UN warns of 'climate breakdown' after northern hemisphere's hottest summer

This year has seen the hottest northern hemisphere summer ever measured, according to the World Meteorological Organization (WMO).

"Our planet has just endured a season of simmering — the hottest summer on record. Climate breakdown has begun," UN secretary-general Antonio Guterres said on Wednesday, 6 September.

Scientists have said the burning of coal, oil and natural gas for human activity is driving ever-higher temperatures around the globe as greenhouse gases accumulate in the atmosphere and hold in heat. This year, El Niño, a temporary warming of parts of the Pacific Ocean that occurs naturally, has also played a role in raising global temperatures.

Last month was the hottest August ever recorded with modern equipment, according to WMO and the European climate service Copernicus. However, it was also the second-hottest month measured, exceeded only by July 2023, and the third month in a row to set a monthly heat record, Copernicus said.

August was about 1.5°C (2.7°F) warmer than pre-industrial averages, scientists said. That temperature rise is the threshold that the 2015 Paris climate accord agreed to target as a maximum aspirational average for the world. However, reaching 1.5°C for a brief period does not yet mean a failure to stick to that target.

The average sea surface temperatures also hit a record level in August, at 20.9°C.

So far, 2023 has been the second-hottest year on record, behind 2016, according to Copernicus, but could well end up being the hottest, with September seeing above-average temperatures in many regions thus far.

The rising global temperatures have brought heat waves, droughts, wildfires and flooding to several parts of Asia, Africa, Europe and North America over the last three months.

Guterres put the blame for climate change squarely on humans. "Scientists have long warned what our fossil fuel addiction will unleash," he said. "Our climate is imploding faster than we can cope, with extreme weather events hitting every corner of the planet. Surging temperatures demand a surge in action. Leaders must turn up the heat now for climate solutions."

A report by UN experts is due this week to evaluate the world's progress in meeting the 1.5°C goal. The report comes ahead of a UN climate summit in Dubai starting on 30 November.