Earth Had Hottest Three-Month Period on Record, With Unprecedented Sea Surface Temperatures and Much Extreme Weather

The past three months have been the hottest on record, based on data from the European Union-funded Copernicus Climate Change Service (C3S), which is implemented by the European Centre for Medium-Range Weather Forecasts (ECMWF). Global sea surface temperatures have reached unprecedented levels for the third month in a row, while Antarctic sea ice extent remains at an all-time low for this time of year.

August was the hottest on record by a significant margin and ranks as the second warmest month ever, following July 2023. The Copernicus Climate Change Service's ERA5 dataset estimates that August's global temperatures were approximately 1.5°C above the preindustrial average for the period between 1850 and 1900.

From January to August, 2023 ranks as the second warmest year on record, trailing only 2016, which experienced a strong El Niño warming event.

The global average sea surface temperature for August reached 20.98°C, the highest recorded for any month. Every day in August exceeded the previous record set in March 2016.

Antarctic sea ice extent remained at historically low levels for this time of year, measuring 12% below the average. This represents the most significant negative anomaly recorded for August since satellite monitoring began in the late 1970s. Meanwhile, Arctic sea ice extent was 10% below the average, though still well above the record minimum observed in August 2012.

The World Meteorological Organization (WMO) compiles data from C3S and five other international datasets to support climate monitoring efforts and the publication of its State of the Climate reports.

A report released in May by the WMO and the UK Met Office indicated a 98% probability that at least one of the next five years will set a new record for the warmest year. Additionally, there is a 66% chance that, for at least one year within this period, global temperatures will temporarily exceed 1.5°C above the 1850-1900 average. However, this does not signify a permanent breach of the 1.5°C threshold established in the Paris Agreement, which considers long-term warming trends over many years.

Observations and Analysis

Recent data confirms that the planet has experienced its hottest summer on record, indicating the onset of climate instability. Scientists have long warned about the consequences of continued reliance on fossil fuels. The rising temperatures highlight the need for immediate and decisive action to mitigate further climate impacts.

The northern hemisphere faced a summer of extreme weather events, with repeated heatwaves fueling destructive wildfires, harming public health, disrupting daily life, and leaving long-term damage to ecosystems. In the southern hemisphere, Antarctic sea ice extent reached unprecedented lows while global sea surface temperatures broke new records. These developments occurred even before the full effects of the ongoing El Niño event, which typically peak in the second year after its onset.

As of the eighth month of 2023, global temperatures are tracking as the second warmest on record, only slightly cooler than 2016. August alone was estimated to be 1.5°C warmer than preindustrial levels. Beyond individual temperature extremes, the persistence of record-breaking conditions and their consequences for both humans and the environment point to the broader impact of climate system warming.

The data underscore the urgent need for action to address climate change. The increasing frequency and intensity of extreme weather events demonstrate the ongoing consequences of a warming world.