2023 on track to be the warmest year on record – September 2023 warmest ever yet

Globally averaged surface air temperature anomalies relative to 1991–2020 for each September from 1940 to 2023. Data source: ERA5. Credit: Copernicus Climate Change Service/ECMWF.

According to the Copernicus Climate Change Service (C3S) September 2023 has been the hottest ever recorded since 1940 and 2023 is on course to become the hottest year since records began.

Below are the highlights:

• September 2023 was the warmest September on record globally, with an average surface air temperature of 16.38°C, 0.93°C above the 1991-2020 average for September and 0.5°C above the temperature of the previous warmest September, in 2020.
• September 2023 global temperature was the most anomalous warm month of any year in the ERA5 dataset (back to 1940).
• The month as a whole was around 1.75°C warmer than the September average for 1850-1900, the preindustrial reference period.
• The global temperature for January-September 2023 was 0.52°C higher than average, and 0.05°C higher than the equivalent period in the warmest calendar year (2016).
• For January to September 2023, the global mean temperature for 2023 to date is 1.40°C higher than the preindustrial average (1850-1900).
• For Europe, September 2023 was the warmest September on record, at 2.51°C higher than the 1991-2020 average, and 1.1°C higher than 2020, the previous warmest September.
• The average sea surface temperature for September over 60°S–60°N reached 20.92°C, the highest on record for September and the second highest across all months, behind August 2023.
• El Niño conditions continued to develop over the equatorial eastern Pacific.

Global daily surface air temperature (°C) from 1 January 1940 to 30 September 2023, plotted as time series for each year. 2023 and 2016 are shown with thick lines shaded in bright red and dark red, respectively. Other years are shown with thin lines and shaded according to the decade, from blue (1940s) to brick red (2020s). The dotted line and grey envelope represent the 1.5°C threshold above preindustrial level (1850–1900) and its uncertainty. Data source: ERA5. Credit: Copernicus Climate Change Service/ECMWF.

According to Samantha Burgess, Deputy Director of the Copernicus Climate Change Service (C3S): “The unprecedented temperatures for the time of year observed in September – following a record summer – have broken records by an extraordinary amount. This extreme month has pushed 2023 into the dubious honour of first place – on track to be the warmest year and around 1.4°C above preindustrial average temperatures. Two months out from COP28 – the sense of urgency for ambitious climate action has never been more critical.”

Source: Copernicus Climate Change Service

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Saima Baig

I am a Chartered Environmentalist from the Royal Society for the Environment, UK and co-owner of DoLocal Digital Marketing Agency Ltd, with a Master of Environmental Management from Yale University, an MBA in Finance, and a Bachelor of Science in Physics and Mathematics. I am passionate about science, history and environment and love to create content on these topics.