Last year was the hottest on record, averaging 1.48°C warmer than the period before people started burning fossil fuels, according to data from Copernicus.
The EU's Earth observation programme said the global average temperature throughout the year was 14.98°C, overtaking 2016, the previous warmest year, by “a large margin”.
That was 0.17°C higher than in 2016 and 1.48°C warmer than the 1850-1900 pre-industrial level, putting it perilously close to the world’s target to restrain the global temperature rise to 1.5°C above pre-industrial level to limit the impact of heatwaves, drought, flooding and other calamities that result from climate change.
Copernicus, an EU programme aimed at developing European information services based on satellite data, said temperature averages reached more than 2°C above pre-industrial levels – the upper limit of a threshold set by the Paris Agreement in 2015 – on two occasions.
The data shows about half of the days throughout the year were more than 1.5°C warmer than the 1850-1900 level. And two days in November were, for the first time, more than 2°C warmer.
Forecasters had previously tipped the year to finish at an average of 1.2°C above pre-industrial levels.
Akshay Deoras, a research scientist at the National Centre for Atmospheric Science and the Department of Meteorology at the University of Reading, told The National the fact so many days were 1.5°C or above the pre-industrial average was concerning and further proof greenhouse gases were worsening climate change.
“If this happens on a few days in a year, that’s fine because there are anomalies,” he said.
“But given that so many days have seen unusual heat is concerning. That is telling you it is not a weather anomaly. It’s not related to [a natural] climate pattern.”
Samantha Burgess, deputy director of the Copernicus Climate Change Service, said 2023 was an exceptional year, “with climate records tumbling like dominoes”.
“Not only is 2023 the warmest year on record, it is also the first year with all days over 1°C warmer than the pre-industrial period,” she said.
“Temperatures during 2023 likely exceed those of any period in at least the last 100,000 years,” she said.
She told a press conference on Tuesday about the report that the world is likely to overshoot the target of 1.5°C of warming.
“That is basic physics of the system and the amount of warming that is locked into the system,” she told a press conference on Tuesday.
“However, the reality is that every single fraction of a degree matters and we know the warmer our atmosphere, the warmer our climate, the more intense and the more frequent the extreme events are.”
Greenhouse gas concentrations fuelled the record temperatures, but El Nino, which typically results in around 0.1°C of additional warming, plus record high surface ocean temperatures also played a part.
The data confirms predictions from the World Meteorological Organisation, which said a series of temperature records meant it was “virtually certain” that 2023 would become the hottest year on record.
A report from WMO found April through to October had record high monthly temperatures in the oceans, while July was the likely the hottest on land in the last 120,000 years.
The year had a string of natural disasters, including extreme flooding from Storm Daniel, which killed thousands of people in Libya, wildfires in Canada that burnt 18.5 million hectares – an area bigger than England and Wales – and severe drought in Uruguay that emptied its reservoirs and pushed the country close to running out of fresh water.
Annual average air temperatures were the warmest on record, or close to the warmest, over sizeable parts of all ocean basins and all continents except Australia, said Copernicus.
The data showed July and August 2023 were the warmest two months on record.
December was the warmest on record historically, with temperatures 1.78°C above the 1850-1900 level for the month.
Global average sea surface temperatures remained persistently and unusually high during the year, reaching record levels for the time of year from April through December.
Sea ice in the Antarctic was also at a record low.
This year could also be another record-breaking year.
It is “likely” a 12-month period ending in January or February of this year will exceed 1.5°C above pre-industrial levels, the weather service said.
The UK's Met Office also predicted average global temperatures could rise higher than 1.5°C throughout the year.
El Nino, a naturally occurring phenomenon in which heat rises in the tropical eastern Pacific Ocean, adding further heat to the atmosphere in 2023, is set to continue into spring.
“Historically, years following El Nino have been really hot, such as 2016 and so on, which means that this year in the first six months there is a very good possibility that we would continue to see individual months breaking previous records,” Mr Deoras told The National.
Climate models indicate La Nina – the periodic cooling of sea-surface temperatures across the east-central equatorial Pacific – may follow in the summer, resulting in colder-than-normal temperatures, albeit temporarily, he said.
“It used to happen in the past that whenever we had La Nina you could see a decline in the temperature for some time. But now that doesn't really happen,” said Mr Deoras.
“The whole thing is more and more driven by greenhouse gases. If La Nina happens, it will be interesting to see how much it can offset this additional heating which was there because of El Nino.
“The background pattern of greenhouse gases is still going to be dominating, which means you will continue to have at least some years in the next 10 years where previous records will be broken.”
