Climate-driven weather change behind record-breaking heat in 2023

The relationship between anthropogenic climate change and global weather patterns led to the hottest year on record in 2023.

Human-induced global heating combined with other important drivers and feedbacks – including persistent atmospheric blocking, droughts, marine heatwaves and El Niño – caused unprecedented heatwaves in many parts of the planet. 

Writing in Nature Reviews Earth & Environment’s ‘Climate chronicles’ series, 21st Century Weather Chief Investigator Sarah Perkins-Kirkpatrick and her collaborators detailed the extent of the extreme conditions.

The data offers a stark indication of how climate change and rising temperatures are impacting local and global weather conditions.

In 2023, the global average temperature was 1.45°C above pre-industrial (1850–1900) levels, while both the hottest month (July) and hottest season (June to August) ever recorded were experienced.

At a glance:

  • South America suffered between 110 and 150 heatwaves days, with extraordinary events occurring during typically cooler seasons
  • South China’s worst recorded April heatwave occurred
  • In Portugal, Spain and Morocco, temperatures in April were up to 20 degrees higher than normal 
  • Japan experienced its hottest March, July and August since at least 1898

In ‘Climate chronicles’, leading experts outline the observed characteristics and changes to select climate metrics and policies over the course of the year, collectively documenting the state of the climate and its ongoing evolution. 

To read more about the extreme terrestrial heat experienced in 2023, go to:

This research was conducted thanks to ERA5 reanalysis data provided by the Copernicus Climate Change Service

The paper featured contributions from: 

  • David Barriopedro (Instituto de Geociencias, Consejo Superior de Investigaciones Científicas – Universidad Complutense de Madrid)
  • Roshan Jha & Arpita Mondal (IDP in Climate Studies, Indian Institute of Technology Bombay)
  • Lin Wang (Center for Monsoon System Research, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing, China)
  • Renata Libonati (Instituto de Geociências, Universidade Federal do Rio de Janeiro)
  • Kai Kornhuber (Climate Analytics, the Potsdam Institute for Climate Impact Research, and the Lamont-Doherty Earth Observatory, Columbia University)