August Joint-Hottest Month on Record as Climate Change and El Niño Drive Heat

August was the joint-hottest month ever recorded, tying with July 2023, according to the European Union's climate service. The record was driven by a combination of climate change and the rising influence of El Niño, which pushed heat into the atmosphere across the Pacific. Temperatures for the month were 1.65C above pre-industrial levels, surpassing the critical 1.5C threshold that countries agreed to avoid the worst consequences of climate change. While a single month above 1.5C does not mean the limit has been permanently crossed, it demonstrates a trend towards breaching it.

The month also capped western Europe's warmest summer, with high temperatures pushing the season past the deadly heat of 2003. Dr Samantha Burgess, strategic lead for climate at Copernicus, described August as "a remarkable month in the global climate record", noting that its impacts had been "increasingly being felt by communities, economies and ecosystems across the world". The combination of record air temperatures, record ocean heat and Europe's exceptional summer showed how climate change was now driving extremes across "both the atmosphere and the oceans", she said.

Simon Stiell, the UN climate chief, said the record clearly showed humanity's impact on the climate. "The evidence is irrefutable: this is the spiralling price of humanity's fossil fuel addiction, and the global climate crisis it is fuelling," he said.

On top of the ongoing impact of fossil fuel use, the rise of a powerful El Niño is making matters worse, researchers say. El Niño is a natural climate pattern in which a band of the eastern Pacific turns unusually warm, releasing vast amounts of stored ocean heat into the atmosphere and nudging global temperatures upwards for around a year. The one currently being experienced is still strengthening and could become one of the most powerful on record, according to the Copernicus team. The biggest impact of this natural phenomenon on global temperatures is expected over the coming year, meaning the current run of records may have further to go.

That prospect follows a summer that drove western Europe to its warmest on record. This was echoed in the UK, which had its hottest summer since records began in 1884 — a high mark the Met Office found had been made around 130 times more likely by human-caused climate change. These figures carried "a very real human cost", said Dr Clair Barnes, an extreme weather researcher at Imperial College London. The heat across the UK and Europe disrupted schools, strained hospitals, hit food production, fuelled fires and drought, and claimed "tens of thousands of lives", she said.

She rejected the idea that such summers were now simply the "new normal". "Until we stop burning fossil fuels these records will continue to tumble, and the extremes will worsen faster than we are able to adapt. Crucially, how much worse we allow it to get remains within our hands."