Provisional State of the Global Climate 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.
• Record monthly global temperatures have been observed for the ocean – from April through to September – and, starting slightly later, the land – from July through to September.
• The ten-year average 2014–2023 (to October) global temperature is 1.19±0.12°C above the 1850–1900 average, the warmest 10-year period on record.
• Observed concentrations of the three main greenhouse gases – carbon dioxide, methane, and nitrous oxide – reached record-high levels in 2022, the latest year for which consolidated global values are available (1984–2022). Real-time data from specific locations show that levels of the three greenhouse gases continued to increase in 2023.
• Ocean heat content reached its highest level in 2022, the latest available full year of data in the 65-year observational record.
• In 2023, global mean sea level reached a record high in the satellite record (1993 to present), reflecting continued ocean warming as well as the melting of glaciers and ice sheets. The rate of global mean sea level in rise in the past ten years (2013–2022) is more than twice the rate of sea level rise in the first decade of the satellite record (1993–2002).
• Antarctic sea-ice extent reached an absolute record low for the satellite era (1979 to present) in February. Ice extent was at a record low from June onwards, and the annual maximum in September was far below the previous record low maximum.
• Glaciers in western North America and the European Alps experienced an extreme melt season. In Switzerland, glaciers lost around 10% of their remaining volume in the past two years.
• Extreme weather continues to lead to severe socio-economic impacts. Extreme heat affected many parts of the world. Wildfires in Hawaii, Canada and Europe led to loss of life, the destruction of homes and large-scale air pollution. Flooding associated with extreme rainfall from Mediterranean Cyclone Daniel affected Greece, Bulgaria, Türkiye, and Libya with particularly heavy loss of life in Libya.
• Food security, population displacements and impacts on vulnerable populations continue to be of concern in 2023, with weather and climate hazards exacerbating the situation in many parts of the world.
• Extreme weather and climate conditions continued to trigger new, prolonged, and secondary displacement in 2023 and increased the vulnerability of many who were already uprooted by complex multi-causal situations of conflict and violence.