚 do find these results plausible,鈥� says at Indiana University Bloomington. 鈥淓l Ni帽o will bring very high temperatures to much of the world, and the relationship between heat and mortality is consistent and reliable across the world.鈥�
Emergency briefing on the nature and climate crisis
Hear from three of the world鈥檚 leading climate scientists at 麻豆传媒 Live 2026
Callahan recently used a similar approach to estimate that the June heatwave in Europe killed 20,000 people. So far, 35,000 extra deaths in Europe attributable to the heat over a longer period of the summer.
The projection of 240,000 additional deaths between September and February depends on the forecast being right, says Callahan. The ECMWF forecast sits right in the middle of other forecasts, says Grover-Kopec, so it represents a moderate view of what could happen.
The report also looks only at heat-related deaths, Callahan points out. 鈥淓l Ni帽o influences wildfire in Indonesia, infectious disease in South America, flooding in the western US and so on. So, the total death toll may be higher.鈥�
鈥淭he most important message is not the absolute number itself, but what can still be done to reduce preventable harm,鈥� says at the University of Warwick in the UK. 鈥淭he report is best viewed as a call to strengthen anticipatory governance, preparedness and targeted adaptation measures, particularly for at-risk and vulnerable populations.鈥�
