In the summer months of 2023, the world experienced a sweltering heat wave not felt in recent memory. Across various regions of the northern hemisphere, hot spells of varying lengths and intensities concurrently wreaked havoc. This wasn’t just a routine warm spell – it was a blistering wave of heat breaking records across the globe.
The Forensic Disaster Analysis (FDA) Task Force Group of KIT’s CEDIM set out to investigate this meteorological phenomenon. The team analyzed the staggering temperatures that regions witnessed and the heightened exposure of populations to this extreme heat.
What was truly astonishing was the scale at which previous records were smashed. While some areas observed never-before-seen all-time highs, others saw new daily or even monthly records. Turning an eye to the oceans, the global mean surface temperature in June 2023 was unparalleled in recorded history.
For both land and sea, June 2023 stood out as the warmest June since records began in 1850. A worrying sign of what was to come, as the first three weeks of July 2023 turned out to be the hottest three-week period ever documented.
On July 6th, a global high of 17.08 degrees Celsius was recorded, with the temperatures of the preceding and succeeding days being only slightly cooler.
“For a big temperature anomaly to develop over a longer term, a long-lasting and unusually large-scale flow pattern is required,” explained Dr. Andreas Schäfer from the FDA Task Force Group of CEDIM.
An important factor is the pressure distribution in the middle troposphere, hovering around 5.5 kilometers altitude. This significantly influences the upper airflow and the consequential air mass transport.
“In July 2023, extraordinarily persistent high-pressure areas prevailed in the regions affected by the high temperatures. Here, descending air masses contributed significantly to warming and the local development of the heat wave.”
These alarming temperatures had a direct, palpable impact on human lives. For Germany, the findings revealed that about seven million of its residents experienced daily maximum temperatures surpassing 25 degrees Celsius. This statistic was a jarring 40 percent jump compared to averages between 1980 and 1999.
More concerningly, individuals enduring temperatures of 35 degrees Celsius and beyond doubled, landing at around 206,000. Countries like Italy, Greece, Spain, the United States, China, and India also experienced heightened heat exposure during these months.
In Europe, Italy was hit hardest. Astonishingly, temperatures soared past 40 degrees Celsius. From 1980 to 1999, only around 4,000 individuals faced such daily temperatures. In 2023, this number leaped to over 127,000.
Recognizing the severe health implications of such heat exposure, state institutions sprang into action. A series of action plans and adaptive strategies were rolled out, with measures like the installation of public wells and water dispenser systems being initiated.
As we wait for official confirmation from the World Meteorological Organization (WMO), preliminary reports suggest that many countries including the United States, Canada, and China, along with Mediterranean countries in North Africa and the Middle East, endured their hottest temperatures on record in July 2023.