Cited 7 July 2026: ‘Impossible’ heat | Global ocean record | Climate change and the ozone hole

Welcome to Cited, your essential guide to new climate research. ‘HEAT ALERT’: At least 25 people died as a “heat dome” smothered the eastern half of the US, reported the Guardian, with more than 20 states under “stifling temperatures more than 100F (38C)”. More than 140 million people were under heat alerts, the outlet said, with dead bodies found in “homes with no air conditioning, outside their residences, on the street and in parked cars”. Analysis (WWA) found that the combined heat and humidity would have been “virtually impossible” without human-caused warming, reported the New York Times. ‘MORTALITY WILL RISE FURTHER’: Meanwhile, extreme heat continued to hit Europe, with Le Monde reporting on temperatures of 40C in France, Portugal and Spain again this past weekend, alongside “devastating” wildfires. Public Health France doubled its preliminary estimate of the “excess deaths” from the extreme heat in late June, from 1,000 to more than 2,000, according to the Guardian. The higher figure was still “probably an underestimate”, the agency said. A WWA attribution study, covered , found that Europe’s June heatwave would have been “virtually impossible” even 50 years ago.  ‘BOOST TO GLOBAL TEMPERATURES’: The UN World Meteorological Organization (WMO) “raised its forecast for ​the rapid emergence of a strong El Niño in the coming months, ‌warning that the phenomenon is likely to drive global temperatures higher”, reported Reuters. A WMO scientist told the newswire that “El Niño conditions have emerged ⁠in the equatorial Pacific and there is a remarkable agreement between forecast models that ​this will be a strong El Niño”. On 21 June, global average sea surface temperature (SST) reached a record high for the day of the year, according to the Copernicus Climate Change Service (C3S). Daily SST for the global ocean, excluding polar regions, reached 20.86C on 21 June, exceeding the 20.83C reached on the same day in both 2023 and 2024, the C3S said. Global SST has remained at record levels for every day since. The conditions “could indicate the beginning of a new phase, leading, once more, to uncharted territory”, said C3S director Carlo Buontempo. The amount of time that the average lifespan of tropical cyclones in the north-east and north-west Pacific has shortened, respectively, over 1982-2024, according to a study in npj Climate and Atmospheric Science. This shorter lifespan “compresses the time available for weather forecasting and disaster preparedness”, the authors said. As a new “thought experiment” asks whether the hole in the ozone layer could, theoretically, have been identified decades before it was discovered, Carbon Brief explores the interactions between climate change and the ozone hole.