Earth briefly passed a critical warming threshold this past weekend. According to data from ERA5, the European Centre for Medium-Range Weather Forecasts’ (ECMWF) fifth generation reanalysis of the global climate from 1940 to the present, 17 November 2023 was the first day in which the global temperature exceeded 2°C above pre-industrial levels. These latest figures put Earth’s rising temperatures into sharp focus ahead of COP28, which is set to start in Dubai, United Arab Emirates, on 30 November. Let’s take a closer look at what the ERA5 data shows.

The ERA5 data indicate that the global surface air temperature on 17 November reached 2.07°C above the pre-industrial average, an average temperature taken between 1850-1900 prior to extensive use of fossil fuels. Also, the provisional data for 18 November indicate a temperature anomaly at 2.06°C above the pre-industrial level.

“The ERA5 record now contains two days where global temperatures exceed the pre-industrial level by more than 2°C. That this should happen in the same month that world leaders will gather to take stock of progress towards meeting Paris Agreement commitments at COP28 sends a very clear message – the time for definitive action to tackle climate change is now,” said Copernicus Climate Change Service (C3S) Director Carlo Buontempo. “While exceeding the 2°C threshold for a number of days does not mean that we have breached the Paris Agreement targets, the more often that we exceed this threshold, the more serious the cumulative effects of these breaches will become,” he added.

ERA5 data also reveals that, on 17 November the global surface air temperature was 1.17°C above the average for the 1991-2020 reference period. These record anomalies mean that November 2023 is likely to become the warmest November on record.

These preliminary ERA5 global surface air temperature data are released under ERA5T, were ERA5 data are pre-released with a latency of up to 5 days. These data will now undergo verification before being issued in the final release of ERA5 dataset after the standard 2-3 month quality control period.

C3S has developed an app to help you keep track of global temperatures and their rise towards global warming of 1.5°C. This application monitors the evolution of the global surface air temperature over recent decades until the present, and uses a simple model (with a 30-year linear trend) to estimate the level of global warming at the date up to which the trend is calculated and the date when global warming will reach the 1.5°C limit of the Paris Agreement if the trend continues at that same rate.