WMO confirms 2024 as hottest year on record, exceeds 1.5° threshold

CHENNAI: The World Meteorological Organisation (WMO) has confirmed that 2024 is the warmest year on record. Moreover, all the top ten warmest years were during the last decade from 2015 to 2024.

As per WMO release, the global average surface temperature was 1.55 °C (with a margin of uncertainty of ± 0.13 °C) above the 1850-1900 average. This means that the world has experienced the first calendar year with a global mean temperature of more than 1.5°C above the 1850-1900 average (pre-industrial era). The Paris Agreement in 2016 set a goal to limit the global temperature rises only up to 1.5°C from the pre-industrial era.

The finding was based on analysis of datasets from the European Center for Medium Range Weather Forecasts (ECMWF), Japan Meteorological Agency, NASA, the US National Oceanic and Atmospheric Administration (NOAA), the UK’s Met Office in collaboration with the Climatic Research Unit at the University of East Anglia (HadCRUT), and Berkeley Earth.

“Today’s assessment from the World Meteorological Organisation (WMO) proves yet again – global heating is a cold, hard fact. Individual years pushing past the 1.5 degree limit do not mean the long-term goal is shot. It means we need to fight even harder to get on track. Blazing temperatures in 2024 require trail-blazing climate action in 2025. There's still time to avoid the worst of the climate catastrophe. But leaders must act – now," the release quoted UN Secretary-General Antóno Guterres.

Short-term temperature spikes in long-term warming can be caused by naturally occurring phenomena like El Niño, which persisted from mid-2023 to May 2024. As global warming continues, there is an urgent need for careful tracking, monitoring and communication with regard to where the warming is relative to the long-term temperature goal of the Paris Agreement, to help policymakers in their deliberations, the WMO said.

Meanwhile, a separate study published in Advances in Atmospheric Sciences found that ocean warming in 2024 played a key role in the record high temperatures. The ocean is the warmest it has ever been as recorded by humans, not only at the surface but also for the upper 2000 meters, according to the study led by Prof. Lijing Cheng with the Institute of Atmospheric Physics at the Chinese Academy of Sciences. It involved a team of 54 scientists from seven countries and 31 institutes.

About 90% of the excess heat from global warming is stored in the ocean, making ocean heat content a critical indicator of climate change. From 2023 to 2024, the global upper 2000 m ocean heat content increase is 16 zettajoules (1021 Joules), about 140 times the world’s total electricity generation in 2023, according to the study, which is based on the Institute of Atmospheric Physics dataset.

On the other hand, Copernicus Climate Change Service explained that the human-induced climate change remains the primary driver of extreme air and sea surface temperatures; while other factors, such as the El Niño Southern Oscillation (ENSO), also contributed to the unusual temperatures observed during the year.

In 2024, extreme weather events were observed worldwide, ranging from severe storms and floods to heatwaves, droughts and wildfires. The increasing frequency and intensity of such events pose a significant risk to the livelihoods of people across the globe. The total amount of water vapour in the atmosphere reached a record high in 2024, at about 5% above the 1991–2020 average — significantly higher than in 2023. This abundant supply of moisture amplified the potential for extreme rainfall events. In addition, combined with high sea surface temperatures, it contributed to the development of major storms, including tropical cyclones.