UN warns of 'climate breakdown' as 2023 recorded the hottest in history

UN chief Antonio Guterres warned that the climate was breaking down after the EU monitoring body said 2023 was likely to be the hottest year in human history.

"Our planet has just endured a season of simmering - the hottest summer on record. Climate breakdown has begun," Guterres said on Wednesday.

"Surging temperatures demand a surge in action. Leaders must turn up the heat now for climate solutions," he added.

Summer 2023: Unprecedented heatwaves

Heatwaves, droughts and wildfires struck Asia, Africa, Europe and North America over the last three months, with dramatic impact on economies, ecosystems and human health.

The average global temperature in June, July and August was 16.77 degrees Celsius (62.19 degrees Fahrenheit), smashing the previous 2019 record of 16.48C, the European Union's Copernicus Climate Change Service (C3S) said in a report.

"The three months that we've just had are the warmest in approximately 120,000 years, so effectively human history," C3S deputy director Samantha Burgess said.

Warming oceans: Absorbing heat

Oceans have absorbed 90 percent of the excess heat produced by human activity since the dawn of the industrial age, according to scientists.

This excess heat continues to accumulate as greenhouse gases - mainly from burning oil, gas and coal - build up in the Earth's atmosphere.

Record-high global sea surface temperatures played a major role in stoking heat throughout the summer, with marine heatwaves hitting the North Atlantic and the Mediterranean Sea.

The average ocean temperature has been topping seasonal heat records on a regular basis since April.

Warmer oceans are also less capable of absorbing carbon dioxide (CO2), exacerbating the vicious cycle of global warming as well as disrupting fragile ecosystems.

Antarctic sea ice remained at a record low for the time of year with a monthly value 12 percent below average, "by far the largest negative anomaly for August since satellite observations began" in the 1970s, C3S said.

"Looking at the additional heat we have in the surface ocean, the probability is that 2023 will end up being the warmest year on record," Burgess said.

Scientists expect the worst effects of the current El Nino to be felt at the end of 2023 and into next year.