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A very hot September is bringing the world ever closer to the first crucial warming threshold: for a third of the days in 2023, the average global temperature was at least 1.5°C higher than pre-industrial levels. Staying below this threshold is considered essential by scientists to avoid the most disastrous impacts of the greenhouse effect. There have been other episodes of exceeding the 1.5°C limit in the modern era, but it has never happened for such a long period of the year. Not surprisingly, 2023 is on track to be the warmest year on record.
Data from the Copernicus Climate Change Service shows that in the first nine months of this year, average global temperatures exceeded the limit of 1.5°C compared to pre-industrial levels for approximately 86 days. The first time that average global temperatures exceeded this threshold happened for a few days in December 2015, just as UN countries were signing the Paris climate agreement. Political leaders meeting in Paris in December 2015 committed to keeping the increase in global temperatures this century “well below” 2°C and to make every effort not to exceed the 1.5°C threshold. Since then the 1.5°C limit has been repeatedly exceeded, usually only for short periods. In 2016, in the wake of El Niño – a natural weather oscillation that tends to increase global temperatures – the world recorded around 75 days above the 1.5°C threshold.
Buontempo (Copernicus): record September
Now 2023 has broken 2016’s record, well before the end of the year. This finding comes after a very hot September and a summer of extreme weather events across much of the world, from fires in Greece, Canada and Hawaii to floods in Libya, China and the Philippines. “We experienced the most incredible September in history from a climate point of view,” explained Carlo Buontempo, director of the Copernicus Climate Change Service, to AFP. «It’s nothing new this year: we had record June, July and August. September fits very well into this extreme model” explains Buontempo. The specific average recorded temperature is well half a degree above the hottest September ever certified, which was 2020, and 1.75°C above the pre-industrial level. «Now we are in a new dimension … the largest anomaly we have ever seen in any month in our data – he says. – The massive loss of sea ice in Antarctica is part of it” notes Buontempo, pointing out that “nothing similar” has never been recorded not only in his professional experience, “but in living memory and in all likelihood in our history of human beings on this planet.”
El Nino effect but not only that
According to Buontempo, therefore, «climate change is not something that will happen in ten years… climate change is already here». As for the reasons behind this record heat, the director of the Copernicus Climate Change Service observes that «there is a series of cumulative factors.” In this context, “El Nino certainly plays a role in the increase in Pacific temperatures”, but for Buontempo “the anomaly is not isolated to the Pacific, so it is not just El Nino”. “The Atlantic has also been incredibly warm, with heat waves in June and July… and the large loss of sea ice in Antarctica may have contributed.” According to Buontempo, “all this is caused by anthropogenic climate change.” The overheating in the past month was not unexpected. However, Buontempo underlines, “the speed of some changes and the anomaly we observed this year took many scientists by surprise.”
On the possible exceeding of the 1.5°C limit in 2023, the director of the Copernicus Climate Change Service specifies that “it is not certain that the annual average will get there, but we are quite close”. According to the Copernicus Climate Change Service, the year-to-date global average temperature is about 1.4°C above the pre-industrial average. But “it is very likely that in the next five years the world will reach 1.5°C for an entire year” as already clarified by the United Nations World Meteorological Organization. For the Paris Agreement it is not significant to exceed this threshold for a day or a week or even for a year, but instead the average of 20 or 30 years counts. This long-term average is currently between 1.1°C and 1.2°C, but the more often the 1.5°C threshold is exceeded on individual days, the closer the world comes to surpassing this threshold long-term.