This past meteorological summer (June through August) was the Northern Hemisphere’s warmest on record. The new high was also the largest annual increase in global average temperatures, compared with the same period in previous years, according to multiple institutions, including the National Oceanic and Atmospheric Administration.
This September was also the hottest on record globally, according to a report from the European Union’s Copernicus Climate Change Service.
The scorching temperatures were hardly temporary. In many regions, the heat arrived, and stayed, stifling some cities for weeks on end.
Where humidity was high, it felt even hotter than the number on the thermometer indicated, sometimes by more than 10 or 20 degrees Fahrenheit. In such punishing heat, it became dangerous, and even deadly, to be outside, or inside without air conditioning.
The evenings provided little respite. Overnight temperatures were extremely warm, too, making it difficult for many to cool down.
And it is concerning that the planet has seen such unusual warmth before El Niño has peaked, said Zeke Hausfather, a climate scientist at Berkeley Earth, a nonprofit research institute. El Niño is a recurring global climate pattern that is typically linked to warmer conditions in many regions, and its impact is usually most pronounced in the few months after it peaks, which scientists expect will not happen until the start of 2024.
This year’s summer might be relatively cool compared with the ones to come, scientists say, if humans do not slow and eventually halt the burning of fossil fuels, which releases climate-warming greenhouse gases into the atmosphere.
“What we are observing — not only new extremes but the persistence of these record-breaking conditions, and the impacts these have on both people and planet — are a clear consequence of the warming of the climate system,” said Carlo Buontempo, the director of the Copernicus Climate Change Service, in a press release.