Copernicus: October 2023 – Exceptional temperature anomalies. It is already certain, this year will be the warmest year in the history of measurements

Globally averaged surface air temperature anomalies relative to the period 1991-2020 for each October in 1940-2023. Data source: DATA SOURCE: ERA5. Credit: C3S/ECMWF.

The Copernicus Climate Change Service (C3S), which is implemented on behalf of the European Commission by the European Center for Medium-Range Weather Forecasts with financial support from the EU, regularly issues monthly climate bulletins in which it reports on observed changes in global air and sea surface temperatures , sea ​​ice cover and hydrological variables . All reported findings are based on computer analysis and the ERA5 dataset, which uses billions of measurements from satellites, ships, aircraft and weather stations around the world.

October 2023 – Highest values ​​of ground air and sea surface temperature:

• October 2023 was the warmest October on record globally, with an average land surface air temperature of 15.30 °C, 0.85 °C above the 1991-2020 average October and 0.40 °C above the previous warmest October in 2019.
• The global temperature anomaly for October 2023 was the second highest of any month in the ERA5 dataset, after September 2023.
• The month as a whole was 1.7°C warmer than the estimated October average for the period 1850-1900, which was set as the pre-industrial reference period.
• In the calendar year to date, from January to October, the average global temperature for 2023 is the highest on record, 1.43°C higher than the pre-industrial average from 1850-1900 and 0.10°C higher than the 2016 ten-month average , which is currently the warmest calendar year on record.
• For Europe, October 2023 was the fourth warmest October on record, 1.30°C higher than the 1991-2020 average.
• The average sea surface temperature in October over 60°S – 60°N was 20.79 °C, the highest temperature recorded for October.
• In the equatorial Pacific, El Nino conditions continued to develop, although anomalies remain lower than this time of year during the development of historically strong events in 1997 and 2015.

Monthly global surface air temperature (°C) anomalies relative to the period 1991-2020 from January 1940 to October 2023, plotted as a time series for each year. The year 2023 and the year 2016 are represented by thick lines shaded in light red, respectively. dark red color. Other years are represented by thin lines and shaded by decade, from blue (1940s) to brick red (2020). Data source: DATA SOURCE: ERA5. Credit: Copernicus Climate Change Service/ECMWF.

According to Samantha Burgess, Deputy Director of the Copernicus Climate Change Service (C3S): “October 2023 saw exceptional temperature anomalies, which followed four months of global temperature records being broken. It is almost certain that 2023 will be the warmest year on record and is currently 1.43°C warmer than pre-industrial average. The sense of urgency for ambitious climate action ahead of COP28 has never been greater.”

Global daily sea surface temperature (°C) from 1 January 1940 to 31 October 2023, plotted as a time series for each year. The year 2023 and the year 2016 are represented by thick lines shaded in light red, respectively. dark red color. Other years are represented by thin lines and shaded by decade, from blue (1940s) to brick red (2020).: DATA SOURCE: ERA5. Credit: C3S/ECMWF.

October 2023 – Sea Ice Highlights:

• October was the sixth month in a row that Antarctic sea ice extent remained at a record low for the time of year, with the monthly value 11% below average.
• Arctic sea ice extent hit the seventh lowest in October, 12% below average.

October 2023 – Main communication on hydrological variables

• In October 2023, rainfall was above average in most of Europe: northern Europe was hit by storm Babet and Portugal and Spain by storm Aline, which brought heavy rainfall and flooding.
• Outside of Europe, several areas experienced above-average wet weather, including southwestern North America, parts of the Arabian Peninsula, areas of central Asia and Siberia, southeastern China, Brazil, New Zealand, and areas of southern Africa. These conditions were often associated with the passage of cyclones that produced heavy rainfall and significant damage.
• Above-average drought was experienced in the southern United States and parts of dry Mexico, areas of central and easternmost Asia, and most of the extratropical Southern Hemisphere, including Australia.