The Earth experienced its hottest day ever in July

A day in July has set the record for the highest average daily temperature on Earth, a figure that takes into account both sea and land temperatures. According to data released by several agencies, such as NASA and Europe’s Copernicus, and the World Meteorological Organization (WMO), the Earth reached 17.16ºCelsius. The previous record — 17.08 degrees — was set in July 2023, which in turn broke the record from August 2016.

It is only a matter of time before this record is broken again, warns Rebecca Emerton, a scientist at the Copernicus climate change service. “As the climate continues to warm, we are set to see new records in the coming years, the question is just how soon it will happen,” she explains. This expert, like other climatologists, also points out that, although there are still months to go, 2024 is shaping up to be the warmest year on record, overtaking 2023.

Although the natural variability of the climate system plays a role, the fact that these records are being broken in such a short time is a reflection of global warming, which has been accelerating in recent decades. According to Copernicus, last July was 1.48 degrees above the average estimated for that month in the pre-industrial period (1850-1900) — in other words, before the massive burning of fossil fuels that release greenhouse gases that overheat the Earth.

When we talk about the highest temperatures recorded to date, we generally refer to the second half of the 19th century, when scientific measurements began to be made. But many paleoclimatologists and the United Nation’s Intergovernmental Panel on Climate Change (IPCC) point out that we have to go back thousands of years to find such high temperatures.

The daily data provided by Copernicus, the Earth observation program funded by the European Union, go back to 1940. These figures record the average air temperature on the planet’s surface two meters above the ground. And, as explained in its July newsletter, last month the planet experienced its two warmest days on record. The average daily global temperature reached 17.16ºC and 17.15ºC on July 22 and 23. But this center clarifies: “Given the small difference, similar to the level of uncertainty in the ERA5 data, we cannot say which of the two days was the hottest with complete certainty.” The ERA5 system is the Copernicus meteorological model that is developed with observation data from satellites and terrestrial sensors.

NASA, for its part, also announced a few days ago that July 22 was the warmest day on record, according to its own measurements. “These record-breaking temperatures are part of a long-term warming trend driven by human activities, primarily the emission of greenhouse gases,” it said. Along the same lines, the World Meteorological Organization reported that this record is “another unwelcome indication of the extent that greenhouse gases from human activities are changing our climate.”

“Extreme heat hit hundreds of millions of people throughout July, with a domino effect felt right across society,” the WMO said. “Widespread, intense and extended heatwaves have hit every continent in the past year. At least ten countries have recorded daily temperatures of more than 50°C in more than one location. This is becoming too hot to handle,” added WMO Secretary-General Celeste Saulo.

2024 on track to be the warmest year on record

For 13 consecutive months (from June 2023 to June 2024), the world’s monthly temperatures have been at record highs. This streak — which is different from the daily record — appears to have ended in July, according to the latest Copernicus data. The average air temperature on the planet’s surface last month was 16.91ºC, just 0.04 degrees below the previous maximum, which was set in July 2023. Again, the difference is so small that it is not entirely clear if it broke the record or not. The WMO did not confirm on Wednesday how it will rank July 2024.

In any case, it is to be expected that, after 13 consecutive months of consecutive monthly records, the streak would break, since El Niño — a natural pattern that causes water surface temperatures in tropical areas of the Pacific to rise and with them those of the entire planet — has ended. “A return to neutral conditions in the tropical Pacific or a shift to La Niña [the opposite phenomenon] should put an end to this additional increase in global average temperatures,” explains Emerton. Although, for the moment, a significant drop in sea temperatures has not been observed either in the Pacific or in other ocean areas.

Despite the expected fall in temperatures in the second half of the year, experts think it very likely that 2024 will go down as the warmest year on record, overtaking 2023. “It seems increasingly likely that 2024 will be warmer than 2023,” says Emerton. The first six months of this year recorded such high temperatures that temperatures would need to fall drastically in the rest of 2024, which has “rarely” occurred, adds this expert. Scientist Zeke Hausfather, from the U.S. organization Berkeley Earth, estimated in a recent article that the probability of 2024 surpassing 2023 is 95%. Copernicus reached the same conclusion in its monthly bulletin: “it [is] increasingly likely that 2024 is going to be the warmest year on record.”

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