WASHINGTON - World daily temperature records have been smashed this week, according to preliminary data.
The modelling tools that produced these estimates can provide an early warning of extreme heat events, even if they aren't as precise as monthly and yearly reports produced by leading agencies, say experts.
The University of Maine has established an online tool called Climate Reanalyzer, which shows the curves of average global temperature for each day since 1979.
On 3 July, this curve reached a high of 17.01 degrees Celsius. That record was surpassed on Tuesday with 17.18C, and again on Thursday with 17.23C.
Europe's Copernicus Climate Change Service, which has a similar tool, later confirmed the records of Monday, and then Tuesday, albeit with slightly different figures -- 16.88C and 17.03, respectively.
"These are estimates, unofficial records," University of Maine climate scientist Sean Birkel, who developed Climate Reanalyzer, told AFP.
"The greatest emphasis should be placed on an annual and monthly timescale," he added, with these reports subject to greater checks and verifications than is possible for daily records that rely on near real-time information.
In general, climate experts prefer to focus on long-term trends and changes, in order to eliminate variations simply related to weather.
What's more, the concept of a global average temperature is a bit abstract and not necessarily as meaningful for the general public.
"No one lives in the global average," said Hausfather.
Despite these limitations, the value of daily records is "we can start to identify extreme events," which could have climate significance, said Birkel.
Though temperature at the daily timescale is weather, not climate, adding in 40 years' worth of data provides important climate context, he says.
"These provisional records provide another piece of evidence of the global climate pattern shifts due to climate change and the evolving El Nino episode," said Omar Baddour, chief of climate monitoring at the World Meteorological Organization.
"I think this is a sign that we're heading into a very hot period. June was the warmest June on record by a pretty big margin," said Hausfather. "At this point, it looks increasingly likely that 2023 as a whole will be the warmest year since records began in the mid-1800s."