
Temperature records have been broken every month for the past 12 months
June 2023 didn’t seem like an exceptional month at the time. It was the warmest June on record, but monthly records aren’t exactly unusual in a period where the 10 warmest years on record have all occurred in the past 15 years. And monthly records have often been recorded in years that are otherwise nothing special; back then, the warmest July on record was in 2019, a year that doesn’t stand out much from the rest of the past decade.
But July 2023 set another monthly record, far surpassing the high temperatures of 2019. Then another monthly record was set in August. And so has every single month since then – a string of records that made 2023 the warmest year on record.
On Wednesday, the European Union’s Earth observation service, Copernicus, announced that a full year has now passed since sufficient instruments were put in place to monitor global temperatures, and each month has been the warmest version of that month.
The monthly temperature trend shows how extreme the temperatures were last year.Courtesy of C3S/ECMWF
As you can see from this graph, most years have a mixed bag of temperatures – some higher than average, some lower. Months with exceptionally high temperatures tend to be frequent, but these clusters also tend to last less than a full year.
There was a similar one-year record series in the Copernicus data in 2015/2016. NASA, which uses slightly different data and methods, does not show a similar series for this earlier period. NASA has not yet published its results for May temperatures – they are expected in the next few days – but it is very likely that the results will also show a one-year record series.
Beyond the records, the EU points out that temperatures in the one-year period to May were 1.63 degrees Celsius above the average temperatures of the 1850-1900 period, which is used as a baseline for pre-industrial temperatures. This is notable because many countries have reportedly committed to not increasing temperatures by more than 1.5 degrees Celsius above pre-industrial conditions by the end of the century. While it is likely that temperatures will fall back below the target at some point in the next few years, the new records suggest that we have very little time left before temperatures are permanently above it.
For the first time since weather records began, temperatures were consistently more than 1.5 degrees Celsius above the pre-industrial average.Courtesy of C3S/ECMWF