Record Breaking Heat
The Art
The Science
Global Mean Temperature Difference 1850-2023
“Key messages:
The global mean near-surface temperature in 2023 (to October) was around 1.40 ± 0.12 °C above the 1850–1900 average. Based on the data to October, it is virtually certain that 2023 will be the warmest year in the 174-year observational record, surpassing the previous joint warmest years, 2016 at 1.29 ± 0.12 °C above the 1850–1900 average and 2020 at 1.27±0.13 °C.
The past nine years, 2015–2023, will be the nine warmest years on record.
Global mean near-surface temperature in 2023 (data to October) was 1.40 ± 0.12 °C above the 1850– 1900 average8 (Figure 2). … Based on the data to October, it is virtually certain that 2023 will be the warmest year in the 174-year instrumental record in each of the five data sets. The most recent nine years – 2015 to 2023 – will be the nine warmest years on record. The two previous joint warmest years were 2016 with an anomaly of 1.29 ± 0.12°C, and 2020 with an anomaly of 1.27 ± 0.13°C.
There were some noteworthy individual months, with June, July, August, and September 2023 each surpassing the previous record for the respective month by a wide margin in all datasets. The margin increased from between 0.14 and 0.20 °C in June to between 0.46 and 0.51 °C in September. The second-highest margin by which a September record was broken in the past 60 years (the period covered by all datasets) was 0.02 to 0.17°C in 1983. October was also record warm. July is typically the warmest month of the year globally, and thus July 2023 became the all-�me warmest month on record.
The long-term increase in global temperature is due to increased concentrations of greenhouse gases in the atmosphere. The shift from La Niña, which lasted from mid-2020 to early 2023, to fully developed El Niño conditions by September 2023 …likely explains some of the rise in temperature from 2022 to 2023. However, some areas of unusual warming … do not correspond to typical paterns of warming or cooling associated with El Niño. Other factors, which are still being investigated, may also have contributed to the exceptional warming from 2022 to 2023. ..”
Provisional State of the Global Climate 2023
World Meteorological Organization
