The latest State of the Global Climate report confirms 2024 as the hottest year since records began 175 years ago, with a global mean temperature of 1.55°C above pre-industrial levels – surpassing the critical warming threshold of 1.5°C for the first time.

While a single year above 1.5°C doesn't break the Paris Agreement's long-term goals (a long-term average below 1.5°C), it is a stark warning of the urgent need for emissions reduction.

Multiple climate indicators also set new records. Atmospheric carbon dioxide concentrations are at their highest in 800,000 years, and the oceans continue to warm at unprecedented rates.

Glaciers and sea ice are rapidly melting, contributing to a rise in global sea levels that threatens coastal ecosystems and infrastructure worldwide.

Furthermore, tropical cyclones, floods, droughts, and other hazards last year led to the highest number of new displacements recorded in 16 years, contributing to worsening food crises, and fuelling massive economic losses.

Leveraging renewables and early warning systems

Despite these alarming trends, UN Secretary-General António Guterres said that the Paris Agreement goals are still achievable and called on world leaders to step up their efforts in response to the mounting crisis.

“Our planet is issuing more distress signals – but this report shows that limiting long-term global temperature rise to 1.5 degrees Celsius 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’’, he urged.

WMO Secretary-General Celeste Saulo called the report findings a “wake-up call” to the increasing level of deadly risk facing human life, economies and the planet.

“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. We are making progress but need to go further and need to go faster”, she said.

Irreversible changes

The report explains that the record-breaking global temperatures in 2023 and 2024 were primarily driven by increasing greenhouse gas emissions, amplified by the transition from La Niña to El Niño.

Other factors that might have contributed include solar cycle variation, volcanic activity and changes in ocean circulation.

Scientists also underscore the urgency of taking action, outlining some already irreversible changes – including the rate of sea level rise – that has doubled since satellite measurements began.

Projections show that ocean warming, which reached its highest level on record, will continue over the rest of the 21st century and beyond, even if the world were to significantly reduce emissions. Similarly, ocean acidification will continue to increase for the rest of this century, at rates dependent on future emissions.

Other key findings

• Globally, each of the past ten years were individually the ten warmest years on record.
• Each of the past eight years has set a new record for ocean heat content.
• The 18 lowest Arctic sea-ice extents on record were all in the past 18 years.
• The three lowest Antarctic ice extents were in the past three years.
• The largest three-year loss of glacier mass on record occurred in the past three years.
• In 2024, ocean heat content reached its highest level in the 65-year observational record.
• Tropical cyclones were responsible for many of the highest-impact events of 2024. These included Typhoon Yagi in Viet Nam, the Philippines and southern China.