September 2023 hottest on record across the world

The world's September temperatures were the warmest on record in 2023, breaking the previous high by a large amount.

The new record was based on data from the EU climate service.

It said that last month was 0.93C warmer than the average September temperature between 1991-2020, and 0.5C hotter than the previous record set in 2020.

Some scientists said they were shocked by the scale of the increase, and think that 2023 is now "on track" to be the warmest on record.

September's high temperature follows what was the hottest summer on record in the northern hemisphere, with soaring temperatures showing no signs of dropping.

The data, from the Copernicus Climate Change Service, shows that the month had the biggest jump from the long term average in records dating back to 1940.

How significant was the increase in temperature?

September temperatures in 2023 were far above any previous recorded month back to 1940 - nearly 1C higher than the period from 1991-2020.

Beating a long term recent average by almost a degree is a big deal, but experts say there were even greater differences in temperature in some parts of the globe.

2023 was a year of record-breaking temperatures

In Europe, for example, the scale of heating was remarkable, beating the long term average by 2.51C.

Scientists have been quite shocked by some of the detail in the data.

Dr Samantha Burgess, Deputy Director of the Copernicus Climate Change Service (C3S) said: "The unprecedented temperatures for the time of year observed in September - following a record summer - have broken records by an extraordinary amount."

Why was this September so much hotter?

Climate scientists believe emissions of gases like Carbon Dioxide are causing climate change, in addition to the El Niño weather event also driving the heat.

El Niño is declared when the water warms up by half a degree Celsius higher than the long term average.

During El Niño events, warm water comes to the surface in the East Pacific, releasing additional heat into the atmosphere.

One important measure that climate researchers look to is the difference between current temperatures and what they were before the widespread use of fossil fuels, like coal, oil and gas.

Last month was around 1.75C above the level temperatures were at before fossil fuels were in use.

This is also the highest figure for a single month ever recorded.

Political leaders meeting in Paris in 2015 agreed to try and hold the rise in global temperatures under 1.5C this century.

September's rise in temperature isn't a breach of that agreement, because the Paris target refers to decades not months - but it could put more pressure on politicians to act, as they prepare to gather for the COP28 climate summit at the end of November.

Will there be more record breaking temperatures for the rest of 2023?

In 2023 the eight months between January and September have seen a 0.05C temperature rise - higher than even recorded in 12 months of 2016, which until now had been the hottest year.

Extreme heat has continued into October, smashing monthly high records in many locations including in Spain.

Scientists believe that this year as a whole will stay under that 1.5C limit, but say 2023 is "on track" to become the warmest on record, according to Copernicus.

There is a chance global temperatures could continue to get even hotter as the El Niño weather event is yet to peak.