In a new report, the UN agency confirms that 2024 was likely the first calendar year to be more than 1.5°C above the pre-industrial era, with a global mean near-surface temperature of around 1.55°C above the 1850-1900 average.
This is the warmest in the 175-year observational record, mainly due to the ongoing rise in greenhouse gas emissions, coupled with a shift from a cooling La Niña to warming El Niño event, with atmospheric concentrations of carbon dioxide at “the highest levels in the last 800,000 years”.
The report also reveals that last year’s global mean sea level was the highest since the start of the satellite record in 1993, and that the rate of increase from 2015-2024 was double that from 1993–2002, increasing from 2.1 mm per year to 4.7 mm per year.
“Our planet is issuing more distress signals,” said UN secretary-general António Guterres. “But this report shows that limiting long-term global temperature rise to 1.5°C is still possible.
“Leaders must step up to make it happen, seizing the benefits of cheap, clean renewables for their people and economies, with new national climate plans due this year.”
Around 90% of the energy trapped by greenhouse gases in the Earth system is stored in the ocean, with 2024 seeing ocean heat content reach its highest level in the 65-year observational record.
Indeed, each of the past eight years has set a new record, with the rate of ocean warming over the past two decades from 2005-2024 more than twice that in the period from 1960-2005, and is set to continue for at least the rest of the 21st century, even for low-carbon emission scenarios.
The report also explains how the period from 2022-2024 represented the most negative three-year glacier mass balance on record, and how seven of the 10 most negative mass balance years since 1950 have occurred since 2016.
Furthermore, extreme weather events in 2024 led to the highest number of new annual displacements since 2008, destroying homes, critical infrastructure, forests, farmland and biodiversity.
“In response, WMO and the global community are intensifying efforts to strengthen early warning systems and climate services to help decision-makers and society at large be more resilient to extreme weather and climate,” said secretary-general Celeste Saulo.
“We are making progress but need to go further and need to go faster. Only half of all countries worldwide have adequate early warning systems. This must change.”
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Chris Seekings is the Deputy Editor of IEMA’s Transform magazine, which is published biomonthly for IEMA members. Chris’s role involves writing sustainability-related news, features and interviews, as well as helping to plan and manage the magazine’s other day-to-day activities.