The latest information on the global climate state has been released in the publication “The State of the Climate 2024”. Contributions from scientists worldwide, including the CSIR’s Dr Sandy Thomalla and affiliate Dr Tommy Ryan-Keogh, are captured with the top scientific findings, highlighting the continuation of concerning global warming trends.

The extent to which global climate, global oceans, the tropics, the Arctic, Antarctica and the Southern Ocean and regional climates are being affected by changing climatic conditions is outlined in the 513-page report, available as a special supplement to the Bulletin of the American Meteorological Society, 106(8), August 2025. It provides detailed updates on global climate indicators, notable weather events and other data collected by environmental monitoring stations and instruments located on land, water, ice and in space, driving home the message that 2024 was one of the warmest years on record.

“I led the Southern Ocean section in Chapter 6, titled ‘Antarctica and the Southern Ocean’, where the state of the Southern Ocean in 2024 was assessed relative to historical climatology by examining its sea surface temperature, salinity and mixed layer properties, air-sea heat flux, upper ocean heat content and ocean biogeochemistry. Our observations reveal that the Southern Ocean experienced substantial warming, continuing the warming trend of recent years with the ocean heat content reaching its highest level to date,” Thomalla says.

By focusing on its ability to absorb heat and carbon, Thomalla and Ryan-Keogh’s contributory findings emphasise the Southern Ocean’s disproportionately large role in regulating Earth’s climate due to ongoing and evolving atmospheric-ocean dynamics.

New climate and weather records were reached in 2024. The report notes that the Earth continued to become hotter, fuelled by a strong El Niño at the beginning of 2024 and later transitioning to neutral conditions. Major greenhouse gases continued to escalate, with a growth from 2023 to 2024 of 3.4 parts per million, equal to the observed change between 2015 and 2016, which is the highest on record since the 1960s.

Although Thomalla and Ryan-Keogh focused on the Southern Ocean, observations of interest in southern Africa include those for South Africa. Extreme heatwaves affected various parts of the region throughout the year, with South Africa being particularly affected in May, while many central and eastern areas were affected during December, resulting in monthly mean temperature anomalies of +3°C to +5°C.

“The report empowers countries and governments as they continue to experience intense heat and come to grips with the impact of climate change,” Thomalla says. “I would like to extend a special thank you to those who contributed content at pressurised times. It was amazing to see everyone rallying together to get the job done, and I look forward to working on next year’s submission.”