The study, which averages projections from 14 climate models, predicts a temperature surge of roughly 4 °C above the long‑term average by November. That spike has led scientists to forecast that 2027 could become the hottest year ever documented.
Among the report’s most stark findings is an estimate that 451,000 people could die as a result of extreme heat under the projected conditions. Greenstone described the figure as “numbing,” emphasizing that it represents a cross‑section of parents, children, grandparents, workers and neighbours whose lives could be cut short.
Looking ahead, Greenstone urged immediate action, saying that within the next 20 years today’s extreme temperatures are likely to become the new normal. He called for the rapid design, deployment and evaluation of tools that can protect lives as the climate crisis intensifies.
The report adds a mortality dimension to existing climate warnings, underscoring the human cost of unchecked warming. By quantifying potential deaths, the authors aim to shift policy focus toward concrete life‑saving interventions rather than abstract temperature targets.
Greenstone concluded that the new analysis “opens the door” to prioritising death prevention as the most important outcome of climate policy, urging governments and stakeholders to mobilise resources now to avert the projected loss of life.