The record for the hottest average global temperature over a 24 hour period has been exceeded four times this so far in July 2023, according to the Climate Reanalyzer tool at the University of Main's Climate Change Institute. On Monday 3 July the average global temperature was 17.01°C, exceeding a previous global average of 16.89°C set on Monday 25 July 2022 by 0.11°C. On Tuesday 4 July the average global temperature reached 17.18°C, beating Monday's record by a further 0.17°C. Two days later, on Thursday 6 July, the temperature reached 17.23°C, exceeding Tuesday's temperature by a further 0.05°C, and the highest pre-July 2023 global temperature recorded by 0.34°C.
Average global temperatures between 1979 and 2023. Climate Reanalyzer.
The average temperature is warmest in the northern summer, as there is a greater land-area in the Northern Hemisphere, and the atmospheric temperature over land is more prone to short term variations. However, the long-term trend is largely driven by the Southern Hemisphere, where there is more ocean, as the ocean's both warm and cool more slowly, due to the higher thermal inertia of water (i.e. it requires more energy to heat water). The past few years have seen exceptionally high global temperatures, despite the presence of a La Niña system over the South Pacific (the cooler phase of a long term climatic oscillation). This year the South Pacific has switched into the El Niña phase of the same oscillation system, which is predicted to drive global temperatures upwards more sharply over the next few years, potentially driving the Earth's temperature over tipping points which could alter the long-term climate of the planet.
Recorded global temperatures on Saturday 8 July 2023. Climate Reanalyzer.
The El Niño is the warm phase of a long-term climatic oscillation affecting the southern Pacific, which can influence the climate around the world. The onset of El Niño conditions is marked by a sharp rise in temperature and pressure over the southern Indian Ocean, which then moves eastward over the southern Pacific. This pulls rainfall with it, leading to higher rainfall over the Pacific and lower rainfall over South Asia. This reduced rainfall during the already hot and dry summer leads to soaring temperatures in southern Asia, followed by a rise in rainfall that often causes flooding in the Americas and sometimes Africa. Worryingly climatic predictions for the next century suggest that global warming could lead to more frequent and severe El Niño conditions, extreme weather conditions a common occurrence.
Movements of air masses and changes in precipitation in an El Niño weather system. Fiona Martin/NOAA. The Climate Reanalyzer is a climate visualization tool, rather than a model, which is to say it provides data on observed temperatures but does not attempt to make predictions from these. It draws data from a number of sources, including the National Oceanic and Atmospheric Administration and the European Copernicus Climate Change Service. As such it is not regarded as an official governmental source, but is considered a reliable source of information by climate scientists.
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