climate
US platform: Daily temperatures break previous record
A weather balloon with a radiosonde rises into the sky. photo
© Patrick Pleul/dpa-Zentralbild/dpa
The previous global heat record from 2016 was already surpassed at the beginning of the week. According to an analysis, the days after that also brought extreme values. The record phase of the year has not yet been reached.
The previous daily record from the University of Maine’s “Climate Reanalyzer” data, which dates back to 1979, was 16.92 degrees on August 13 and 14, 2016, and the value was reached again in July 2022.
Further records are definitely possible in the next few weeks, explained Helge Gößling from the Alfred Wegener Institute (AWI) in Bremerhaven. In the course of the year, the highest values are typically reached around the end of July, since that is when the large land masses in the northern hemisphere are particularly heated. “By then, the records of the past few days could still be surpassed.”
Increased background level
According to experts, persistently exceptionally high temperatures on the sea surface of the North Atlantic and other sea regions are having an impact on the current development. This ensures that the near-surface air temperatures over the ocean and continents fluctuate around an increased background level, explained Gößling. This in turn increases the likelihood of new temperature records, both daily and monthly as well as annually. “As long as we are at such a high background level, we have to expect new records.”
In general, it is not surprising if there are more and more high temperature records. “While global warming initially increased moderately from decade to decade, the rate of change has gradually increased,” said Goessling. New records are therefore to be expected more and more frequently.
Only on Thursday did the EU climate change service Copernicus report that June was the warmest in the world since records began in 1979. For the first time in several years, El Niño conditions are also prevailing in the tropical Pacific, as the World Weather Organization (WMO) recently announced. The natural weather phenomenon can also drive up the temperatures, which are already constantly rising in the course of the climate crisis – the record year 2016, for example, was an El Niño year.
“El Niño should already have a significant share in the globally averaged temperature records,” explained Goessling. “As ocean heat has a longer memory and El Niño is likely to continue to develop, we can expect the second half of the year to remain warm globally.”
Observational data and weather models
Typically, new global warming records for annual surface temperatures would not be reached until the second year of an El Niño event. “However, given current developments, it is becoming increasingly likely that the last record set in 2016 could be matched as early as 2023 – despite the moderate conditions at the end of a prolonged La Niña phase earlier in the year.”
The evaluations of “Climate Reanalyzer” are so-called reanalyses. “Reanalyses are a combination of observation data – satellite data, weather balloons, weather stations and a range of other measurements – and weather models,” explained AWI researcher Helge Gößling.
The “Climate Reanalyzer” is one of several platforms using reanalysis, such as “ERA5” from the European Center for Medium-Range Weather Forecasts (ECMWF). Due to differences in the data feed and the models used, the data sets could differ noticeably locally and in the short term – the larger the areas considered, the smaller the differences typically become. “With the globally averaged temperature anomaly, differences are usually very small.”