The string of months with record temperatures throughout 2023 already predicted that globally it was going to be the hottest year since records began. A forecast that the European climate change service Copernicus has confirmed on Tuesday after analysing all the available data. Not only is 2023 officially the hottest year since measurements began in 1850, but the increase in global average temperature over this period has been close to 1.5 degrees Celsius compared to what it was at the beginning of the industrial era.

According to the 2023 climate report released on Tuesday, "unprecedented global temperatures starting in June made 2023 the warmest year ever recorded, surpassing 2016," the hottest year so far. Thus, the global average temperature was 14.98 °C, which is 0.17 °C higher than the previous highest annual value, measured in 2016.

If we make a more long-term comparison, it was 0.6 ºC warmer than the average recorded between 1991 and 2020, and 1.48 ºC hotter than the average recorded during the pre-industrial period (between 1850 and 1900).

"2023 was an exceptional year in which weather records fell like dominoes. Not only is it the warmest year on record, but it is also the first year in which all its days exceeded the global average temperature of the pre-industrial period by one degree," said Samantha Burgess, Deputy Director of the Copernicus Climate Change Service. The scientist also highlights that "temperatures during 2023 are likely to exceed those of any period in at least the last 100,000 years".

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The first signs of how unusual 2023 was going to be appeared in early June, when temperature anomalies relative to the pre-industrial level of 1850-1900 reached 1.5°C for several days in a row. Although it wasn't the first time daily anomalies had reached this level, it had never happened at that time of year before. For the rest of 2023, daily global temperature anomalies above 1.5°C became commonplace, to the point that almost half of the days in 2023 exceeded the temperature of the 1-5 period by 1850.1900°C and there were two days in November when for the first time, The two degrees of increase were reached.

According to the Copernicus scientists, "this does not mean that we have exceeded the limits set by the Paris Agreement (since they refer to periods of at least 20 years in which this average temperature anomaly is exceeded) but it sets a disastrous precedent".

The report is peppered with other data reflecting how unusual last year was. From June to December, each month of 2023 was hotter than those same months in previous years. July and August 2023 were globally the hottest months on record, as was summer (June to August), the warmest.

The year ended with a December that was also the hottest on record for that period, with an average temperature of 13.51 ºC, which is almost one degree more (0.85 ºC) compared to the average between 1991 and 2020, and 1.78 ºC more than the pre-industrial era.

Data in Europe

Although Mauro Facchini, Director of Earth Observation at the European Commission's Directorate-General for Defense Industry and Space, did not expect good news, he believes that "the annual data presented offer even more evidence about the growing impacts of climate change." As Facchini recalls, the European Union has committed, in line with the best available science, to reduce greenhouse gas emissions by 55% by 2030: "There are only six years left and the challenge is clear," he warned.

If we focus on Europe, 2023 was the second warmest year, 1.02ºC above the 1991-2020 average and 0.17ºC cooler than 2020, the warmest year on record on the continent. Temperatures in Europe were above average for 11 months of 2023 and September was the warmest September on record.

The winter (December 2022-February 2023) ranks in Europe as the second warmest since records began. The summer (June-August) was also very hot, with an average temperature of 19.63°C, which is 0.83°C above average, making it the fifth warmest on record.

The European autumn (September-November) also had an average temperature above average (1.43 ºC more) at 10.96 ºC. These records made it the second warmest autumn ever recorded, only 0.03°C colder than autumn 2020.

Extreme events

The scientists also highlight "the large number of extreme events that were recorded around the globe, including heat waves, floods, droughts and forest fires". In fact, carbon emissions linked to wildfires were up 30% compared to 2022, mainly due to the massive fires in Canada.

The Copernicus report also includes the concentrations of the main greenhouse gases, which reached record levels in 2023. Thus, those of carbon dioxide (CO2) were 2.4 ppm (particles per million) higher than those measured in 2022, while those of methane increased by 11 ppb (parts per billion). Specifically, CO2 emissions reached 419 parts per million and methane prices reached 1,902 parts per billion (a figure that is still high but represents a lower growth rate than in the last three years).

Marine Heat Waves

Another of the climatic characteristics of 2023 was the numerous marine heatwaves, which affected regions such as the Mediterranean, the Gulf of Mexico, the Caribbean, the Indian Ocean, the North Pacific and much of the North Atlantic. As the report points out, the global average temperature of the oceans between April and December was the highest recorded in the database.

The main long-term factor explaining such high ocean temperatures is the increase in greenhouse gas concentrations, but another contributor has been the effect of the El Niño phenomenon, a natural climate variability that began to develop from July 2023 and whose effects will become more acute in 2024.

And this warming trend doesn't look like it's going to reverse this year. As the prestigious former NASA climate scientist James Hansen has pointed out to The Guardian, the current situation will be aggravated by El Niño, which could cause an increase in the global average temperature of 1.7 degrees Celsius by May compared to what it was before the industrial era.

However, Copernicus scientists stress that the El Niño phenomenon alone does not explain the increase in ocean surface temperature.

So it hasn't been a good year for the ice at the poles either. Antarctica saw record minimum extents in eight months compared to the same time of year. Both daily and monthly ice sheet extent reached record lows in February 2023.

As far as the Arctic is concerned, sea ice extent in March, when it reaches its annual maximum, was among the four lowest for that time of year in the satellite record. September's yearly low was the sixth-lowest.