Climate: US podium: Daily temperatures break previous record

Berlin The previous daily record from University of Maine Climate Analysis data, dating back to 1979, was 16.92 degrees on August 13 and 14, 2016, and the value was reached again in July 2022.

Helge Gosling of the Alfred Wegener Institute (AWI) in Bremerhaven explained that more records are certainly possible in the next few weeks. Throughout the year, the highest values ​​are usually reached around the end of July, when large land masses in the northern hemisphere are particularly heated. “By then, the records of the past few days could still be surpassed.”

Increase background level

According to experts, exceptionally high sea surface temperatures in the North Atlantic and other marine regions have an impact on the current development. Gosling explains that this ensures that air temperatures near the surface over the ocean and continents fluctuate around an increasing background level. This, in turn, increases the likelihood of new temperatures being recorded, daily, monthly as well as yearly. “As long as we are at a high level of background, we have to expect new records.”

In general, it is not surprising that there are more and more high temperature records. “While global warming initially increased moderately from decade to decade, the rate of change increased gradually,” Gosling said. Therefore, more and more new records are expected.

Just on Thursday, the European Union’s Copernicus Climate Change Service reported that June was the warmest in the world since records began in 1979. For the first time in many years, El Niño is also prevalent in tropical regions of the Pacific Ocean, the World Weather Organization (WMO) announced. Recently. This natural weather phenomenon can also lead to higher temperatures, which are already rising steadily in the context of the climate crisis—the record year 2016, for example, was an El Niño year.

“El Niño should already have a large stake in the global average temperature records,” Gosling explained. “Because ocean temperature 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 will not be reached until the second year of an El Niño event. “However, given current developments, it is becoming increasingly likely that the latest record from 2016 will be amenable to a 2023 match – despite mild conditions at the end of a prolonged La Niña phase earlier in the year.”

in ratings climate analysis tool This is what is called reanalysis. “Reanalyses are a combination of observational data – data from satellites, weather balloons, weather stations and a range of other measurements – and weather models,” explained AWI researcher Helge Gößling.

The Climate Analysis Tool is one of several platforms that use reanalysis such as the European Center for Medium-Range Weather Forecasts (ECMWF) ERA5. Due to differences in the data feeds and models used, datasets can vary significantly both locally and in the short term – the larger the areas considered, the smaller the differences typically become. “In the case of a global average temperature anomaly, the differences are usually very small.”