A World Meteorological Organization (WMO) report confirmed that 2023 was the warmest year on record, with global average surface temperatures at 1.45 degrees Celsius (2.61 Fahrenheit) above pre-industrial levels.
The UN agency warned that the changes were interwoven with growing food insecurity and population displacement.
What the report showed
The WMO study showed broken records across numerous parameters, including greenhouse gas levels and temperature.
The agency noted particularly alarming changes at sea, with a worrying rise in surface levels and acidification.
Its report said Antarctic sea ice loss, rising ocean heat, and glacier loss were of particular concern.
Antarctic sea ice extent was "by far the lowest on record," with the maximum extent at the end of winter at 1 million kilometers squared below the previous record year — the size of France and Germany combined.
Glaciers suffered the largest loss of ice on record, driven by "extreme melt" in both western North America and Europe.
The authors also pointed out increasingly frequent heatwaves, floods, droughts, wildfires, and intensifying tropical cyclones.
They caused "misery and mayhem, upending everyday life for millions and inflicting many billions of dollars in economic losses."
What is the UN agency's warning?
The organization's Secretary-General Celeste Saulo said the world had never been so close to, at least temporarily, exceeding the 1.5 degrees Celsius (2.7 degrees Fahrenheit) lower limit of the Paris Agreement on climate change.
"The WMO community is sounding the red alert to the world," said Saulo.
A report by the European Union's Copernicus Climate Change Service (C3S) last showed average global surface temperatures for 2023 had actually nudged above the threshold.
"Climate change is about much more than temperatures," said Saulo. "What we witnessed in 2023, especially with the unprecedented ocean warmth, glacier retreat, and Antarctic sea ice loss, is cause for particular concern."
The report drew attention to the number of people who are acutely food insecure worldwide, noting this had grown from 149 million people before the COVID-19 pandemic to 333 million in 2023.
"The climate crisis is the defining challenge that humanity faces and is closely intertwined with the inequality crisis — as witnessed by growing food insecurity, and population displacement, and biodiversity loss," Saulo said.
Professor Tina van de Flierdt of Imperial College London said the latest WMO report "reinforces that climate change is not a distant threat — it is here now."
WMO climate monitoring director Omar Baddour said: "There is a high probability that 2024 will again break the record of 2023."
Finally, some good news
While its warning was dire, the WMO highlighted "a glimmer of hope" in the form of the increased use of renewable energy.
Renewable energy capacity saw its greatest rate of increase over the past two decades in 2023, growing by 510 gigawatts (GW), 50% more than was added the previous year.
"Renewable energy generation, primarily driven by the dynamic forces of solar radiation, wind and the water cycle, has surged to the forefront of climate change action for its potential to achieve decarbonization targets," the report said.
"We're seeing year on year increases in the amount of energy being produced in that way, so that's that's one kind of positive thing that's happening," WMO scientist John Kennedy told DW.
"We're moving in the right direction in terms of energy generation."
